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IPMEOLOGICAL STRENGTH AND DURABILITY
CHARACTERISTICS OF
SISAL FIBRE WINFORCED CEMENTITIOUS COMPOSITES
TMESIS
DOCTOR OF PHILOSOPHY
in
CIVIL ENGINEERING
BY
GUDIAMELLA RAMAKRISMNA
DEPARTMENT OF CIVIL ENGINEERING
PONDICHERRY ENGINEERING COLLEGE
PONDICHERRY - 605 014
APRIL 2005

i hcrcb! dcclarc rhar this 7'hcsis ~:ititlcc1 RHEOLOCICAL STRENGTH AND
DUPIABIESTY CHAMCTERISTECS OF SISAL FIBRE REINFORCED
CEMEKT'dTIBUS COMPOSITES submitted to ihtl Pondicherry University for the
n1ial.d of the degrec of' DOCTOR OF PHILOSOPHY in Civil Engilteeri~g is a
.. ,ciord ,. nrigin2.i ~vork done by :ne under :he cc;len.ision of Dr.T.Sundararajan. and
that it has not formed the b~sis for the atyard ~ \f iill!.
or any other title by any L;~iversity ,' Institution before.
other Degree ! Diploma i Certificate
Place: Pondicherry
Date: 25 - 04 - 2005

This is to certifl !!a!
Alr.GLDIA31[EkLA RAI"rlr"lKRESHN.4 has single - handedly
carried oilt the hark embodied ic tixs Thesis entitled : NEOLOGICAL
STRENGTH AND DUMBILITY CHARACTERISTICS OF SISAL FIBRE
REBYFORCED CEI1I7ENTfT%OUS COMPOSITES being sub13itted for the award
of the Degree of Doctor of Plnr'losqB~y of Pondicherv University He has complied
with all ihe relekant academic and administrati\e regulations and d~athe Thesis embodies
a bonafide record of an independect work done hy h!~: under m> supervision. This work is
original and has not been submitted for the award of any other Degree/ Diploma /
Certificate of this or any other University.
Place: Pondicherry-14
~ate:Ac,- 04 - 2005
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The a-iit!~or svishes to espress his deep sense of gratitude to Dr.T.Sundararajan, Professor
of Civil Engineering, Pondicherrl; Engireering Coilege, Pondicherry-14, for his
motivation. invaluable suggestions and personal supervision of the work. The author
sincerely appreciates his deep u~;de:standing. kea interest, untiring en~husiasm, and
constant care he took in shapins this Thesis. 'fhe author also acknowledges his meticulous
esa!uation of tile
at sncl s!age and inimitable patience shown during the preparation
of the manuscript, apart from, the cordial and affeciionate treatment.
Suggestions and encouragement given by Dr.D.Govindarajulu, Professor and
Dr.S.Sivarnurthy Reddy. Assistant Professor, Depacment of Civil Engineering,
Pondicherry Engineering College. Pondicherry, during the various stages of the Thesis, is
thankfully aclu~owledged.
Dr. S.Kothandaraman: Professor, and Dr.V.L.Narasimha, Assistant Professor, Department
Civil Engineering, Pondicherry Engineering College, Pondicherry, have extended their
timely support for utilizing the laboratory facilities and by providing valuable literature,
which are acknowledged with gratitude.
Constant encouragement and suggestions given by all other Faculty members of the
Dept.of Civil Engineering, is greatly appreciated. The author wishes to express his
gratitude to the Principal, Pondicherry Engineering College, (PEC), Pondicherry, for
having permitted to utilize the Library and other facilities available in the Institute.
The author appreciates the assistance rendered by the Laboratory Staff (Technical / Non-
Technical) of the Department of Civil Engineering, PEC, Pondicherry, in fabrication and
conducting the various experiments relating to this Thesis. The kind cooperation and help
extended by some of the Faculty of Chemistry and Physics, PEC, Pondicherry, for
carrying out some of the tests reported in this work, is gratefully acknowledged.
The author wishes to express his whole - hearted thanks to the Librarian, PEC, and his
Staff members, for their help and support in collecting the literature relevant to the present

st:id\. Siilcer:: thanks to the authorities of NLC. Se>.s.eii, hr the snppiy of fl~fash used in
the preseci inicsligation. Scientists of tile Concrete Composite Lab, and Library Staff,
SERC. Chennai, are also thanked for tl-ieir kid suggestions, and t'or estending the Library
the facilities extended to collect vzluabie iiterarure.
The author express his indcbtness and sincere thanks to Dr. S.Krishnamoorthy, Professor
of CII il Engineering Ccparrrcer~t. iiietd.). I!T. 3t.n Delhi. for his motivation and valuable
saggt.s!ions at !!lr early stages of initiation of ccse2rci1 ;.iork in this area, which finally
helped in the completion ofa portiali of\vork reported in this Thesis
The author acknowledges bvith a sense of deep gratitude the kind support extended by the
following individuals, who have graciously spared \.ahable literature relevant to the
present work. Dr.R.N.Swamy, Professor, University of Sheffield, Sheffield, U.K;
Dr.K.Ghavami, Professor, Dept. Of Civil Engg.. PUC, Rio de Janeiro, Brazil; Dr.
1Romildo.D. Toledo Filho, Professor, Federal University of Rio de Janeiro, Rio de
Janeiro, Brazil; Dr. Nolmer Savastanov Jr.,Professor, University of Sao Paulo, Brazil;
Prof.(Dr.)Kurharska, Wroclaw Technical University, Poland; (Ms) Dr.C.F.Ferraris,
Building & Fire Research Lab., Natl. Inst. Of Standards & Technology (XIST), Madison,
USA; Dr.Charles. K. Kankam, Professor of Civil Engg., Kwame Nkrumah University of
Science and Technology, Kumasi, Ghana; Dr.(Ms.)Zal;iah .Ahmad, Associate Professor,
Faculty of Civil Engineeing, Universiti Teknologi Mara (UiTM), Malaysia;
Dr.B.Ventkatrama Reddy, Department of Civil Engineering, lISc.,Bangalore, India, and
Dr.R.Siddique, Professor of Civil Engg.Dept., Thapur Institute of Technolgy (Deemed
Univerisity), Patiala, India.
The author also thanks Dr. N. Parthasarathi, Reader, Department of Ecology and
Environmental Sciences, Pondicherry University, Pondicherry, for providing some basic
literature on natural fibres.
The author is grateful to DST,Govt.of India and AICTE, Govt.of India, for providing
research funds under R&D scheme, which has helped to fabricate the experimental set-ups
and also to carryout substantial part of the experimental investigation, reported in this
Thesis. Without their financial assistance this project work could not have been carriedout
comprehensively and completed satisfactorily.

X:e authcr also rhall;s ~l~t: filmily of Dr.T.S;iidarar-cn for their kine undcrsiandii~g and
pztiznce sho~sn, Curing the preparation of this Thcsis.
The wthor also records his deep secse r.f grati~udt: rc his \i lfe hlrs.Sreevani, C.. and their
children iif(isier Bhanumitra ar:d &rb~ Srcelcliha. for their understanding and patience
silonn, during thc pied 3f !he research progracllne
Finaliy,the author ~vishes 10 record his sincere gratitude to his beloved Parents, for their
strong \dl. sacrisce and siippor; n-hich !lave co!tributled in shapin~ -up his life and
helped to atlair the posi~ion \\,hat he 14s to-day. To then1 this Thesis is reverently
dedicated.
GUDIAMELLA RAMAKRISHNA

Cement conposites using 1,sriou.: tyges of fibres is a reiati\,ely new construction niaterial
de~.cloped through estensii.~ research during the iast three decades. Even though interest
on his new material generated abour three decades ago, iarge - scale use of the cement
composites has been on the increase only over the past fifteen years. Several organizations
in India and abroad have been carrying out research and development work on fibre
reinforced cement cor~posites - (FRC) since the early 1970's, especially, on synthetic
fibres. Hoi3sever: investigations on the scitabili~ of natural fibres (i.e. plant 1 vegetable
origic) as reinforczment in ceixent matrices h: producing huiiding materials for low - cost
housing. have been initiated on! during :!~c las: tv~o decades.
Studies or! wet - state propeiles of czn~e:~s~cenc;titio~:s matcririls are also inlportant apart
from hardened slate properties. for better understanding of the behaviour and assessing
their suitability as a building material. Traditionally, the \vei state properties have been
studied using various workability tests. which are mostly empirical, and do not measure
the inherent property of the material. Moreover, such tests created difficulties in
comparing the results from different ~ilethods and the experimental results of various
investigators, and to stipulate specifications for mix proportioning. To overcome the above
problem, a pioneering research worii on 'rheology of cement Icementitious materials' in
U.K was initiated and is in progress for the past 2 to 3 decades, in various developed
countries. As a result of such efforts, Rheometers 1 Viscometers for determining the basic
rheological parameters, namely, 'yield stress', and 'plastic viscosity' have been developed,
evaluated, and calibrated for a variety of cement 1 cementitious materials. But the above
instruments are very costly and not that easily available in developing countries. However,
certain conventional and non - conventional methods have the scope and potential for
evaluating the rheological characteristics of composites, which needs to be advantageously
exploited. Based on the comprehensive review of published literature, it is found that there
is still scope for further and wider study on the cement / cementitious system with natural
fibres, to arrive at a proper mix proportion having good workability, and without
compromising much on the strength and durability of the composite.
One of the inherent drawbacks of natural fibres i.e, embrittlement in an alkaline medium
can be improved by various methods. Among them, use of 'mineral admixtures' in the
composite is found to be the effective method, with several advantages. Of the several
pozzolans that are used in cement system even though, flyash is abundantly and widely
available, the actual utilization is very less. However, there is scope for its larger
utilization in cement systems. Moreover, its reported use in natural fibre composites, is
rather rare and scarce. Hence, there is a necessity for a comprehensive study on such
composites, i.e. natural fibre flyash cement composites.
Therefore, in the present study, a preliminary investigation was conducted in terms of four
natural fibres namely, coir, sisal, hibiscus cannebinus and jute and based on that, sisal
fibres were chosen for workability and rheological studies on the mortar composites. Flow
table test (to determine the 'mobility' of the mix) and the 'direct box shear test' commonly
used in Geotechnical Engineering (to determine the 'stability' of the mix) for three mix
proportions (13, 1:4 and 1.5) at various aspect ratios (upto 300), flyash contents (10 -
70%) and fibre contents (0.25 - 2.0%), were considered.

Stxfigrh (c~nipressi\~e. flexural, split - tensiic) c2-1arcter1stics of the composites, flexural
and impact strength ciarac;esis!ics of xortar composirc 51313s and durability of composites,
.isere experin;entnil> delernxined for !:3. at a consiar~t flow vaiue (I 10%) for the above
range oi'fg~ash and iibr.; contents. Sisal f bre reoiing shee:s were cast rr,anualI>~ (12, flow
\ LILIL 13.> = 65%: flyash = I9 - 3096; fbre content = 0.2596 - 2.0%). Performance of the above
composite sheets (flexural and sp!itting loads, impacr strength. water absorption and water
tightness characteristics), \yere esperirnental!~ evaluated and compared with that of a
popuiar comnercial rocfing sheet, available in !r.din.
.Ii*rom
the compreiiensi~e esperin~entai resulis, :he \yarer - demand in terms of WIB ratios
for a deslicd f!on \ai~:c and cohesion and the inilucnces of ilyosh and sisal fibre contents
on \V/B ratios of iile cernenli~ious composites, haw bcen I~ighiighted. The rmge of fibre
contents and aspect ratios, which are desirable to echieve cenair, levels of workability, and
the rheological characteristic (i.e. cohesion), have been ider-itified. Moreover, the positive
influences in enhancing the various strength and durability characteristics of the
composites have also been highlighted. I! is seen that the sisa! fibre corrugated roofing
sheets is comparable to the commercial roofing sheet, available i~; India. Finally, it can be
slated that the chosen test methods can be used to evaluate the impact, flexural,
rheological and durability characteristics of the composites, with confidence. The need to
specify and carryout rheological studies and to develop specific instrumeilts to measure
rheological characteristics of natural fibre cernentitious systems, has been emphasized, in
the form of a recommendation.
(vii)

CONTENTS
DECLARATION
CERTIFICATE
ACKNOWLEDGEMENT
ABSTRACT
LIST OF CONTENTS
LIST OF TABLES
LIST OF FIGURES
Page
No.
(9
(ii)
(iii)
(vi)
(viii)
(xi)
(xvi)
CHAPTER 1 INTRODUCTION
1.1 GENERAL
1.2 NEED FOR THE PRESENT STUDY
1.3 OBJECTIVES OF THE PRESENT STUDY
1.4 ORGANIZATION OF THE THESIS
CHAPTER 2 REVIEW OF LITERATURE
2.1 GENERAL
2.2 SISAL FIBRE CHARACTERISTICS
2.2.1 CLASSIFICATION
2.2.2 PRODUCTION AND USES
2.2.3 SIZE, STRUCTURE, CHEMICAL COMPOSITION +4ND
PROPERTIES
2.2.4 DECOMPOSITION OF SISAL FIBRE IN ALKALINE
ENVIRONMENT
2.3 STUDIES ON WORKABILITY OF CEMENT / 23
CEMENTITIOUS SYSTEMS AND COMPOSITES
2.3.1 WORKABILITY - DEFINATION
2.3.2 REVIEW OF EARLIER WORKS
2.3.1 STUDIES ON CEMENT MORTAR COMPOSITES
2.4 RHEOLOGICAL STUDIES OK CEMENT I CEMENTITIOUS 23
SYSTEMS
2.4.1 RHEOLOGY - DEFINATION
2.4.2 STUDY OF RHEOLOGY - BACKGROUND INFORMATION
2.4.3 RHEOLOGY Vs WORKABILITY
2.4.4 REVIEW OF RHEOLOGICAL STUDIES
2.5 STUDIES ON NATURAL FIBRE COMPOSITES 63
2.5.1 SETTING CHARACTERISTICS
2.5.2 RHEOLOGICAL 1 WORKABILITY CHARACTERISTICS
2.5.3 STRENGTH CHARACTERISTICS
2.5.4 DURABILITY OF FIBRES AND COMPOSITES
2.5.5 PRODUCTS BASED ON NATURAL FIBRES
2.5.6 MISCELLANEOUS STUDIES / REVIEW WORKS

2.6 STUDIES OX TOGTGNNESS OF COMPOSITES 107
2.6.1 TOWGHKESS - DEFINATION
2.6.2 IhfPORTAI\;CE OF TOUGHNESS MEASUREMENT
3.6.3 MEASUREMENT OF TOUGHNESS
2.6.3 IMPORTANCE OF FLEXURAL TOUGmESS FOR KATURAL
FIBRE COMPOSITES
2.6.5 OVERVIEW OF STUDIES
2.7 CONCLUDING REMAWS 118
CHAPTER 3
EXPERIMENTAL INVESTIGATIONS
3.1 GENEML 119
3.2 MATERIAL CHARACTERIZATION: BINDERS, 119
AGGREGATES $t WATER
3.2.1 CEMENT
3.2.2 FLYASH
3.2.3 FINE AGGREGATE
3.2.4 WATER
3.3 SELECTION & PRELIMINARY INVESTIGATIONS ON 127
NATURAL FIBRES
3.3.1 SELECTION OF NATURAL FIBRES
3.3.2 PHYSICAL PROPERTIES OF NATURAL FIBRES
3.3.3 CHEMICAL COMPOSITION OF NATURAL FIBRES
3.3.4 DURABILITY OF NATURAL FIBRES - RELATIVE
PERFORMANCE
3.4 EXPERIMENTAL IWESTIGATIONS ON SISAL FIBRE 142
CEMENTITHOUS COMPOSITES
3.4.1 DIMENSIOYAL STABILITY
3.1.2 WORKABILITY CHARACTERISTICS
3.4.3 RHEOLOGICAL CHARACTERISTICS
3.4.4 STRENGTH CHARACTERISTICS
3.4.5 STRENGTH CHARACTERISTICS OF MORTAR SLAB
3.4.6 DURABILITY OF SISAL FIBRE CEMENTITIOUS
COMPOSITES
3.5 SISAL FIBRE REINFORCED CORRUGATED SHEETS 151
3.5.1 EXPERIMENTAL PROCEDURE
3.6 SUMMARY 155
CHAPTER 4
RESULTS AND DISCUSSION
4.1 GENERAL
4.2 RESULTS AND DISCUSSION
4.2.1 PROPERTIES OF SISAL FIBRES
4.2.2 DIMENSIONAL STABILITY

4.7 3 WORK.4BILITY OF SISAL FIBRE COMPOSITES
4.2.3 RHEOLOGY OF SISAL FIBRE COMPOSITES
4.2.5 COMPRESSIVE STRENGTH OF MORTAR COhilPOSITES
3.2.6 FLEXCRAL STRENGTH OF MORTAR COMPOSITES
4.2.7 SPLIT- TENSILE STRENGTH OF MORTAR COMPOSITES
4.2.8 IMPACT STRENGTH OF SLABS: MORTAR AND COMPOSITE
4.2.9 FLEXURAL STREKGTH OF SLABS: MORTAR AND
COMPOSITE (BY' FOUR-POh'T LOADING METHOD)
4.2.10 DURABILITY OF SISAL FIB RE MORTAR: COMPOSITE
SLABS
4.2.1 1 SISAL FIBRE CORRUGATED ROOFING SWEETS
4.3 SUMMARY 233
CHAPTER 5
CONCLUSIONS
5.1 GENERAL 309
5.2 CONCLUSIONS
5.3 RECOMMENDATIONS
5.4 SUMMARY 316
REFERENCES
APPENDIX - A
APPENDIX - B
APPENDIX - C

Table
No.
1.1
1.3
Over\iecv of Studies on Natural Fibre Compos~tes
Page
No.
6-9
!)ver\,ie~v of Materials Used in Cementitious Systenls of Natural Fibre
Composites
Ovcrvie\v of' I'roducts Components Ilevzlopcd and Investigated I3ased
on Nati~ral Fibre Composites
Types of Mortar and Concrete Considered for Workability Studies
Ovcrviccv oi' Rheological Mctliods ,' I:quipnicnt Ijsed ibr Ccinent
Systems and Composites
'Types of Mortar and Concrete Considered for Rheological Studies
('licinicai C'olnposition ol' Sisiil I.'ibr.cs
Physical and Mechanical Properties of Sisal Fibres
Water Absorption of Sisal Fibres
Ovcrvicw or Workability Sti~dies on C:cnicnt 1 Cemcntitious Systcnis
Overview of Rheological Studies on Cernent I'astc
O\~CI.L.~CLV oI'Illicologic~~l Stuiiics on C'cmcnt Slurries
Overview of Iilicological Studies on Cement 1 Cement -- Based Grouta
Overview of Rheological Studies on Cement Mortar
Ovcrvicw of' Rheologicnl Siudics on Concrctc
Over view of Evaluatio~l of Flexural Toughness of C,ernent i
('cr~~cnlitio~is Sysici~is
l'llysic;~l I'i~opci.~ics ol'('c~~~crl[
Properties of Raw Lignite
I'hysicai I'ropertics of Flyash
C:hc.rnical Characteristics of Flyash
1':1r1icIc Si~,c I)islrilxitio~~ o~'l~lv~~.sl~

Table
No.
Page
KO.
3.6 Comparison of Particle Size Distributions of Other Indian Flyashes uith
the Flyash Used
I:iliencss anti I ,imc Rcac~ivity 01' I:lyash
Physical Properties of Fine Aggregate
Results oi'S~e\~
analysis of Fine Aggregate
Physical Properties of Various Natilral Fibres
Overview ol'L)ural~rlily ol'Na~ural l'rbrcs Invcst~ga~cd
Overview of Durability of Yatural Fibre Composites Investigated
Overview of Impact Resistance Measurenient for Fibre Reinforced
Composites
Chemical Corilposi(ion of Various Natural Fibres After I-

Table
No.
M~xcs C'c~~!~iilc~cii li)l ( I
Fibre Reinforced $lortar
J)Wc)i.I\abili~y :~iicl iillcolog~cal Slucly oI'S1si11
Mixes Considered for (1.5) Workability and Rheological Study of Sisal
Fibre Reinforced Mortar
V'iB Ratio of Mixes Considered for (1 :3; flow value = 1 12.5%) Strength
Srlrdics of Sisal i:ihsc Rcinfhrccd Mortar
Page
No.
173
Testing Standards Adopted for Vanoils Strength Stud~cs
Quantity ol'h4a~crials iiscd (sii.c:320 x 500 x 6m1n; 1 :3) for Casting
Corrugated Sheets
4.2 (a)
4.2 (b)
4.2 (c)
4.3
Uimcnslonai Stab~li~y ol'Sisil1 1:ibrcs (Sui~.jcckti lo Lbctt~n~ alicl I)r.y~ng
Cycles)
Worltability and Rheological I'ropcrtics of Sisal 1:ibrc Ccn~cnt hiIortar
Colnposites (1:3, ~v/c = 0.645, r = 0 - 300)
Workability and Rheological Properties of Sisal Fibre Cement Mortar
Con2positcs (I:4,rrj/c = 0.645, r. = O - .7OO)
Workability uid lilicological I'ropcrtics of Sisal 1,'ibrc C'c~licnt 12lot.tas
Composites (I:& w/c = 0.645, r = 0-300)
Flow Characteristics of Flyash - Cement Mortar
(1:J;fiaslz content = 0 - 70%; VJ= 0%; r = 200)
Flow Characteristics of Sisal Fibre Cement Mortar composites
(I:S;,fl~!(~.tlr contcrrt = 0%; 1', = 0.25% - 2%; r = 200)
I;lo~v Characteristics of' 1:lyash-Ccmcnt Sisal I:ibrc Mortar Coniposilcs
(1:S;Jlyash content = 10 - 70%; V/= 0.25 - 2.0%; r = 200)
Flow Characteristics of Flyash - Cement Mortar
(1:I;Jlyash content = 0 - 70%; Vf= 0%; r = 200)
Flow Clia~.acteristics of Sisal Fibrc Ccmcnt Mortar Composites
(I:l;,/ll:oslr co~rtct~l = 0%; Vj = 0.25% - 2%; r. =200)
Flow Characteristics of Sisal Fibre Flyash-Cement Mortar Composites
(1:4;flyash content = 10 - 70%; Vf= 0.25 - 2.0%; r = 200)
Flow Cliaracteristics of Flyash-Cement Mortar
(1:5;flyash content = 0 - 70%; Vf= 0%; r = 200)
(xiii)

']'it
hlc
No.
4.10 [:low ('li;lrircici.~sl~cs ol'Sis;~l 1:iI~sc ('clnc~il Mortar ('onipositcs
(1:5; Jl),rr.tl~ c.o~rferrt = 02,; I*) = O.ZS% - 2%; r = 200)
Page
No.
242
Flow Characteristics of Sisal Fibre Flyash-Cement Mortar Colilposites
(I:S;fly(~.slt coitterir' = 10 - 70%; VJ= 0.25 - 2.0%; r = 200)
I

Titble
No.
4.26 Impact Strength of Sisal Fibre Flyash - Cenlent Mortar Conlposite Slabs
Atier Esposurc ill NaOl-l
(1:3; co11.slrrtrtj7o~r~ ~~~llre =I I2%;r = 200)
(:omparison of Residual Impact Strength Ratio of Sisal Fibre Jlyasli-
Cement Mortar Composite Slabs (Before and After Exposure in NaOH)
(1:3; ronst~nIJlow valsrr =112%;r = 2110)
Effect of'f:xposure in NaOl-1 on the I,, of Sisal Fibre 1:lyash-Cement
Mortar Composite Slabs
(I:.;
C~OII~~~JII!~/TOI~~
IYI/IICP =I i2%;r = 200)
I~lzxural 'l'oughness Indcx o!'Sisal Fibre 1;iyasIl-Ccmcnt Mortar
Composite Slabs
(1:3; constantflow value =112%; r = 200; at 120 days)
Flexural Toughness Index of Sisal Fibre Flyash-Cement Mortar Slab
Ai'tcl. I.iposr~~.c in N;101 I
(I:.;
~~oIJ.~~~~II/,/~o~~J
II(I/II~ =I l,%,;r = 200)
Comparison of Flexural Toughness Indcx oSSisa1 Fibre I'lyash-Cement
Mortar Composite Slabs (Before and After Exposure in NaOH)
(1:3; constantflow value =112%; r = 200)
Effect of NaOH on the Flexural Toughness Index of Sisal Fibre
Cornpositc Slabs
1:lcsural wid Splil~i~lg I.oads ol'Sisn1 1:ibr.c I~iyash C'cmcnt
Corrugated Roofing Sheets
(1:3; specimen size: 250 x 500 x 6mm)
1'11crgy /\bsorbcd by Sisal Fibrc 1:lyash-Ccmcnt Corrugatcd Shcets
(1 :3; with and withoutfibres)
Watcr Absorption Cha~.aclci-is~ics of 1:Iynsh-Ccmcnl Sisal Fibrc
Corrugated Shccts
(1:3; with and withoutfibres)
Water Tightness of Flyash-Cement Sisal Fibre Corrugated Sheets
(1:3; with and wit/lout,fibres; ufer 24llrs)
Page
No.
258

LIST OF FIGURES
Fig.
No.
Title
Stages in Processing of Natural Fibres from Plant to Ready to-use
Fibre Forni
Water Absorption Vs 'Time of Various Natural Fibres
I\ VIL.\~ oI'111c. I \~CIIIIICIII;I~ Sc.t-\~p fi!~ I ih~r I CII\IOII ILYI
L>cLn~ls oi'S~s,il I 1b1.c SPCCII~ICI~
Schematic View of Fibre Tension Testing Machine
Typical Stress-Strain Plot of Four Natural Fibres
Fibres Before and After Immersion in the Various Mediums
Test Set -up for Studying the Workability of Composites
Test Set - up used for Studying the Rheology of Composite
Prism Specimens for Determining the Various Strength
Charactcrist ics
lixpcrimental Sct - up Details of Impac~ 'l'cst on Mortar Slabs
.4 View of Experimental Set-up for Flexure Test of Mortar Slab
(with Data Acquisition system)
Stages of Casting Corrugated Sheets
Experimental Tcst Set-up for Various Strength Tests on Sisal Fibre
Corrugated Sliccts
Schematic View of Test Set - up for Flexural Strength of
Corrugated Sheet
Schematic View of Test Set - up for Impact Strength of Corrugatio~i
Schematic View of Test Set - up for Splitting Load of Corrugation
Schcmntic Vicw ol"1'cst Scl -- 1113 li)r Wnlcr --'l'igh~ncss
01' Sisal
I:i brc Corruga~ed Sheet
(xv i)

If Eg.
No.
I'agc
No.
Water Absorption of S~sal fibre Vs No of Days
( for two cycles of alternate wetting & drying )
Flow Values Vs Water 1 Blnder Rat~os of Flyash - Cement Mortar
(1:3; Flyusk =10 - 70%;kj= 0%; r =200)
Flow Values Vs Water H~nder Rat105 of S~sal F~bre Cement Mortar
Compos~tes
(I:; fl]'~\li = 0°4 ; I// = 0.2F - 2.0% ; r = 2/10)
I ION b"lIll~\ \\ w'l~~l'l3ll~llc1 I

Fig.
KO.
Ibage
No.
Flow Values Vs Cohesion of Sisal F~bre Flyash - Ccnient Mortar 282-284
Co~nposites
(I:. ;,/jlp(z\.lr
cotrtc~rt = 10% - 70% ; I/; = 0.2.56 - 2%; r. - ZOO)
1 low Vcilucs Vs Cohes~on ol'l lyash C'emenl \4orta1
(1:Q;Jlyash content = 10 - 70% ; Vf= 0%)
Flo~ Values Vs Cohesion of Sisal Fibre Cement Mortar Composites 285
(I:I;Jihre = 0.25 - 2.0% ;flynsl~ content = 0% ; r = 200)
Flo\v Values Vs Colics~o~~ of Sisal f'ibrc I:lynsh - Cement Mortar 286-288
~'olll~~o~lic\
(1:4 ;jlyrr\ir catrf~)nt = 10% - 70% ; I// = 0.25% - 274; r = 200)
Flow Values Vs Cohesion of Flyas11 Cement Mortar
(I:j;flyaslr = I0 - 70% ; VJ= 0%)
Flow Values Vs Cohesion of Sisal Fibre Cement Mortar Composites 289
(1:s; VJ-= 0.25 - 2.0% ;.fiijnsh cotifent = 0% ; r = 200)
Ilow L'altlc~ Vs ('ollc\toll ol' SISII I
Composites
~ h I ~ I~;I\~I-('CIIICIII
c
MOI~;II 200-101
(I:5 ;flyash content = 10% - 70% ; yf= 0.25% - 2%; r = 200)
Compressive Slrengtll Vs Fibre Content of Sisal Fibre
Flpash - Cement Mortar Composites at Various Ages
(1 :3; @ at consfant.flow vaIue;jlyasli content = I0 - 70%)
I~lc~i11;11 S[I.CII~[II VS I:I~>I.c C'OIILCIII 01'513~111'1bsc I~ljasli - Ccnicnl
Mortar Composites at Varlous Ages
(1:3; @ at constantflow value;fljlash content = 10 - 70%)
Split Tensile Strength Vs Fibre Contents of Sisal Fibre
Flyash - Cement Mortar Composites at Various Ages
(1:3; @ at corzstantflow value;/qyash content = I0 - 70%)
Impact Strcngth Vs 1:ibrc Contcnrs of Sisal Fibrc Flynsli - Cement
Mortar Composites at Various .4ges
(1:3; @ at constantflow value;flyash content = 10 - 70%)
Flexural Strength Vs Fibre Contents of Sisal Fibre Flyash - Cement
Mortar Co~nposites Slabs at Various Ages
(1:3; @ at constantflow va1ue;flyash = I0 - 70%)
licsidual Iliipact S~rcngtli Ration (I,,) Vs I:ib~-c C'onlc~irc of Sisal
librc 1:lyash - Ccmcnt Mortar C'omposilc Slabs
(1:3; Before andAfter exposure in Na0H;flyaslr content = I0 - 70%)
(xviii)

Fig.
No.
Page
No.
I Vs l"ii>~.c ('ii~itc~l~s i11' Sis:~l I'ih1.c I"lya.;l~
C:oiliposilc Slabs
(1:3; Before an& after Exposure in !V'aOH;flyaslt = 10 - 70 %)
('c~~ic~il~ bli~1~1;11~
Flexural Load Vs Fibre Contents of Sisal Fibre Flyash - Cement
&'lortar Composite Corrugated Sheets
(1:3; @at 28 dn.ys;flvash cotltent = 0 - 30%)
SpIi[tilig 1,o:icl Vs IPiLhrc ('o~~tc~its 01' Sisal I:it>~.c l.iyi\sli --
Moriar Composite Corrl~galctl Sliccts
C:CI~~CII~
(1:3; @ at 28 duys;flL.ash content = 0 - 30%)
Residual Inipact Strength Ratio (I ,, ) Vs Fibre Contents of
Sisal Fibre Flyash - Cement Mortar Composite Corrugated Shecls
1Vatcr. Absorptio~i \is t:itrc Contents of Sisal 1:ibrc Flyash - Ccmc~it
M~rt:lr COIII~OS~~C C:ost.~lg;~tcd Sheets
(1:3; @ at 28 days;flyash content = 0 - 30%)
Water Tightness Index Vs Fibre Contents of Sisal Fibre Flyash -
Ccmcnt Mortar Corrugated Shcets
(1:3; @ at 28 days;Jyash content = 0 - 30%)
Photo Showing the Sheared Specimens of the Composite
Fractured Specimens of Composites After the Impact Test
Fractured Specime~is of Composites After the Flexural Tcst Using
the 11npacted Specimens
l"1~1c1~1rcd Sptc,i~~i'~\s ;I(~L:I, I~~vi~Iti~~li~ig (lit 1)111~;1l>iliI~ (i[' \lie
Chmposilc by thc Impact 'l'csl
Fractured Specimens of Corrugated Sheet after the Impact Test of
Corrugations (Vl= 1.0%; Flyash = 0 - 30%)
Fractured Specimens of Corrugated Sheet After the Splitting Test of
Corrugations (I/'= 1.0%; Flyash = 0 - 30%)

CHAPTER 1
INTRODUCTION
1.1 GENERAL
Natural fibres, especially, coir, slsal, jute etc., have the potential to be used as
reinforcement in cement composites. In recent decades, there has been a growing interest
in developing countries. to develop natural fibre - based products for various applications
in Civil Engineering, especially, for use In buildings Such developn~ents have the twin
advantages of sustainable development, (as natural fibres const~tute a renewable resource)
and availability of biiild~ng materials at affordab!e cost. In spite of such advantages and
existence of a large potential, investigations on the suitability of natural fibre reinforced
composites for developing various building materials have not been that extensively
carried out and reported, which is true not only in India, but also in other developing
countries.
Two important reasons, rather, inherent drawbacks which are responsible for the above
scenario and which have to be addressed scientifically and comprehensively, and should
be overcome, if, the potential use of natural fibres have to find their much deserved place
in building industry, are : (i) 'balling effect' of the natural fibres, when incorporated into
the matrix, thus reducing the workability of the mix; (ii) 'embrittlement' of natural fibres
in the alkaline medium present in the cementlconcrete medium. From a critical review of
published literature on workability and rheology of cement/cementitious systems, it is
inferred that certain criticisms have been advanced against 'conventional tests' of
workability (like slump test, compaction factor,V-B time etc.) by Taattersall and Banfill
[l] like: (i) conventional tests for workability are 'empirical in nature' and they do not
measure the intrinsic property of the material; (ii) they do not have a sound theoretical
background and (iii) they do not give consistent results and hence pose difficulty in
comparing the performance of various mixes.
In view of the above, emphasis is on the use of 'two-point workability test' and on the use
of 'Rheometers' for studying the workability of cement lcementitious systems, in recent
years. In the case of composites, the only test standardized for measurement of workability
of fibre reinforced concrete (FRC) is the 'inverted cone penetration test'. However, there

is no test standardized in India for measuricg the '~vorkability and rheological behaviour
composites' Even the 't~o point workzbillty test' and 'Rheon~eters' which measure the
'yield value' (z ) and 'plestic viscosity' (p), have limitations s~ich as: (i) their use for
composites has not been esrabl~shed; (ii) they have not been standardized and they also
give inconsistent results, (iii) they are very costly, prohibiting their widespread application
in developing countries l~ke India.
On the other hand, certain tests like shear box test. tri-axial shear test and unconfined
compression test, which are widely used in Geotechnical Engg can measure inherent
properties [ie. cohesion(c) and angle of internal friction(cp)], of cement systems However,
such tests have not been used for the study of composites, especially using flexible fibres
like natural fibres, in wet state. From the foregoing, the necessity for investigating the
workability and rheological characteristics of natural fibre cementitious composites by
suitable tests, is established
1.2 KEED FOR THE PRESENT STUDY
Overview of studies carriedout so far on natural fibre composites in cement / cementitious
systems are summarized in Table 1 .l. Various methods adopted so far for improving 1
enchancing durability of fibres / composites in the different systems are summarized in
Table 1.2 and the various materials used in the cementitious systems of natural fibre
composites all summarized in Table 1.3. Overview of products i components developed
and investigated so far based on natural fibre composites are summarized in Table 1.4.
Based on the above, it can be inferred that the strength and other characteristics of (i) sisal
fibres have been investigated very extensively; (ii) matrix - modification is the preferred
method adopted to improve /enhance the durability of composites; (iii) studies on the use
of flyash in natural fibre cement composites and its influence on the various wet and
hardened state characteristics of composites, is rather rare; (iv) investigations on
developing roofing sheets / tiles based on natural fibre composites, has been the focus
among the products so far developed.
Of the various pozzolanas, flyash is abundantly available in several countries and also in
India. In spite of the above fact, it has been reported that the entire available produced
quantity has not been fully utilized, in spite of its proven beneficial use, especially, in
cement system. In India, sisal fibres are also abundantly available. Hence there is scope

and necessity to investigate the role of flyash in influencing the characterist~cs of natural
(sisal) fibre composites and products based on them.
Overview of workability tests adopted for cement systems and composites and to the
various cement mortar 1 concrete I composites for which the above tests are adopted and
investigated. are summarized in Table 1 5 and 1.6. It can be seen that studies on
ccmentitious composites are rather rare and that the 'mortar flow test' is widely used for
tht. workability studies of the composites The varlous methods i equipment used so far,
for the rheological studies (I e for cement systems and cor-i~pos~tes) and the various types
of mortar, concrete and composites so far considered for rlieological studies are
summarized in Table 1 7 and 1.8. From the above, it can be ~nferrcd that (i) 'rheometers'
are being developed and validated for the rheological studies on mortar and concrete; (ii)
conventional test like 'triaxial test' (~~sed in Cieotechnical Engg. investigations) has also
been used for rheological studies of cement concrete and that such studies are rather
scarce; (iii) there is no exclusive test available / developed so far for the rheological study
of cement composites (i.e, with natural / artificial fibres).
Hence, the relevance and applicability of siniple and conventional tests like 'box shear
test' to measure the inherent properties, of the cement / cementitious coinposites have to
be established.
In view of the foregoing, it is proposed to study the workab~lity and rheological behavoiur
of sisal fibre reinforced cenientitious mortar composites in terms of 'stability' and
'mobility', the various strength and durability characteristics, and to develop a product
based on the above composite.
1.3 OBJECTIVES OF THE PRESENT STUDY
Following are the objectives set for the present study:
(i) To study the chemical composition of a few natural fibres (in their native form
and after exposure in various alkaline mediums) and to choose the best of
them, based on their relative durability performance i.e, in the various mediums
considered, and which are also available in abundant quantities locally/in this
part of the region.

(ii) To study the dimensional stahiiity and waer retention capacity of the sisal
fibres.
(iii) To study the workability and rheological characteristics of the chosen fibre (ie.
sisal ) in cementitious mortar and composites for 1 :3, 1 :4 and 1 :5 mixes using
the selected test methods, namelyl 'flow table test' and 'shear box test', for a
range of fibre contents (0.25 to 2.0%) and flyash contents (10 -70%).
(iv) To study the strength characteristics of sisal fibre mortar composites
(i.e. compressive, split - tensile and flexural strengths). by suitable methods for
the chosen mix (1 :) and at various chosen ranges of flyash and fibre contents,
at early age ( 28 days) and at later-ages (i.e. 56 -130 days).
(v) To evaluate the impact strength ai',d the 'flexural toughness' of the
cementitious composites (1 :3) by a suitable method and to understand the role
of the chosen pozzolana and fibres in influencing the above characteristics of
the composites, at various ages.
(vi) To evaluate the durability of the cenlentitious conlposites (after 120 days of
normal curing and after 28 days of exposure in an alkaline medium) by a
suitable / chosen method and to understand the role flyash in influencing the
durability of the composites.
(vii) To produce sisal fibre reinforced corrugated sheets (in the laboratory
conditions) using cementitious mortar (1:3) and to study its strength
characteristics and performance and compare with a popular commercial
available corrugated roofing sheet, easily available in the market.
1.4 ORGANISATION OF THE THESIS
In Chapter 2, a comprehensive review of literature on a few rheological and workability,
strength and durability of cement I cernentitions systems of natural fibre composites and
products and characteristics of products using natural fibres, by various investigators, are
presented. An overview of methods and studies on impact and flexural toughness, have
also been presented.
Chapter 3 presents the preliminary investigations conducted on the natural fibres available
(in this region) for its suitability in the cement matrices. Characterization of the materials
used in this study, the mix proportions and test rnetl~ods adopted for rheological , strength,
and durability and products of sisal fibre cementitions composites, are also presented.

Chapter 3 presents the results and discussion of the abo~e study on sisal fibres
1 e rheologica!, wo;kabi!i:y. strength and durability of sisal fibre cementilious composites
and ma! fibre cementitious roofing sheets.
Chapter 5 presents the salient conclusions based on the above investigations and a few
recommendations from an overall assessment 1 usefulness of the present study.
References cited in this Thesis, are comprehensiveip listed at the end of the Thesis (in the
order of citation in the text).
Certain details of flyash (availability. composition etc.), methods of analysis of fibres,
novel testing methods and ~ts calibration and other testing methods adopted from the
various standards (i.e. IS) and sample calculations of various parameters used in this
study, are given in Appendices.

Note C Compressrve Strength F Flcruml Strength I Impacl Strength ST. Splrt- Tensile/ Tensile Strength FT~' F/e..uz~rai ro~ighncs.cl T(lziglnesr
BS Bondstrength, TO Torsronal Strength, LD Long- term Characterist~cs (creep, shrinkage), SC Seitlng Chat~arrerrsrics
fS/SC Plastzcs Shrrnkage Characferistics, TC Thermal Character~strcs (Conduclivrty, li~sulatron perfnrnlonce)

1
Table 1.2 : Ovenjiew of Methods Adopted for Improving 1 Enhancing Durability of
Fibres1 Composites
I""No.
/ 1
[
i
/
1
1 I
Type of Type of Method adopted (*)
Ref.
fibre system 1 2 3 1 4
No.
Sisal Paste
I 186,302,323
/ Mortar a a e e 245,253,254,301,265,365.
1 1 1 i 238
1 concrete
Q
ca c 1 5.270.275.236
Coir Paste
r 1 1 7,333
Mortar a e I 245,301,280,321,235.237
Concrete
Hemp,
Ramie and
Manila
Cellulose
San
Sun hemp
Jute
-
Malva
Concrete
Fique Paste
Mortar
, Concrete
I Paste
1 bagasse - Mortar
1 Concrete
'
i e ' 1 / 5,236
Paste 1 I I I
Mortar i I
Concrete
Pasle
e
184.228
1
1
I
Mortar
/ Concrete
I
Paste
------
Mortar
Concrete i e 197,277
Paste
1
I
Mortar
a
I 324
Concrete
1 I
Paste
I
Mortar
a 1 9
----
Concrete 1
Paste
I
I Mortar
0 1213 1
i
1
1 1 I I 1
Note: (*) - Descrlplion of Codes u as below
1 Carbonatton ofmatrix,
2 .immersion offibres in a slurry (SF, resin, silicate coatin@
3- Partial replacen~enl oj OPC wlth various poziolanas (inclzidlng natural pozzolanas / matrix
mod$catlonj;
4- Coating offibres bore sealrng, fibre impregnation with various chemicals, compounds - both
artificial and natural, lnciuding polymers)
I
i
1
225
I
I-
c 241
i
I

Table 1.3 : Overview of Materials Used in Cementitious Systems of Natural Fibre
Composites
S1. 1 Type of T~pc of ' Materials Used (" 1 Ref. 1
1 Yo. 1 fibre system / SL FA SF 1 R*)! 'IP No. I
I -
3
4
5
6
Paste
.
I s i . , 1 1 186,302,223 Mortar 0 0 245,265,253,301,238 1
1 Concrete
I
0 1 8
270,275,236.5
1 Paste @ I * ;
7,323
Mortar
. I * / . e
245,301,280,321,235,237
Concrete 1 I / 1 236
1 184.728 I
I
Mortar
Concrete I
Paste
i
I
i
Mortar
Concrete 1 ' e
I 197.277
Cell~~lose Paste 1 . 1 I
San
Hemp,
Ramie &
Man~la
Jute
I
/Vote:
SL - Blast Furnace Slag, FA - Flyash, SF - Silica fume, RA - Rice husk ash NP - Xatural
pozzolanas (Volcanic ashes - scoria andpumrce erc ,)
Mortar I
Concrete 1
!
Paste
------ Mortar
1
a
Concrete
I
1 @
.
1
!
I
I
9

Table 1.5 : Oveniew of '1Vorkabilih Tests Adopted for Cement Systems and
Composites
Sf. 1 System
No. I
i 1 Cement mortar
2 / Cement Concrete
I
hlcthod / Equipment 1 Ref. No. 1
Used
I
Slumn / 16
Flow table s~read / 26.33 1
, ,
Flow value 1 56,60,77,81,87
K- procedure / 62 1
K- Slump tester 1 13,14
Slump ' 15,! 9,20,24,28.32
3
Cement 1 Cementitious
Composites
(i) .Artificial fibres
75,79,80,82-86,88-92
Slump - flow
22,40,58,63,75.88
V-funnel flow / 22
Vee bee time iV- B) 1 23.6 1.65
Compaction factor (CF) 25,6 1,64,65
K- Procedure
62.63
Concrete : Slump
1 (ii) Natural fibres
1 Coir, Sisal, San, Jute
I 1
Concrete: CF, Slump, V- 276,277,200,207
-
B
- ort tar : Flow tea 1 181,235,238
1 I 1 mortar : Flow value 1

Table 1.6: Types of >lortar and Concrete Considered for WorkabiliQ Studies
1
I S1. S!stern
I Types
I Yo. I
I
i - 1,10nar 1 * Cement mortar ir( CM)
I
I '
1
/ * Flyash - Cement mortar (F-C-M)
Slag - Cement mortar (S- C -M) 1
* Uatural pozzolana - cement mortar (KP- CM)
!
L* Contro!led low strength materials (CLSMs) I
Cement - Silica fume mortar (C-SF- M)
I
1 * RHA mortar I
Concrete . Flowable concrete
i I
(FA 1 GGBFS I SF i MK 1
RHA and with / without SPs
*High - strength concrete (HSC)
1 1 1 *Alkali-activated slag concrete
1
3
1 *Under- water concrete
i *Roller- Compacted Concrete (RCC)
i *Ready- Mixed Concrete (RMC)
Composites ,
* Poly propylene
fibres
1 * Steel fibres 1
*Flyash - cement Concrete + SF
Cement Concrete
I
I

Table 1.7: OvenJew of Rheological Method / Equipment I.sed for Cement Svstems
and Composites
Si. / S stem- Method i Equipment Ref. No.
Used I 1
Rotational Viscomerer / 95 1
Rmokfi~ld Viqcntn~t~r 1 98 7
Vlsco - Corder 1 136,137
!
Co-axial cylinder / 138,140,141
I viscometer (Two- point 1
1 workab~!lty)
-
R ~ ~ c a m r t cUeotcat i -
D~rect (boy) shear test
2 Cement Concrete Two - point workabllit)
test 152,155,111.156.!58.163,
1 164-168,410 I
IBBIBML)
Mod~fied slump test
173,174,177
151
1 1 I Modified I Co- axial 1 98,154
1 cyllnder viscometer I
Triaxial tests (as for G T. 171,169,410
I I En@.)
Composites
Rheometer (BT RHEOM i 1 148.1 59,160,161.93.172, 1
1 Mortar: Direct (box) shear 181,235
I
Concrete:
Table 1.8 : Types of Mortar and Concrete Considered for Rheological Studies
1 System I Types
Mortar
: e Cement mortar (CM) (with I without admixtures)
/ 0 Mortar composed in consolidation free flowing (CFF) concrete
1 @Commercially available pre - packaged repair mortars 1
Concrete
0 Cement concrete (medium to high workability) with 1 without mineral
admixtures and SPs, and with and without vibration.
0 Consolidation free flowing concrete
e Self - leveling concrete
1 High - performance concrete (HPC)
/ Self - compacting Concrete (SCC)

CHAPTER 2
LITERATURE REVIEW
2.1 GENERAL
in this chapter, a brief review of general characteristics of sisai fibres, comprehensive
review of wet and hardened state characteris~ics durability characteristics and products
based on natural fibre composites are presented. Critical observations based on the work
reported so far, are also presented at the end of the chapte;
2.2 SISAL FIBRE CHARACTERISTICS
Even though four natural fibres were considered during the preliminary investigation
(namely coir, sisal, jute and hibiscus cannebinus only sisal fibre was selected for
comprehensive experimental investigations as reported in this only. Hence, a brief review
of salient characteristics is focused only with respect to sisal fibres, in this section.
2.2.1 Classification
-4 great number of fibre plants are exploited for their ability to yield fibres directly from
their wild or natural form, particularly in developing countries. While a great number of
species are employed in fibre production, relatively few species show high quality, good
yield and hence are of commercial importance. Fibres of economic importance are
members of various botanical families, the more exploited of which include
Amarilidnceae to which sisal (Agave sisalana) belongs. Several varieties of sisal exist in
different climatic conditions and with different morphological characteristics.
Classification system of vegetable fibres, is based on various major aspects, such as ,
(i) final uses (end - use of fibre in commercial terms) such as, textile fibres, bags &
canvasses etc., (ii) anatomical origin of vegetable fibres, such as, bark fibre, leaf fibre,
fruit fibre and root fibre and (iii) chemical origin (cellulose - producing fibres, ligno -
cellulose - producing fibres). However, the principal classification of fibres are based on
their origin in the plant [2].

Sisal is a bast fibre, u.hici.1 is extracted from the leales ofAguvu ~~.VUILILIU and fibre content
generally may not be more than 4Oio of totai leaf mass. Ei.
57 species known to date 131.
is reported that there are
2.2.2 Production and ejses
The main producers of .sisal fibres, in general, are: Brazil, Indonesia and East African
countries (like Tanzania). It has been reported that the annuai production of sisal fibres is
about 600 million tonnes (M.T.) [4], out of which Brazil alone accounts for nearly 220
M T. [3]. However, the production of sisal fibres in India is reported to be about 3 M.T.
only [4].
Generally, the fibres are used in the fabrication of cordage, strings, twines and ropes and
the fibres of low-quality are used as fillings in furniture and in the manufacture of paper.
Sisal is among the hard fibres of the World and represents around 70% of the World's
market in fibres. Its principal use is in the manufacture of sacks and its special use is in the
manufacture of marine strings due to its resistance to salinity [2].
2.2.3 Size, Structure, Chemical Composition and Properties
Size
Sisal fibres vary in size, between 6 -10 cm in width and 50 - 250 cm in length, depending
on species, climate and soil in the plantation. According to producer's classification, sisal
firbes are divided into three categories depending on their length as : (a) short fibres with
length 3 600mm; (b) medium sized fibres with length in the range 600 -700mm; (c) long -
sized fibres with length in the range greater than 700mm. The fibre diameter is generally
reported to be less than 0.2m1n 13: 51.
Structure
In general, fibres from different sources, age and parts of plant, have different structure e
and hence different properties. Sisal fibres are built - up of about 100 fibre cells (with a
length of 2- 5 mm) in cross section. The fibre cells are linked together by means of middle
lamellae. The fibre cells consist of a number of walls built - up of fibrillae. In the outer
wall (primary wall) the fibrillae have a reticulated structure. In the outer secondary wall
(Sl), which is located inside the primary wall, the fibrillae are arranged in a spiral with a

spilal angle of 40°, in relation to the longitudinal axis of the cell. 'fhe iibrillae in the inner
secondary wail (S2) have a sharper dope, 18'. The innermost wall (the tertiary) wall is
thln and has 2 reticulated arrangement of fibriiiate. The fibrillae are, in turn, built - up of
micro - fibrillae with a thickness of about 20 nm. Fig.2.1 presents a schematic sketch of a
fibre cell [S].
Vegetable fibres, in general, are mainiy composed of cellulose and lignin, although a
number of minor components, such as, wax, pectln. inorganic salts, nitrogenous
substances, colouring matter, etc. are also found In them [j, 61
About 65% of sisal fibre consists of 'cellulose' (a natural polymer) which occurs in the
micro - fibrillae, with a thickness of 0.7 nm and a length of a few pm and the degree of
polymerization being about 50,000. Hemi-cellulose (about 12%), consists of
polysaccharides, mainly xylos, with the degree of polymerization in the range of about
50 - 200. The hemi -cellulose mainly occurs in the outer layer of the fiber cell wall, in
other words, in the primary wall, and in the middle lamella. The hemi - cellulose in sisal
fibre has an acid character. Lignin (about 10%) mainly occurs in the middle lamella. The
middle lamella contains 70% of the lignin. Fibres or cells are cemented together in the
plant by lignin. The chemistry of 'lignin' is not yet completely understood, but, it is
known to be an amorphous and heterogeneous mixture of condensed aromatic polymers
and phenylpropane monomers. Lignin is classified according to its main building blocks
(guaicyl, syringyl etc.). The exact lignin composition is influenced not only by species, but
also, by other factors, such as plant's age. Pectin (about 1%) occurs in the middle lamella
and probably has a cohesive function. In literature, larger variation in the chemical
composition is reported, which is partially due to differences in chemical analysis
technologies [5, 71.
Chemical composition of sisal fibres as reported by various investigators are summarized
in Table 2.1. In the above Table (i.e. Table 2. l), chemical composition as reported for sisal
fibres by Brazil and fibres from various regions in general, are given.
Physical and Mechanical Properties
It is well known that the physical and mechanical properties of these fibres are affected by
environmental changes, e.g., soil, time of harvesting, process of fibre separation,

treatment, air - humidity, temperature etc. Various physical and mechanical properties of
sisal fibres, as reported in the literature are summarized in Table 2 2. Vegetable fibres in
dry state have a tendency to absorb very high percentages of water. when they are actually
immersed in water. Sisal fibres are no exception to the above behaviour. Moreo~er, such a
behaviour becomes critical. as it may a effect the performance of cement - based
composites, due to the artificial inducement of lower effective water - cement ratio in the
matrix. Data as published in the literature on the water absorption of sisal fibres (of Brazil
origin) during 24 hr. of immersion in water (at roon: temperature) is given In Table 2.3 [8].
It can be seen that the first 15 - 30 minutes after lnlmersion of fibres, are crucial. as the
water absorbed is very high, than in subsequent periods.
Lumen 0 1 1 pm
Tertiary wall
Inner secondary wall S2
Outer secondary
wall 0.7 pm Sl
Primary wall
Fig. 2.1 Schematic sketch of a Sisal Fibre Cell [5]
2.2.4 Decomposition of Sisal Fibre in Alkaline Environments
Gram [5] was the first to perform a systematic and comprehensive investigation on the
durability of sisal and coir fibres in a cement matrix; (i.e. embrittlement) to suggest
mechanisms responsible for decomposition of sisal fibres in alkaline environments and to
investigate the effect of various counter - measures. It is generally held that the
decomposition of cellulose in an alkaline environment can take place in accordance with

tmo different mechanisms. One is tine 'pealing - ofi' mechanism which occurs at the end
of the molecular chain, which is considered fairly harmless, until a temperature 75" C. The
other form of cellulose decomposition consists of aikaline hqdrolysis, lxhich doesn't take
place at a high rate, until the temperature is in excess of ! 00".
'floweter, the peeling - off mechanism becomes the dominating decomposition
mechanism, in the case of hemi - cel:ulose, in an alkaline environment. Lignin, which
consists of aromatic substances, is easily broken In an alkaline environment. Hence, the
prlmary cause of the change in the characteristics of sisa! fibre (in concrete), as assumed
by Gram [5], is due to chemical decomposition of i~gnin and hen11 - cellulose present in
thc middle lamella. The alkaline pore eater in concrete dissolves tlie lign~n and hemi -
cellulose and thus breaks the link between the individual fibre cells Hence. a long sisal
fibre loses its reinforcing capacity in concrete, as it is broken down into numerous small
units, as shown in the schematic sketch i.e. Fig. 2.2.
Currently held view is that the durability problem is associated with an increase in fibre
fracture and decrease in fibre pull - out due to a combination of weakening of the fibres by
alkali attack, fibre meneralisation on due to migration of hydration products to lumens and
spaces and volume variation in these fibres due to their high water absorption 181. To
enhance the durability of vegetable fibre reinforced cement - based composites, especially
that of sisal fibre cement composites, several approaches have been studied including:
(i) fibre impregnation with blocking agents and water - repellant agents, (either singly or
in tandem), (ii) sealing of the matrix pore system; (iii) reduction of matrix alkalinity
(i.e. through change of binder /using pozzolanas); (iv) combination of fibre impregnation
and matrix modification and (v) carbonation of matrix [8].
Blocking agents such as , sodium silicate, sodium sulphite, magnesium sulphate, iron or
copper compounds and barium and sulphate salts; impregnation of sisal fibres, with
organic compounds derived from timber, such as, tannins, colophony and vegetable oils;
reduction of matrix alkalinity through change of binder i.e. using high - alumina cement;
gypsum cement, slag; cement and using pozzolanic materials such as, flyash, silica fume,
blast furnace slag, natural pozzolanas such as rice husk ash (RHA), pumice, diatomite and
scoria powders; immersion of (sisal) fibres in slurried silica fume, have been used studied
for improving the durability of sisal fibre cement - based composites [8, 5, 91. However,
the best results, in general have been obtained when cement was partially replaced by
pozzolanic materials in sisal fibre composites.

Table 2.1: Chemical Composition of Sisal Fibres
Note (*) -for Bruziijibres, (**I - Getierul &,froui t'ur!ors sources
Table 2.2: Physical and Mechanical Properties of Sisal Fibres
'
No.
1 Diameter (mm) 0.08-0.30
I , (gicm3j I I I
1 3 Natural 10.97-14.44 NA I NA NA / KA I UA
I content (%)
/ 4 Water 67- 92 N A N A
1 absorption ,
after
j
5 min. I 1
I under water I
1
1 (%I
~
190-250
I :;tion
N A N A N A N A N A
to saturation
(%I
6 Tensile 227.8 -1002.3 363 568-640 530 - 640 568 280- 370
-.-
strength (MPa)
7 Modulus of i 10.94 -2670 I 15.2 9.4 - 15.8 94 - 22.0 26.5 13 - 26
/ elasticity (GPa) 1 I
13.0 3 - 5
I
Note: (i) (*) Indicate values exclusivelyfor$bres of Brazil.
(ii) Other values are applicableforjbres from various regions.
(iii) N.A - Values are not available / reported in the cited literature.
Table 2.3: Water absorption of Sisal Fibres
I Fibre I Water absorption (Oh wt.) at
Sisal
Smin.
89.3
15min.
88.4
30min. 1 1 hr.
94.7 / 95.4
4 hr.
97.0
8 hr,
96.8
Note: Values arefor sisalfibres of Brazil. [8]

2.3 STUDIES ON U1ORI64BIkITP: OF CEMEKT / CEhlENTITIOUS SYSTEMS
AND COMPOSITES
2.3.1 Workability - Definition
.Workability' of according to ASTM C 125 is defined as 'that property detemining the
effort required to manipulate a freshly mixed quantlty of concrete with mininlum loss of
homogeneity'
ACI Commlrtee 309 has defined 'Workability' as 'that property that
determines the ease and homogeneity w~th uhich it can be mixed, transported, placed ,
compacted and fin~shed' 111 otlic~ words, 'worhabil~ty' IS a qualitative term encompassing
the properties such as
'flowab~lity', 'compactab~l~t)'.'stablllty'.
'finlshab~lity',
'pumpability' etc. Moreover, ~t is not an inherent or a fundamental property of material
(i e. concrete/mortar).
2.3.2 Review of Earlier Works
It has been reported in literature that there were more than 100 test methods developed
during the last century. After screening for the obsolescence, 61 methods of workability
have been considered, for critical evaluation and development of any new workability test
by Koehler and Fowler [lo]. Moreover, a comprehensive view on the test methods and
apparatus used, the basic principle involved in the measurement1 equipment etc, for 26
methods, has been reported by Bartos and others [l 11.
A comprehensive review of reported literature till date has been carriedout to identify the
method adopted and the properties investigated for cement I
including composites, which has been summarized in Table 2.4.
cementitious system,
2.4 RHEOLOGICAL STUDIES ON CEMENT / CEMENTITIOUS SYSTEMS
2.4.1 Rheology -Definition
'Rheology' is defined as 'the science of deformation and flow of matter' [3.38], which
means that it is concerned with relationships between stress, strain, rate of strain and time.
2.4.2 Study of Rheology - Background Information
During the late seventies and in the early eighties the study of 'rheology' as applicable to
concrete was identified, initiated and comprehensively investigated by the pioneering
efforts of Tattersall and then closely followed by Banfill, as evident from two excellent
books published by them [I, 121. From then on, the above area has been explored fairly

estenslveiy by various investigators, leading to the deveiopnlent of over half - a- dozen
rheometers for studying the rheological behaviour of cement systems. The focus 01-1 the
rlieological studies on cement systems for the past 25 years, is due to the identification of
several limitations and advanc,ement of criticisms towards conventional workability tests,
which are still adopted, in spite of the fact several developments, some of them being
unique, have taken place in concrete technology.
The malor criticisms that appiy to a11 empirical tests of workabil~ty, including those
incorporated into various International and National standards can be summarized as
follows [I]:
(i) They are all 'single-point tests', i.e. in each test only one measurement is made and
the result is quoted as a single figure. The practical outcome of this deficiency is
that a given test may classify as identical two concretes that are subsequently
found to behave quite differently on the job;
(ii) All the tests are 'operator-sensitive'. In other words, the tests give results which
depend on the dimensions and detailed arrangement of the apparatus and in many
of them the result may also be influenced by minor variations in the technique of
carrying out the test.
(iii) None of the tests is capable of dealing with concrete of whole range of
workabilities. For example, 'slump test', which is the most commonly used test is
quite incapable of differentiating between two concretes of very low workability
(zero slump) or two concretes of very high workability (collapse slump),
(iv) Most of the tests are quite arbitrary and empirical, or at the best, have only a
sketchy and doubtful theoretical basis.
Realising the inherent limitations and criticisms of the various 'empirical tests', efforts
were made by various investigators, the pioneers in that being Tattersall and Banfill [I]
who have stated in categorically terms during 1980s, the property known as workability
should be rigorously defined, in terms of physical constants, derived from the fundamental
quantities (mass, length and time), either directly or through other quantities (such as
stress and shear rate) based upon them. Moreover, such physical constants should describe
the material itself and do not depend on the circumstances in which the material is tested
or used [I]. The above effort culminated in the development of 'rheology' of concrete,

n:ortar and pastes and In tkt. development of var~ocs rl~eometers 2nd in the development of
'two-polnt tests' for the \vorkabElity by Tattersall and Banfill [I]
2.4.3 REVIEW OF RHEOLOGICAL STUDIES
(A) Overview of Studies
A comprehensive review of rheological studies caniedout so far by various investigators
on cement 1 cementit~ousystems (covering cement paste, cement slurries, cement grouts,
cement mortar, cement concrete) has been carriedout to identify the objective and
equipment used in each study. The above review has been briefly summarized in
2 5 to 2.9
(B) Critical Observations
Tables
Based on the overview of rheological studles given in Tables 2 5 to 2.9, cewaln critical
observations can be made, as under:
(I)
(ii)
(iii)
(iv)
(v)
(vi)
Most of the studies were based on development and use of rheometers;
Development of rheometers were confined to a few select countries;
Emphasis is on studying the rheological characteristics of concrete / paste, and
that reported studies on cement / cementitious mortar were far less;
No study has been reported for either cement composite or cementitious
composite so far, especially for flexible fibres like natural fibres;
Apart from the use of rheometers, certain other testing methods, like direct
(box) shear test and tri - axial test have been used for the rheological studies
either for cement systems i composites, in recent decades, after the
development of rheometers, say, after 1980s and
The applicability, reliability of the above tests [ as in (v) above], especially for
natural fibre composites, have not been attempted and reported.

p- -
-A
Table 2.4 : Overview of Workability Studies on Ccment / Cementitious Systetns
-
s1
No. -
1.
-
2.
Author / (s)
Al-Manaseer,A.A.
Nasser, K.W.
XU,~.
Chung, D.D.L.
Year - Cement1 Cementitious
system considered
Flowable concrete with
superplaticizer (SP)
with similar wlc ratios.
Flowable concrete with/
without SP, made with
different w/c s.
-
~igh-workability
Concrete.
Cement mortar of high
workability.
Blast furnace slag paste
activated by NaOI I and
Na zCO3.
---
Workability method
adopted - -
K - slump
Slump, slurnp flow and flow
tests on a range of concretcs.
Slump (ASTM C143-90 a
method).
6. 1 Duva1,R. I HPC concrete using I Slumv values (mm)
I Kadri, E.H. I 1 silica-fumc as an - I
Properties ctc. investigated
Mini-slump test using mini- I ~Workability
slump cone mould (Top dia.
==19mm; bottom dia. = 38mm,
height = 57n1m) as reported
I by Kantro[W-61
-~
- --- --
.Consisteilcy and workability of concrete
wtth and without SPs, but, with slmilal
W/C' 7
oConsistency and workability of
flowable concrete
oTo provrdc practical reconl~nendations
on thc effectiveness of K-Slump tester, to
mcasure the aboxropcrties.
---- --
eWorkabili~y of hrgh performance and
high workability, especially 'fluidity' of
concrete is estimated.
oworkability of cemcnt mortar mix in
tenns of slump (mm) using silica fume
(as rcceivcd and surface trcatcd with
( island coupling age17t) as a1 admixture.
-. -.- ---
of pastes (of slag)
I I admixture. plasticizer (SP) to maintain fluid
consistency olconcrete and to deterntine
the dosage of SP based on pre-
-
\ -,
of concrete with super-
- determined slump (range) value.
7. Baskoca, A. I I Concrete, especially I Slump values (mm) oi
--
[EX--
No.
.- - .
13
... Contd.

No.
Author/ Year (
-
etc. irlvcstigated me;.- 1
Cement/ Cemcntitious I Workability method - ~Y~operties
system considered
Ozku1,M.H. I RMC using - various %n% admixed of, to understand the
Mirma S.
admixtures (one concretes with time and after influence of various chemical
retarder; two water agitation1 retempering. admixtures.
reducing .- admixtures).
S hirkavand,M. Cement silica paste Flow table test for mortar
Raggou, R.
withlwithout SPs. (RS 1881 : Part 105: 1984)
Khayat,K.H.
Krstulovic,P.
Kamenic,N .
Popovic,K.
Chan, S.Y.N.
Teng,N.Q.
Tsang,N.K.C.
Bai,J.
Wild,S.
-
1994
1996
1999
-
Self-consolidating
concrete (SCC).
--
Cement mortar and
concrete with various
fillers (limestone,
pozzolan)
High -strength arid
superplasticized
concrete.
~oncreCecontainin~
.Workability ofcement-silica paste in
tenns of (high) fluidity of the paste,
using the test procedure for mortar, was
adopted.
eTo deteinlinc SP dosages which offkr
high fluidity for pouring into rnoulds for
auto- claving and that voids are
nlinim~~m, as to vey lligll strc~~gtl~s :------
Slump- flow and ~%&lcl eSiump flow tcst to evaluate liee
flow tests.
deformability in the absellce of
obstructions and V-fu~mel flow test uscd
to assess spread of concrete tl~rough n
restricted arca without blockasc.
..-
-. -. - - . -
~ebe lime (for- concrete) and - *Workability of ~llortar and concrete.
flow table test for mortar)
were adopted.
Slump test (as per
RS 188 I :Part I02 ; 1983)
factor
oworkability and loss in workability of
concrete in tcrrns of slunlp and slumploss
evaluated on various types of SPs,
especially by the use of a new type of
admixture-CFA (carricr fluidifying
agent). -- --
.To assess the potential of utilizing PC-
PFA-MK blends in the production of
p~
-- --
- .- . . --
- . -. --- .---- -
23
2 1
2 :!
2i I
. - .--
2 5
I
- - ~
I
41

.
I"=
Cement/ Cemcntitious
13
14.
15.
Sabir, B.B.
Paya,J.
Monzu, J.
Borrachero,E.
Peris-Mora,E.
Gonzalez-Lopez,E
Hsu, K.C.
Chiu,J-J.
1996
1999
I --
Wakelay, L.D. 1987
system considered
replacements of OPC.
-.. -
Flyash-cement mortars.
Workability of cement
paytes and concrete.
Salt-saturated concrete
Workability method
adopted
were performed.
-. -----
Flow table spread (F1'S)
(i)Spread diameter on a
vibrated sprcad tablc for
cement paste.
(ii) Sluinp of concrete with/
without SP
-.
Slump (ASTM C 143-78)
Properties etc. investigated
-- - -- -
IIPC.
-To establish optinlull ranges of blends
for concrete which will give practical
workability ranges. --
.
-Workability of flyash-cement mortars
containing flyashes of various forms
(ground l~ingrounded)
e7.0 determine the influerlce various
flyash processing metllods.
_
.Fluidity of cement paste and
workability of co~lcretc in Lernls of' slump
value were tletcrrnined
-Effect of addition time and SP content
on the above properlies (fluidity/slunip)
of pastes/concrctc determined
.Absorption bchaviour of'thc type ofSIJ
used has been asccrtaincd / quanti tied.
~
.Workability in ternls of sltirnp was
determined for salt-saturated concreted
with 0 5% citratc (a retarding aclmlxture
for sulphatc phases - licmiliydrate and
-
Ref.
No. -
p~~
26
Superplasticized
concrete
.-
Slump and Slump-loss with
tiine.
gypsum) -. -- -- .____..
.Workability ln terms of slump value aid
slump-loss w~th time for various dosage
levels of a new SP (a high niolecular
weight sulponaphalene condensate) were
st~idied to determine the dosage without
significa~~tly affecting strength ~
. . . Contd.

1999 Alkali-activated slag Slump and slump-loss wrth
concrcte.
timc.
1999 Aklali -activated sag Slump and slump - loss with
concretes ultra-fine time.
materials
1993 Flyash Mortar Flow Table Spread 'Test -
--
Properties etc. investigated
nronerties.
.To study alkali activation of two types .
namely, (i) sodium hydroxide In
colnbinatlon with sod~um carbonate and
(11) wdrurn silicate in combination with
hydratcd lime and to achleve reasonable
workability and equivalent onc-day
strength to l'ortland cement concrctc at
nor~nal curlng temperatures
eSlurnp and slump-loss of the above
concrete werc determined and compared
wrth POI tland cem
-- --
ePerforrnance of a
(AAS) concretes contarnlng part131
replacement of slag (as bl~lder ) with
CSF ultra finc slag (UIS) and ultra finc
flyash (IJFA) wlth ertlphasis on
achieving equivalent one-day strength
and compaiablc workability with that of
OPC concrcte. -
~Workabllrty in terms of slurnp value
wcre dcterrnlncd for cement concrete
with three types of ccnlent and ASI'MU
494 Type F superplasticizcr (comlnerclal
type) along with compressive strength
were investigated
compatibility of SI' with cement
Kef.
I No.
-
-I-- -
-- fractions -- on - 33 --
... Contd.

~
-
s1
No. -
Author / (s)
Paya, J.
Monzo, J.
-
21. Douglas, E.
Bilodeau, A.
Malhotra, V.M.
-
22. Gifford, P.M.
Gillott, J.E.
-
23.
Wainwright, P.J.
Rey, W.
Tomisawa, T.
Chikada, T.
Nagao, Y.
Cement1 Cementitious
system considered
Alkali- activated slag
concrete
Activated blast furnace
slag cement concrctc
(ARFSC)
GGBFS concrete
GGBFS concrete
Workability mettlid
adopted
Slump
Slump
Slump
Slump
-.
. -
-- - -.
Properties ete. investigated
flyash mortar studicd
*Workability in terms ITS were
determined for 4 sized fractions anti In
original form, for replace~nent levels 0 -
60%
-. --.-----. . ----- - --
oGGHFS was activated wlth sod~urn
silicate to detern7ine its properties and
durability
*Properties i11 wet state and varlous
hardened state were determined to
u~lderstand their behaviour and help in
widespread applicallon In the
c~.str~ct~~ind~~.s~ ... -.
sARFC were prepared using aggregates
fi-om six sources in Canada
oAAR and ACIl wcre studies and
com~aredwithOPC. . __- . -..
eGGRFS obtained horn a number of
sources and used in concrete
-55% and 85% of'OI'C were replaced by
GGRFS.
-Slump and bleed test conducted on
above concretes to understand the
influence of additions of CiCil3FS.
gI3igh fineness of GGRFS used in large
quantities with super low heat ccmerlt
(sL,r3c)
*Heat of hydratiol~ of ~- SLIIC (available i
... Contd.

S1 I Author / (s) I Year / Cement/ Cernentitious
27
El-Khatib, J.M
Sirivivatnarnon,V.
-- - - -- - --
Blended cement
Concrete
1997 Blended cement
I Mizobuchi,T. I I IISC
I
Yurugi, M.
Faruya, N.
concrete (with large
Yarnaoka, R.
amount of BFS and FA)
29. I Swarny, R.N. 1 1990 / Slagconcrete
I
1992
UscofRFSandSFin
.- - -
Workability
adopted
Slump
Slurllp
--- - -
- - - - -- -
Flow flow for mortar with and
without slag.
Slump
Slump
PI-operties ctc. investigated
-.
Japan) is 167KJfkg (428 days and 30
MPa compressive strength @ 28 clays
*Effect of fineness and content of
GGBFS on hcat of l~yd~ation etc studied.
-- -- -- -
.Blended cement co~~crcte (OP

-
Sl
No.
Author / (s)
) ' " ~ " " ; G ~ ~ ~ ~
concrcte
Slump
31. Sakai, K.
Watanabe, H.
Suzaki, M.
Hamazaki,K.
1992 Blended cement
concrete (i.e. OPC +-
GGBFS or FA)
Slump
33.
34.
Ozyildirim,C.
Saricimen, H
Masiehuddin,M
Al-Tayyib, A.J
Al-Mona, A.J
1994
.-
Slag cement
concrete/cement - SF
1995 Flyash-ccment concrete
Slump (ASTM @, 143)
Slump
1-
--
- - - - -- . -
I'roperties etc. investigated
-- .
durability .--.-.
investgated. -. -..-. - . - .
01High-volumes of GGBES were
incorporated (i.e.7596) into concrctc and
dense, low W/B ratios and good
workability produced iising SP.
- - -- -~---- ~- ~
-1Jigh- volumes of GGRI;S/ FA arc
il~corporated and blended cement
concretes prepared (range of CiGHI-'Sf
FA used 30 - 80%) for production of
low-heat concrete tbr mass coricrctirtg
purposes.
-Strength and durability studies
carriedout, apart fro111 tests on wet statc.
cconcrete containing GGBFS from
Sparrows poiilt, Maryland, was
investigated
-Workability. strength characteristics of
actual production material investigated
and repo~-tcct.
- .
*To use maximum arnotlnt of slag and
minimum of silica fume in concrete that
would yield concrete with satisfactory
stre~lgth and .- low_pem~eability. ---- .- -
sl'o use 30% of FA in concretc
workability based on slulnp value
stipulated as one of the design
parameters
*Effect of curing regimes on

.
P
Sl
No. -
-- - - -
Author / (s) Ycar --cement/ Cementitious Workability rncthod
system considered adopted - - -
Wain Wright, P.J
-- --
--
1996 Slag - OPC concrete Slump
Tolloezko, J.J.K
Brooks, J.J. 1992 Slag- 0~6oncrete Slump
Wain Wright, P.J
I Boukendakji, M.
37. 1 Nakamma, N.
Sakai,M
Swarny, R.N.
on stre~lgth etc
eEifect of finenesr of \lag on strength
arid mtcrostt-ucturc of slag cement
concrete
-- - --
~Effectiveness of 'SCM' IJI controll~np
chlorlde - pcr~etr - ation - -- - -
eHehaviour or' concrctc under marlnc
Concretc with SCM Slump
Laiw, I.C.
/ Concrete I Slump I
Mark, G.A.
Ih(iii 1986 Slag-cemcnt concrete Slump
I I I I reducing chloride ion ingress under I 1
I -- -. --. --- -- --
marine cnvtronr_llerr
I
-- -- -- - .
pp
lTikngat, P.S.
1 1995 ( Concretc with FA/
-Cl,loridc binding in concrete cont;iinina 1 54 i
I 42 1 ~olle~, B.T.
GGBFS/SF
SCM. iindcr sea watcr c;_posnre.
Domone, P.C. I 1995 Iligh-strength concrete Slump
-Properl~es of concrete containing 1'1:A
Sontos, M.N with PFA and GGBS in high - strength concrete.
-- -- - -- -
43 Hirai, K. 1 ---I
Slag-Cement ~ oTar Flow (in mm) cIn~provcme~lt of' durability of ce~nent
tnortar made from nco-ferrite cement
incorporating three different mnounts of
I
Futudome,K
Slump
Miyano, k
furnace slag was
1 aniguchi, H. placement from
Kila, T.
- -- -- ST
- ____ - --A_-

_- --- --
( S1 I Author / (s) I Year 1 Cement/ Cementitious I Workability method 1 Propcrtics etc. investigated
-
adopted
--
Slump test (ASTM C 143)
~lcat-tcst (ASTM C 187)
Flow test (ASTM C 230)
Penetration test (Dm 1048)
Flow test (Dm 1048)
Remouldlng test (ONDRM B
2303 - Austrian Standards)
K- Factor
Compact~on fjctor test
-- - -..-
V-H and compaction factor
test
-Modified compaction factor
test
Powcr required vibrating
mixes of low W/C, undcr
standard conditions used to
colnpare workability.
- Defom~ability meter
(developed by Swedish
Cement and concrete
Research Institute)
~Iielatlon between consistence and six
methods of concrctc established that
water content of concrete is parabol~c
eCo~lsistencc values duc to change of
water content can be pred~cted with I

I S1 I Author / (s) ]

:I- /
Author / (s)
Year
-- --
Cement/ Cementitious
system considered
--. -
Workability method
adopted __ --_-
- pp
I
Properties etc. investigated
-. - - --
with SPs.
/ -1ritc1mitterlt and continuous rnorst
Ref.
No.
Duval, R.
- --- -- -
%lump and Slump flow (112
r 1m-1)
-
Slump
accurnulatcd heat In I-IPSs
0 10- 30% of OPC replaced wrth Sb ancl
W/B ratlo 0 25 - 0.45 ~~sed along wtt11 a
I
Takagi, N
Horikawa,S
High-strcngth silica
fi~me concrete
--.- - - -. --
Normal and highstrength
concretes
containing metakaolin
(MK)
RHA- mortar
Flow
SI', for all IIPCs -- --- -- --
sShr~nltage characteristics of 111g1-1
strength s~llca fume concrctc wcrc
detcrn~i~led by autogencous shrinkage
and drying shrinkage tests a t 7/28 days.
I
-W/B ratios ranging from 20 -- 50% and
SFs 6 - 156 wcrc used.
-.--- --- - . --.- --
mMecl~arlical properties and chloride
penncab~l~ty of normal and high -
I -
+-
strength concretes (I-ISCs) containing
'MK' were studied
-Effect of'acldition of MK (5% & 9%);
typc of cenlent (2 types); type of curing
(moist / hot water) and age (1 to 90 days)
/ 017 fi-esh / hardened state properties. were
invesxag. -
*l-'iocess technology and production of
- I RI 1.4 based mortar and strength
... Contd.

Table 2.5: Overview of Rheological Studies on Cement Paste
Sl Author/ (s)
- No.
1. Zhang, X.
Han, J.
-
.+=I-
-
Year / Objective of the study
2000
- -- - - - - -- - - -- - -.
---. - --.-.
.To control and improve the rheological -Rotary duplex cylinder viscometer (from
property of the fresh HPC; the effect of ultra K.K.COII1,X) used to obtain yield stress,
and fines on rheological property of ceme apparent viscosity and rhcologtcal cun:e oI'
nt was studied.
--
1 cemellt paste.
--.
*Rheological studies on the efCect of super- I -Rhcoloical measui-emcnt ca~rled out uung
Front,K. 1 plastizer(SMF type) on the propcrtics of flyash I rotational viscon~etcr type viscotestct V 1 050 1 1
I I suspensions, containing small quantities of 1 (Haakc). I ]
Nessiom, A.A.
cement, lime and gypsum.
-
viscometcr specially designeci lsor
used
- -
'15
Jones, T.E.R.
Taylor, S
mortar and cement concrete
.- --- --- -
Bulhley modcl \vas ~lsccl for thc
stress and strain rate for cemcnt pastcs and to clnpirical *nodel
compare with experimcnts.
I

-
S1
No.
Author/ (s)
I
14 I Yongmo, X
O'kcefe, S.J.
ThurairatnamJ 1
Ziming, W.
Daneng,I-I.
Y aosheng, X
Year I
Objective of the study
.-
-- - --
a-
products of alum~natc hydl-atlon
phase on theological behaviour of cylinder and
cement pastes with regard to the influence of
hydraulic reactivity of C3 A and the demand for
sul hates resulting from it.
--t
1990 *Relationship between microstructure and
rheology of cement pastes wcre investigated, -
-- .-
1990 .To study the rehological behaviour of fresh
cement pastes modified by the add~tion of a
stabilizing and surface active (SSA) agent and
polymer latex particles, at a constant water:
solids ratio.
obtain correlation/relatio~lship bctwcen
carly agc property of threc cement pastes (OPC,
Oil-well B, and high alumina) mcasurcd by a
range of tests (penetration resistance , vicat
setting , isothermal calorimet~y and ultrasonic
pulse velocity) with loss of fluidity and setting
of cement paste or grout.
-. - -- ---.
systematically the rheological
properties, stability and groutability of ccmcnt
Equipment/method used
Rv -2 uslllg dcv~cc I I
- -- - -- -
-- - - - - -- -.
-NXS - 11 coaxial cyli~ldcr \~lscometer was
uscd.
- ------ ---- - .
0 IUxologlcal techniques used were stress
relaxation after sudden stsalt1 and constant
frequency o\~rllat~on.
A Bohlln VoK rhcomenter (13ohlin Rcologi,
UK Ltd., 1,etchworth) with co~~cci~trlc
cylinders geomctry, was used.
r Hclical inipcllcr vlscomctcr was i~scd to
obtain torque \vlth tlmc (aftcr n1isi11g in
minutes).
0 Early age properties were obtained by
conventional lcst set-ups.
oRotati11g coaxial cylinder viscometcr NXS- I 1
was used for measuring the thelogical
panleters of cement pastes with w/c = 1.0.
c For w/c -, 1.0. rheological p
determined by vertical capillary viscometer.
Ref. /
No. I
!
I
from
- .

pp -
-
S1
No.
I I I I r~ifferent cement co~npositions with varying 1 bob inside a cylindrical cup. 1
122 1
Author/ (s)
Fredriksson, A
Grzeszczyk,S.
Kucharska, Id.
Year
Objective of the study
-
properties of cement was investigated
W/C ratio, super plasticizer content and silica
fume content have been tested at different
frequencies, amplitudes and at difl'erent times
after mixture.
---
*To consolidate the earlier works on the effect
of vibration on rheological properties of fresh
cement pastes.
-To investigate rheological behaviour of
modified cement pastes.
-To determine the most significant ingrcdient of
cement paste, as well as their influence from a
rheological point of view.
-. - . -
-To review the large body of inforlllation on the
characteristics of fresh pastes, especially the
rheological properties of cement pastes.
{ml%o
- - - - - - --
Equipmentlmethod used
Ref.
-- - --- -
Brookfield viscometer ~lt11 a rotat~ng
-Two-pt. workability apparatiis.
-. - -- pp
investigate the influence / *l~eological
@Regressive modcis of paste are obta~riotl 111
the form of a six-fact01 eqttatlons
Relative influence of each factor (colnponent)
is c~itlcally ailnlysed
- -- -
-1:actoi-s involving mcawlement ploblcms and
conlments 011 the analysis of expel imerltal data
have been mnde
-Substantial gaps in the knowledge of ccmcnt
pastes, cspccially on rheological
measurements using rllcorneters, proceduscs
adoptcd in the lest. rheological (theoretical)
models, have been identified.
- - - --
bchav~our was detcnnined on thc
I I clinker phascs and introduced fro111 the outside ( basis of consistency curves and stress changes I
together with make-up water, on a constant shcar rate.
propertics of pastes in Portland cemcnt at an
early stage of hydration(

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aJ2
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D
S

I S1 I Author/ (s) 1 ~earm~ective
Maeder, U.
Gad, E.A.M.
-- -- -- - - -
-.
of the study
pastes and mortars.
*-- - ---
*To study the compatibility between SPs (four
--
1 %Giprnent/method used
*I'astes containing upto 40% of' slag \\as
considered along with Sl's 1i)r stucly~ng ~hc
various characterlstlcs.
-- ---- -- -- --- --
el;low table spread was measured after 30 and
/ types with cerner~t/flyash blends with three 60 minutes of additlon of'Sl's
I I different types of flyashes. I aviskonzat Nl' - a rotary paddle v~scometer-
Compatibility study was carried out by
measuring the fr-esh and hardened mortar
properties and flow bchaviour obtained Ii0111
flow table spread - - and - rheological - properties
- --
*So study the structr~ral effect of different
adlnixtures on the flowability of diSferent
cement types, based on rlleological parameters.
.Normal Portland cement, sulphate resisting
ccmcnt, high slag cenlcnt and flyash cement
(75% NPC +25% flyash ) were used along wlth
three types of SPs.
was used to obtain the flow curves. 11'
measuring, torque (N-mln) aid slicar rate (in
rpm) to obtain the rheological par:inletcrs iclrl
stress and (plast~c) viscosit
-Relative tlowabllity lo
cement pastes 111 c~il divided by 10 cnl,
dialmeter of- the cone of flow test) ncre
deter~nineti for all types of ccrnent pastes mith
SPs.
rIU~eological paranlctcrs li)r all cement pastes
deterrnirled by a rotating cylinclrical
visconletrcr (Rheotcst 2.1. made in Crcrmn~iy)
I 1 1 I 1 to undc~stand the action modc of each
I I I I 1 adrnixturc on the dispersion of cernent
based carbon fibres on tlie rheological anci
niechanical behaviour of HPFRC.
particles-- _ -.-- ------ -
eViscorneter- (Viskomat PC) with controlled
speed of rotation and measurement of
moment due to resistance of mix measured.
I I .Pastes and mortars were considered to / -Test para~neters were controlled and
1 I I 1 study influence of matrix components on the I recorded by the program 'Visko' on a PC.
- - - - -
-
Ref.
No.
1 2'1
. . . Contd.

-
5
;c:
u 3
'E 0
2 %
i
" Y
I-'
3 . 5 -
g 3
:5$ 0 .d
m 3 ;
.2 $ "
g
2 El
az 5
-53 a.
. -
O d Z
5073 o
0 b)"
2 2 'Z
3
h 0 5
hg,
3 8 2
GEc$
0 272
k o c
e aid

Year
- - - -- --
Objective of the study - T e n t /method used
--
-
.To develop a technique for measunug the HT/HP (hlgh
temperaturefhlgh pressure) rheology of 011-well cements
To predict fr~ct~onal pressure drop during cement
displacement - -- --
- - - -
obta~n rheological measurements \wth
two dlffcrent slze tubes, was also used
.A large-scale pipe-flow fac111ty was
co~lstructed to conduct euperlmcnts on 1
laminar-lurbulent translt~on of ccrue~lt
slurries at relatively low shear rdes
1
-, - - - :
@A ~ons~stonietcr was rilod~fied to IiJ
enable to~que and rotsuonul speed to hc I
recordetl. and used to obtaln ~Iieologlcal
propertics of slu~ rlcs .~t 11.1 /I II'
-. -
1
!
I

Table 2.7: Overview of Rheological Studies on Cement / Cement - Based Grouts
Palardy, D. and
Ballivy, G.
--
Year Objectives of the study
2000
*Cornpatability of different cements and HRWR s
and the influence of materials and mix proportio~ls
on grout properties, espccially the rheological
characteristics and setting time of micro-fine
cement- based grouts. -- --
Equipmentlmethod used
.Fluidity and setting time of different grout
mixtures studied
a Grout fluidity characterized by modifictl hlarah
cone flow test and mini-slump test.
- - -- -
I
i
Ref.
No. j
13.5 I
I
I
I

Table 2.8: Overview of Rheological Studies on Ccrne~it mot-tar
-- -- -- -
Sl. Author1 (s) Year Objectives of the study
~yui~ment / mcthod used
Ref.
No.
No.
- -- -- -- --.- 1. Nessim,A.A. 1965 -7'0 study rheology of cement mortar and compare its eRotational viscometer specially designed lot '15
Wajda,R.L.
behaviour with that of concrete under vibration
the study.
I
2 Kakuta,S. 1996 *To study rheological properties of mortar composed in oA Rrookefield (l3-type) viscomcter \\as
t, s
Kokado,T.
consolidation free flowing (CFF) concrete.
used to obtain the flow crirves of CI.1;
mortars. - -- - -
-To study the rheology of fresh cement mortar aid to *A visco-corder was i~\ed to study the 136
explore the naturc of - structural --- - breakdown in mortar rheology of mortar.
--- - - - -- --- -
eTo study tlic rheology of ftesh mortar and to decide oVisco-corder (a st~~illl variable speed 117
whether or not the v~sco-colder can glvc flow curvcs for consirtonletcr) wab i~sed to detcrininc tllc
mortar. -- rhcology oi' frcsli mortar
- -
-_ - -
-Design and cxperi~ncntal validation of a coaxial .Coaxial cylinder vi5coineter WLLS build
ITS
cylinder viscometer developed from the two-point cons~dering sa~nple \in>, gap si;.e, cylindtsr
workability apparatus.
radius ratio and ~url'rtcc profiliilg as dosign
I
I requircmcnts 1
/ ~Spccd and torque mere checked and t11c11 tllc I
I flow curve of a L

I S1. 1 Author1 (s) I Year ( Objectives of the study I Equipment I method used
*To study the feasibility of using a coaxial cylinder
viscometer for using to study the rheological parameters
of cement mortar.
.To review the rheological features of mortar and
selected features of the behaviour of the material.
*To assess the material properties and workability
characteristics of plastic mortars morc objectively, than
already available.
.Five types of plastic tnortars considered for evaluation.
o'I'wo-point workability apparatus for tcsting
concrete was moclified so as to be suitable fbr
testing mortars containing particles ilpto 2
mm in diameter.
.Results of rcsearch for the past 20 years
---
were used to highlight the developments.
--- -- -.-A ----- -
eConventiona1 workability test (flow table)
rcsults werc compared wit11 that of
rheological studies
~Rheo~neter available with K. Vogel
Research laboratory together with
RIiEOTEST - a rileometer available in
-
Ref.
No.
1 4 1
.-"";"i"-"";
Sundararaj an,T.
Gerniany were used. - - - .- -
*To experimentally investigate the influence of flyash evisco-corder M;~S used to obtain flow curves
on the rheology of fresh mortars (cement based) at four cylindrical speeds (0-240 rpm)
including mechanical properties with pitch-based carbon model used to obtairi yield value
fibres including small anlounts of SF. - vi5cosity in ternis of 'g'- and -- -'11'.
-- -
*To experimentally investigate the rlieological
properties of coir fibre reinforced cement mortar
ol'hree {nix proportioris ( 113; 1 :4 & 1 : S) and
four aspect ratios and fibre - contents
considered.
1 I *Flow valoc and cohesion -----.
.-- obtained --
- - .
I I

Table 2.9: Overview of Rheologicaf Studies on Concrete
S1. I Author1 (s) 1 Year I objectives of the study
-Development of an apparatus to measure the
flow curve of concretes of medium to high
1 workability. -.
2. 1 Wimpenny,D.E. 1 1987 1 -Modification to Tattersall's 2-pt workability
apparatus for concrete.
3. Wallevik, O.H.
Gjom,O.E.
-Modification to Tattersall's 2 pt workab~llty
apparatus for cotlcrctc, to overcome
segregation of concrete and in operation of
the equipment.
- -- --- -
-To develop a rheoinenter which can be used
both in the laborato~y and at the site for
concrete having - consistency
--
soft- to flu~d
- -- --
-Modification to Tattersall's 2- pt test
apparatus fol measuling \vorkabiI~ty of
concrete,
6. / Tattersal1,G.H. 1 1973 / The need to develop a two-pt workability,
7. Domonc,P.I..J. 1999
Xu Yongrno
Banfi11,P.F.Ci.
8. Ferraris,C.F. 2001
Obla,K.H.
.To develop an improved version of Tattersall
2-pt workability apparatus for thc study of
rheology of IIPC mixes.
oTo select the type and dosage of mineraladmixtures
that i~l~provc concrete workability.
--- -.-.
-- -- ---- -
---
Equipmentlmethod used
.- .- - --
eTwo point workability test setup tiebcloped by
Tattersall
-- - ---ppp-p
- -
ePressure gauge and pressure transdueel used in pl:lcc
oS oil pressure system 111 the 2-pt uorkability of'
rattcrsall Susccptibll~ty of concrete rnis to xegreg'ltron
is qualified by a segregation factor(\)
- --- --- -
eOrigit~al Tattersall's cqulprncnt ~nodrfied to inclutlc
Kcf. /
No. !
1.1-5 I
pressure transducer to measure torque and an electronic ) 1
speed registration system n~ounted 011 tl~c
lxtO
1.1.7
equipment.
I I
- - -- -- -- eTorsiona1 rheometer tor concrete c'illcd 13'1 - IiIiIlOM I 148 ]
was developed aStei ovcrcomin~ the drawhacks of 1 1
earlier 2 pt. worhabil~ty test selup
- --_- -
*A torque tra~~sducer was developed and fittcd to the
origlnal 2-pt test set-up of I attersall l'h~s arrangerncnt
is easier to operate and glving full rccord of what
happens during the teit - - - -- -
*Basis to 2-pt workability test and relating torque and
speed to intrins~c properties of concrete.
- - -- -
.'l'wo types of ~mpellers developed and 11- impeller
system foulltl to be s~u~abls for testing concrete.
Concrete rheological behaviour was tested using the
standard. slump cone test, which is a11 indication
... Contd.

. - -. - -
Year / Objectives of the study I Equipmcntlmethoci used
--
-
Hcf.
No.
-. .
--
+-
sl~ghtly (called tlie
frcsh concrete.
mocilfied slump test) to measurc both yicld stress and
1980 1 *To study the effect of concentration of super I e I'wo-pt. method of determlnlng - workab~llty.
plasticizing admixture upon workability -
--
1996 -To suggest a new rheological test method for eA coaxial-cylinder viscorllcter for concrcte was uicd to
consolidation-free flowing concrete (CFF measurc the flow curve of C1:l7 concrete.
concrete)
eA spiral flow twin shaft rnrxer was uscd and rcrnodclcd
I
with a vicw to obtarn the rotatlng speed and electric
I power of mortar and cornpare with rheology test of
coaxial-cy linder viscometer. --
1992 rTo connect the rheology of cement paste cA new parameter "gap" which is rclatcd to thc spacing
concrete rheology.
betwcen aggrcgatcs prescnt In concrete, In addition to
the two usual parameters considered.
---- - -
by cxpcrilnents the
v~sco~nctcr-vane type mpeller was uved for
between a ficld stress of fresh
which was debeloped by the author
structure
0 1 hree-phase structure of fresh concrete described bv
three parameters characterizing the structure of
aggregate, cement paste and concrete mix con~posed of'
. .~ . proposed .- ~-
1990 -To investigate the asscssmcnt of stability of workabiltty apparatus with a pressure
fresh concrete mixes.
transducer system attached and linked to a rnic1.o
esubjective assessments of' bleeding and
to rclnovc distortion arid reduce operator
cohesion on fresh concrete and ultrasonic inherent in the manual method of
1 pulse velocity - (VPC) . measurements on I measurement of flow curves.
hardened concrete are to be related to
in shapc of pressure traces might be used to
-.
in the Tattersall proneness of a mix to scgregatioil and
... Contd.

- - - - - -- - - -- - . - -
S1. Author1 (s) Year Objectives of the study
No.
- .- - - -- - - - -- -
workability apparatus. bleeding. - - - - - - -
15. 'attersall,G H. 1990 -TO study the effect of vibrat~on on apparatus was uscd
I I 1 curves of concrctcs and sur~~rnarizc the 1 I I
'
Kojima,T.
I botlo~n
-1
-
(in terms
of flow curves) of concrete under vibration.
- - - --
-I

S1.
No.
Author/ (s)
Gjorv, O.E.
Objectives of the study
viscosity.
-- .-
Equipment/method used I Ref. I
----- --- - - --- -- - --
oIJslng non lincar regression analy51s a nlethod Ibl
dctcrminlng two Bingharn constants arc p~oposed
'Theory was generalized and a inodel for prediction of 1
Tattersall, G.H.
Baker,P.H.
-'Yo dctennine the fluidity of fresh concrete
while being vibrated.
.To study the effect of vibration on the
rheological properties of fresh cotlcrcte .
-'To understand the applicability of Bingham
model (linear) for concrete under vibration. -
-'To obtain the relationship, if any, between
the British standard tests for workability and
the two-pt test
-To obtain a simple theoretical equation for
rl~eological behaviour of concrete.
-To predict the dependence of flow properties
of concrete upon aggregate volume
concentration, both for the case of (i) cement
paste-assumed to be a Newtonian fluid and
(ii) cerne~lt paste assumed to be a Bingharn
-- -
viscosity of - HPCs ,proposed.- -- -
eA vertical pipe apparatus is ~~sed to allow the flow of
concrete under vibration, as the rate of flow 1s assumed
to be proportional to thc hydrostatic .-
head.
.The bowl of a two-point workability test
~nou~ltcd on an electromagnetic vibrating ~ablc for
measurements on unvibratcd concrete and
---AT
on concrete
under vibration. --- -.
el he results oblalned by Scullion [The measurement of
the workability of fresh concrete, I'hesis submitted to
the IJnivof Shefiield Tor the Dcgrce of MA,
1975,pp.182] on the Hrit~sh test for workab~lity (slump and
conlpacting factor and vcbc test) wcrc compared with 410
the results of two-point test
the equation relating rcsults from the thrce British
std.tests. as obtained above, was also tested extensive
data published by other workers[Singh,B.G; Dewar 1
J.D.Hughcs, - -- J.D., and Ri tchie, A.G.B.
-I-
- -
.Viscocity -clast~clty analogy was uscd to obtain 170
equations for flow behav~our of concrete
~Predicated values cornparcd with experimental results
of other iilvestigators on rheological properties of
concrete
... Contd.

~
I - No.
Author1 (s) I ~ e a 1 Objectives r of the study
Ritchie, A.G.B.
- --
- ---
fluid.
1971 -To discuss the results of shear strengths
measurements obtained during an
investigation illto some fundamental
engineering properties of plastic concrete, in
which, particular emphasis was placed upon
the analogous behaviour of soils and
plastic concrete.
-. -
1962
-
2003 _
- - -- -. - --- - - - - - -- - - -. -
~- - - - - -- ~
-Shear strength parameters of plastic concrete werc
studied with particular reference to the effect of w/c
ratio.
~lJndrained-u11co11soiidatcd and consolidated-undrained
triaxial tests were performed.
Pore water pressures mcasured and shear strength
parameters (apparent colicsion and angle of shearing
resistance ) have been determined in terms of both total
and ------p-p---
effective stresses. - -
-Developrnellt of a test to assist in the eDirect nlcasurclncnt of thc angle of internal friction of'
expression of mobility in fuilda~l~ental fresh concrete and to express it in f~~ndamental tcrms, by
physical units.
a triaxial tcst (3-D stress systenl was carriedout.
-To divide the workability of a stable .Results co~npared with slump, V-R time for low,
concrete rnix into properties of medium, high workability ranges.
'compactability' and 'mobility'.
Apparent
-
cohesion and angle of internal friction were
measurcd fro111 ---
the -- triaxial test.
~
'Excess paste' as porl3oscd by Kennedy,C.T., was
---
-Development of a new typc of rheometcr to
measure the rheological properties of self
compacting concrete (SCC)
1'0 dcvelop a new mix design method for
SCC.
- - .-
-Compare -- the -- five rhcometers data using a
-
used and considering concrete as a two-phase flow to
investigate how rheology affects the behaviour of the
aggregates.
.Flow cone as specified in J1S RS201 was used to
measure tile flow values of paste.
Slump tcsts conducted by AS'TM C 143-78 standard on
cotlcretes
.Flow and rheology properties wcrc also obtained from
a specially designed cylindrical rl~eometer. --
-Data frorn all instruments could be dircctly and
--
--
No. _
-- ~
-.
171
169
172
--~ - ~- -
173

Author1 (s)
objectives of the study
-
Ref.
No.
-- -- -- to interpretation of results etc.
*33 testing methods are plcscnted, out of wh~ch 5 dcal
wlth rheology of concrete.
Only 3 comlnercial - type rheometer based tests
presented. - -- --

2.5 STUDIES ON NATIJR4L FIBRE COMPOSITES
In this section, reported studies on the wet characteristics, strength and durability
characteristics of the composites (cement .:' cernentitious), studies on the various products
based on natural fibre composites and miscellaneous studies (covering transition zone
characteristics, shrinkage characteristics , including reported reviews) are presented.
2.5.1 Setting Characteristics
Bilba and others [lSO] studied the influence of the (water extractives, hemi-cellulose,
cellulose and lignin) botanical components on the setting properties of bagasse 1 cement
composites. Different compositions of cement, bagasse fibre, with water were chemically i
thermally treated (175-250 OC) and the time to reach the highest temperature of hydration,
highest temperature of hydration (OC) were noted. The influence of (1) botanical
components of the fibre, (2) thermal 1 chemical treatment of the fibre, (3) bagasse fibre
content and (4) added water percentage were investigated. It has been concluded that
(i) there is a retarding effect of lignin on the setting of cement composite, (ii) for small
amount of heat-treated bagasse (200 'C), the behaviour of the composite is closely the
same as that of classical cement or cellulose /cement composite.
2.5.2 Rheological / Workability Characteristics
Ramakrishna and Sundararajan [I811 carriedout experimental investigations on the
rheological properties of a superplasticized coir fibre reinforced cement mortar, such as,
flow value, cohesion and angle of internal friction, by the flow table test (for flow value)
and by 'direct shear test' (for c and 9) for coir fibre reinforced cement mortar (15; fibre
content = 1.5%, with respect to wt, of cement; aspect ratio = 70). It is concluded that
(i) it is possible to identify the limits of W/C ratio of the composite to match the
workability of reference mix, by adding the superplasticizer; (ii) the dosage of the SP can
be fixed by the rheological study to achieve the flow and cohesion of the reference mix.
2.5.3 Strength Characteristics
Ramakrishna and Sundararajan [I821 investigated the impact strength of coir, sisal, jute
and hibiscus Cannebinus reinforced cement mortar slabs (1:3), under a simple projectile
impact Ioading, with four different fibre contents (0.5%' 1.0% and 2.5% - by wt. of

cement) and three fibre lengths (20,30 and 40 mm). The relative performance of the above
composites were evaluated based on the set of chosen indicators, namely, impact
resistance (R,), residual impact ratio (I,,), impact crack-resistance ratio (C,) and condition
of fibres at ultimate failure. It is concluded that the addition of above natural fibres in
cement mortar slabs have increased the impact-resistance by 3-18 times than that of plain
mortar slab and that coir fibre reinforced mortar slab specimens showed the best
performance.
Kriker and other [I831 experimentally investigated four types of date palm (phoenix
dactylgern) surface fibres for their mechanical and physical properties and also the
strength, continuity index, toughness and microstructure of date palm fibre - reinforced
concrete. The influence of volume fraction (2-3%); length of fibres (15-60 mm) curing
regimes (water and hot dry curing with varying temperatures RH) on compressive, flexural
strengths and toughness coefficients were investigated. It was concluded that (i) date palm
fibres available in Afro-Asiatic dry band can be utilized in local construction materials;
(ii) compressive and flexural strength properties of concretes cured outdoors was found to
be lower than for those conserved in water curing.
Savastano Jr., and others [I841 used BFS - activated either by OPC or gypsum and lime
combinations as a binder for cellulose - cement composites prepared by a slurry vacuum
de-watering.method and using pinus radiata and sisal kraft pulps as reinforcement, with a
view to preparing panel products suitable for housing construction. Modulus of rupture
(MOR), fracture toughness and modules of elasticity (MOE) were evaluated for various
binder formulations. It was found that the slag chemically activated by mixtures of
gypsum and hydrated lime generally displayed optimum strength and fracture toughness
properties and that a formulation of BFS activated by 10% gypsum and 2% lime presented
a good compromise between strength and energy absorption combined with a reasonable
price.
Savastano, Jr., and others [185] used sisal and banana strand fibre residue and eucalyptus
grandis kraft pulp - mill waste from Brazilian sources as reinforcement in OPC and were
subjected to various preparatory processes, in cement-based composites. The study
adapted conventional chemical pulping conditions for the non-wood strands and a sluny
vacuum de-watering method for composite preparations followed by air-curing. Flexural
properties of the composites and that of the reference materials (plain cement paste and
pinus radiate kraft reinforced cement composites) was found. The optimum performance

of the composites was obtained at a fibre content of about 12% (by wt.) and that E grandis
was found to be the preferred reinforcement for low-cost fibre-cement, among the fibres
studied.
Savastano Jr., and others [I861 evaluated the performance of fibres obtained from
commercial and by-product sisal (Agave sisalana) by thermo-mechanical pulping and
Chemi-Thermo-Mechanical pulping (CTMP) processes and using them as reinforcement
in binders, namely OPC and chemically activated BFS. Cement composites with 4-12%
(by wt.) were prepared by vacuum de-watering technique, MOR, MOE and fracture
toughness (FT) of the above composites were determined by three-point bending test.
SEM studies on the interfacial bond were carried out and related to the mechanical
performance of the above fibre-reinforced pastes. It was found that (i) at 8% fibre-content
the flexural strengths were similar between the composites considered and (ii) there is allround
improvement in above properties, water absorption and density values.
Siddique [187] carried out experimental investigations to determine the physical and
mechanical properties of natural san (Crotolaria Juncea) fibre and its effect on
compressive strength, splitting tensile strength and flexural strength (MOR) of concrete,
using 0.25% to 0.75% of fibres and 20 - 30 mrn lengths. Experimental values of the
mechanical properties of san fibre reinforced concrete have been compared with the
theoretical model developed by Pakotiprapha and others (for steel fibre reinforced
concrete and based on law of mixtures). It is found that good agreement exists between
theoretical and experimental results.
Jorillo Jr., and others [I881 extensively studied the compressive stress-strain properties of
concrete and mortar matrix reinforced with coir fibres to investigate the inter-relationship
of fibre reinforcing parameters, such as, fibre volume fraction, length or aspect ratio, in
combination with different grades of concrete or mortar matrices (WIC = 0.4 - 0.6; AJC
= 0.8 to 2.6; SIC = 1.0 to 3.0; Lf= 15-50mrn; Vf= 0-3.0%) and the resulting stress-strain
properties of the fibre-cement composite material in compression were evaluated. To
characterize the stress-strain curve of a fibre concrete / mortar, a fractional second degree
polynomial model developed by Sargin and modified by Wang et.al was used. It has been
concluded that (i) the presence of coir fibres altered the morphology of failure during
compression, ie., gradual failure occurred inspite of the presence of propagating vertical
cracks which ultimately maintained the structural integrity of the material (ii) addition of
coir fibres at low-volume fraction (Vf < 2.0%) to cement mortarlconcrete didn't alter the

compressive strength significantly and MOR of composite. However, inclusion of fibre
volume in excess of 2% may result in significant decrease both in strength and elastic
modules due to mixing difficulties; (iii) enhanced ductility and energy absorption
capability of the composite, in terms of significant improvement in peak strain, inflexion
stress and strain residual load, were observed; (iv) linear relationship derived between
fibre-matrix parameters and stress-strain relationship can sufficiently predict the properties
of natural fibre composite; (v) analytic expression proposed by Sargin can generate the
entire stress-stain curve of coir fibre cement mortar or concrete.
This model can
effectively estimate the stress-strain properties of a fibre material based on the knowledge
of compressive strength of matrix or plain mortarlconcrete (o,,) and fibre parameters such
as Lf, Vfand Ef.
Okafor and others [I891 prepared thirty-six CM mixes (SIC = 1 to 6) of widely differing
WIC ratios (0.4 - 0.9) were used to prepare fibre - mortar mixes with fibre volume
fraction ranging from 0.5 to 4.0% Compressive, tensile, flexural strengths of the
composite were determined in order to study the effect of mix proportions on these
properties and compared with plain mortar mixes. The results showed that (i) palmnut
fibre reduced the compressive and tensile strengths of mortar, (ii) the flexural strength of
the composite is improved upto 33%; (iii) SIC ratio of 2.0, W/C= 0.60, and Vf = 2.0%,
were found to be the optimum mix proportions.
Coutts and Warden [I901 studied the mechanical and physical properties of fibre cements
by incorporating sisal pulps (prepared by kraft and soda processes) with a view to use
them as building products. Fibre cement pads with fibre contents ranging from 0.5% -
12% (by wt.) were prepared for mechanical testing at 28 days (three-point bending test to
evaluate MOR, MOE / flexural modulus and fracture toughness). It has been concluded
that (i) superior products suitable as building materials can be fabricated using sisal pulps
(with optimum content = 8% - by wt.) and (ii) there is a 50-60 fold increase in fracture
toughness over neat matrix and (iii) the flexural strength is about double that of the
matrix.
Islam and Alam [I 911 investigated the effect of incorporating various percentages (0.1-
0.9% by wt.) and lengths of (0.25- 1.0 inch) of different types of chopped sisal and coir
fibres in concrete. It has been concluded that addition of fibres has decreased the strengths
(compressive & tensile strength) in concrete and that jute fibres perform better than coir
fibres.

Singh [I921 presented the results of three - point bend test on un-notched and notched
randomly oriented coir fibre reinforced concrete beams, using W/C = 0.55 and Vf = 3%
(by wt.). The beams were tested under cyclic loading and load-deflection curves for
various load cycles have been obtained. It has been found that (i) coir reinforcement in
conjunction with load - cycling enhances usehl life of concrete; (iii) computed initial
crack toughness show that the scatter in the fracture toughness value is within 1.5 percent.
Ziraba and others [I931 used sisal fibres with an aim to establish the fracture
characteristics of sisal fibre reinforced concrete using a model similar to the one proposed
by Visalvanich and Naaman [194] for the fracture characterization of steel fibre reinforced
concrete. A theoretical fracture model equation, requiring as input experimental data
obtained from tests on notched specimens, was developed to predict the crack resistance
curve for sisal fibre concrete, which can predict the steady state fracture energy (G,), using
as input parameters Vf, Lf and Of. The theoretical model was validated from experimental
data from fracture tests using double cantilever beam specimens. It was found that
(i) close correlation is seen between the fraction energy curve as obtained from test
measurements and the proposed theoretical model; (ii) the concept of critical crack
opening angle (CCOA) as a fracture criterion is applicable to sisal fibre reinforced
concrete and it is found to be a function of the fibre reinforcing parameter, VfLf /Qlf
Guimarges [I951 showed the use of sisal, coir, piassive (Attaleafunifera), bamboo, sugarcane
bagasse, in cement composites. The influences of some parameters - Lf, Vf, matrix
proportioning, casting processes, on the properties of composites, such as, flexural
strength, water absorption and specific gravity were studied. Dwelling components like
roof tiles, kitchen sinks, water tanks by simplified processes were given. Advantages of
fibre reinforcements and reinforcement in mortars have been highlighted, with the need to
evaluate and ensure durability of fibres / composites.
Aziz and others [I961 have presented the results of investigations conducted on the
strength properties, physical performance and durability aspects of cement-based
composites reinforced with coconut and jute fibres.
Siddique [197] studied the effect of replacement of cement by flyash (40-50%, by wt.) and
the subsequent effect of addition of natural san and steel fibres (0.25- 0.75%) on the
compressive stress-strain behaviour of concrete. Modulus of elasticity of high fly ash
concrete and fibre reinforced high fly ash concrete were obtained from the above curve.

The results indicated that (i) repiacement of cement with fly ash content increases the
compressive strain of concrete and reduces its modulus of elasticity; (ii) incorporation of
both types of fibres enhances the ductility of high fly ash concrete, but, does not
significantly affect the modulus of elasticity of high fly ash concrete.
Siddique [I981 examined the effects of addition of natural san fibres (0.25 -1.50%;
15 - 35mm - six different lengths) on the compressive strength of concrete. Based on the
experimental results obtained it has been concluded that (i) compressive strength of
concrete is not affected upto the fibre content = 0.75%, beyond which there is a sharp
decrease; (ii) maximum decrease in compressive strength occurs when Vf = 1.5% and
Lf = 35mm; (iii) third-degree polynomial gives better results
compressive strength, for specified fibre lengths.
for predicating the
Siddique and Choudary [I991 investigated the effect of jute twines on the flexural
behaviour of concrete beams with 1 without fibres. Jute twines (0.56%, 0.94%, 1.12% and
1.88%) of cross sectional area of the beam with fibres (25mm length; 0.75% - by volume
of concrete) or without fibres were used in the flexural specimen of beams, which were
tested under two-point load in flexure. Flexural strength and central deflection were
recorded. The results show that (i) jute improves the ductility of concrete; (ii) flexural
strength of beams has increased by 100% (with jute twines) and 121% (with jute fibres);
(iii) the first crack strength and ultimate load strength has increased with the addition of
fibres and twines; (iv) both jute twines and fibres have contributed to the increase in the
load - carrying capacity.
Siddique [200] studied the effects of incorporation of san fibre on workability (CF &
slump), compressive strength, split tensile strength of concrete. Six different volume
fractions of fibres (0.25-1.50%) and five lengths (15-35mm) were considered. It is stated
that (i) workability concrete decreases as the fibre content increases, for all lengths;
(ii) compressive strength - of concrete is not significantly by affected upto 0.75%, beyond
which significant reduction is observed, (iii) split-tensile strength increases upto 0.75%
and Lf = 25 mm, beyond which, there is reduction in strength upto 1.5% and that the
maximum reduction is observed for Vf = 1.5% and Lf= 35 rnm.
Siddique [201] evaluated the mechanical properties (compressive, split - tensile, flexural
strengths) of san fibre reinforced concrete (Vf = 0.25% - 0.75%; Lf = 20 - 35mm)
experimentally and compared with the theoretical values obtained using the model

proposed by Pakotiprapha et.al , which was originally developed for steel fibre reinforced
concrete. It has been found that the experimental results obtained with Vr = 0.75% are in
good agreement with those of the theoretical model proposed.
Kankam [202] investigated the possibility of incorporating palm kernel fibres in concrete
to retard the development of cracks. 100 x 100 x 600mm prisms containing 0.1% - 1 .O% of
palm kernel firbes were tested in uniaxial tension applied to the protruding ends of
centrally embedded bars. It is found that the inclusion of palm fibres in concrete increased
the stress in the reinforcing steel bar, corresponding to the developnlent of maximum
allowable crack-width in concrete at a fibre content of 0.8%.
Siddique [203] investigated the flexural behaviour of reinforced concrete beams (under -
reinforced i over- reinforced) with san fibres (Lf = 25mm; Vf = 0.25 - 0.75, by vol. of
concrete). Cracking strength, ultimate load, deflection, strain of concrete, crack - width
and their spacing were noted. It is found that addition of san fibres reinforced concrete
beams enhances the ductility, load - carrying capacity and curvature with an increase in
Vf and that the average crack - spacing and crack -width are reduced.
Morrissey and others [204] studied the bond strength of sisal silvers (strands of fibres
derived from Agave species) embedded in cement and protruding from one end of the
cement matrix. Tension test was conducted and modes of failure observed. It is found that
the critical length is equal to 30 mm, corresponding to an aspect ratio of 110 rt 50, which
is comparable with the aspect ratio of Pinus radiate fibres.
Mansur and Aziz [205] investigated the mechanical properties of cement paste and mortar
reinforced with jute fibres (Lf = 12 - 38mm; Vf = 1- 4%). Tensile strength, flexural
strength and toughness, compressive strength, impact strength, modulus of elasticity were
determined for 1 :1 and 1 :2 paste 1 mortar composites. It has been concluded that
substantial increase in tensile, flexural and impact strengths could be achieved by the
inclusion of short jute fibres in cement -based matrices.
Flexural strength and fracture properties of commercially produced wood - fibre
reinforced cements were studied by Mindness and Bentur [206]. It has been concluded that
LEFM is not a valid approach to explain the behaviour of 'wfrc'.
Rarnaswamy and others (2071 examined the suitability of short discrete vegetable fibres,
namely, jute, coir and bamboo for incorporation of cement concrete. A new approach of
mix proportioning based on 'optimum sand content', wherein particle interference and

specific surface effects of aggregates were optimized. Engineering properties such as
compressive strength, split tensile strength, MOR and impact toughness of fibre concrete
were obtained and compared with plain concrete (mix proportion : I: 3.58: 2.87 - C:S:CA,
WIC = 0.65, by W.). It has been concluded that (i) workable and homogeneous mixes can
be obtained using a special method of proportioning; (ii) while the strengths have shown
no improvement, deformation behaviour has shoun improvement in ductility and reduced
shrinkage; (ii) impact and fracture toughness of vegetable fibre concerts are also distinctly
higher.
Hess and Buttice [208] evaluated the behaviour of megass fibre (the result of the first part
of the process for extracting sugar i.e, the husk from Sacharus - OfJici~zarum) in cement
mortar in flexure, compression and tension. It is seen that total breakage does not occur
after first cracking and that the addition of sodium silicate (to inhibit delay in setting due
to the presence of sugar - a natural retarder ) has improved remarkably the strength of
reinforced mortar, in flexure as well as in compression.
Hussin and Zakaria [209] studied extensively the flexural behaviour of thin cement sheets
using coconut fibres as reinforcement (in flat / corrugated forms) at six fibre contents ( 1-
6%, by wt. ) and at two curing regimes (control and natural weathering of Malaysia for
periods ranging between 3 - 12 months ). Three - point loading was used and load -
deflection curves, cracking performance, water absorption, water tightness and bulk
density were studied. It has been concluded that randomly distributed fibres with different
aspect ratios improved flexural strength, cracking performance and ductility of both flat
plates and corrugated sheets ; (ii) flexural strength increased with increase in fibre content,
with the best perfonnance at 4% of fibre content and at WIC = 0.35; (iii) load - deflection
and strength characteristics have been affected by exposure to Malaysian weather, which
could be improved by replacing OPC by pozzolanic materials ; (iv) corrugated sheets
possess inherently higher strength than flat sheets, having potential applications in
building construction.
Filho [2 101 experimentally investigated cement mortar reinforced with sisal fibres under
flexure. Three fibre lengths ( 1.8, 3.7 and 5.6cm) were tested in different composites (eight
combinations of proposrtions) for their flexural strength (at 7,28 and 63 days) and impact
strengths. It has been found that (i) flexural strength decreases in the composite when
compared to brittle matrix; (ii) the composite shows an elastic - plastic behaviour after
multiple cracking; (iii) significant impact strength is noticed in all cases.

Savastano Jr. [2111 determined the consistence of mortar mixes reinforced with coir fibres
and compressive strength, flexural - tensile and impact strengths at the ages of 28 and 90
days Three different WlC ratios (0.65, 0.75, and 0.85) and fibres in their dry and in
saturated conditions were used in the mortar composites. It is found that the impact
strength of the composite has increased by 220 % and that of the tensile (flexural) strength
upto 175%. However, the compressive strength of the composite is found to reduce.
Chatvera and Ninlityongskul [I21 investigated the mechanical properties of sisal fibre -
modar composites containing RHA. The optimum fibre - cement ratio and unit weight of
the composite were used to determine the optinlum mix proportion, based on the
properties under compression. flexure and post - cracking behaviour of each mix. W/C
and .WC were kept constant at 0.7 and 2.0 and 30% RHA (by wt.) was used. It has been
concluded that (i) the MOE of sisal fibre -mortar composite, which is a function of
compressive strength, can be predicted by the 'rule of mixture'; (ii) the presence of air
voids has a remarkable influence on the strength of the composite and that the strength
reduction factor is found ot be 0.5 for flexural strength and 0.1 for MOE of the composite;
(iii) the optimum sisal fibre - cement ratio of sisai fibre - mortar composite (1 cm) is 0.16
(by wt.) and unit wt = 2150 kg /m3, based on the highest strength both in compression and
bending. (iv) sisal fibre boards are more ductile than mortar boards ; (v) modulus of
resilience of sisal fibre composite is higher than that of mortar board, especially at
optimum sisal fibre -cement ratio, unit weight and fibre length . Moreover its toughness is
considerably higher. Therefore, sisal fibre -mortar composites are remarkably more
ductile than mortar board; (vi) sisal fibre - mortar composites can be used in ceilings,
walls and form work and be given a thin layer of cement mortar when they are exposed
directly to moisture.
Shimizu and Jorillo Jr. [213] studied the microstructure and the basic mechanical
properties of both the reinforcing coir fibre and the fibre - cement composite. Tensile
properties (fracture strength, elongation and MOE) of the reinforcing fibre; effect of fibre
reinforcing parameters (Vf- 0.8 to 4.0%; Lf - 3 - 9 cm or Lld = 100 to 300) on the
properties of the composite in compression, flexure (four - point test) were investigated
for two mortar mixes (1:1:0.4 and 1:1:0.7) and for two methods of fabrication (random
and short fibres; hand - laying for long and continuous fibres). The effect of matrix quality
on the compressive property of the composite (at constant Lf - 3cm; Vf = 1 and 3% at
various proportions with WIC = 0.4 (0.1) 0.7 at a constant flow value of 180 mm) were

also investigated. It has been concluded that (i) micro - structural studies can provide
might into the behaviour of fibre - cement composite system up to the engineering level;
(ii) observed properties in compression like peak strains, toughness and ductility showed
significant improvement due to addition of coir fibres; (iii) the regression (linear)
relationships correlating secant modulus (E,) to the matrix compressive strength, fibre
volume and approximate aspect ratio, can be used as a first approximation of the basic
compressive properties of the composite and that they can be used in the analytic
generation of the stress - strain diagram.
Jorillo Jr. and Shimizu [214] studied the fresh and mechanical properties of coir fibre
concrete reinforced with short randomly oriented fibres. Three types of cement matrices
and the combined effect of fibre parameters on workability, compressive strength, flexural
strength, and tensile stress - strain behaviour were investigated. It is found that in spite of
only a nominal increase in flexural, tensile and compressive strengths , a significant
improvement in toughness, ductility and post - crack strength of the composite occurred.
It is also found that (i) workability in terms of mixture stability and mobility was greatly
affected by increasing fibre volume and aspect ratio; (ii) mechanical properties
(compression, flexure and tension) correlated with major parameters (secant modulus of
elasticity - E,, Vf, L/d, plain matrix flexural strength ) in the form of simple empirical
expressions in the form of composite - mechanics approach, which can be used as a first
approximation of basic properties for design; (iii) the reinforcing index [ Vf (Lld)] has the
most significant effect in flexure and tension and manifested in the form enhancement of
peak strain (10- 20%) in proportion to the above index; (iv) significance of aspect ratio is
evident in workability and properties of compression; Lf in MOE and ultimate
compressive strength; overall surface area in spanning the crack at post - peak stages,
resulting mode of failure and post - cracking load capacity; (v) significant improvement
in toughness in compression and flexure; (vi) behaviour of coir fibre concrete modes
freeze - thaw is similar to that of reference (air -entrained) concrete.
Ramirez - Coretti [215] investigated the physico - mechanical properties of fibre - cement
elements made of rice straw, sugar cane bagasse, banana racquis and coconut husk fibres.
Cut fibres were treated with NaOH (2%) for 48 hours to remove part of lignin, rendering
fibres less stiff and easier to mix. Three different fibre percentages (1 - 3%) constant WIG
= 0.35 were considered and various physical properties (unit wt., volumetric variation,
water absorption, mechanical properties (MOR, MOE) were investigated. Strength

properties were evaluated at 28 days and on paired samples afier a six - year period of
exposure to natural indoor ambient conditions. Morphological properties of the source
fibres were conducted following microscopy procedure. It has been concluded that
(i) fibres and fibre - cement specimens considered show differences among them in
morphological and physical properties; (ii) no significant differences in strength relative to
the un-reinforced specimens are observed, yet fibre - cement specimens are found to be
more ductile; (iii) physical properties vary according to fibre percentage; (iv) fibre
percentage over 3% show difficulty in mixing and placement.
A research study on the properties of fibre reinforced concrete, using among other fibres,
coir (Lf= 25 - 30mm ; Vf = 1 - 3%, by wt. ) and adopting mix proportioning approach of
ACI on absolute volume basis have been carriedout at Maharastra Engineering Research
Institute, [2161, Nasik, India. Compressive strength, split tensile strength and flexural
strength (at 7, 28 and 90 days), static modulus of elasticity and abrasion resistance
(at 28 days) were determined. It has been found that (i) workability of concrete has
reduced and that the slump of concrete with coir fibres decreased abruptly, which may be
due to interaction between fibres and the matrix of the concrete including water absorption
capacity of coir fibres; (ii) best tensile strength is attained at 2% (by uT.) and that the
increase is about 15 - 20% over unreinforced concrete; (iii) flexural strength of coir fibre
concrete is maximum at 1.5% and that the increase in the strength is about 15 - 25% over
reference concrete; (iv) there is little or no significant on the compressive strength of the
material regardless of percentage of reinforcement; (v) increase in elastic modulus proves
its suitability got their structural components ; (vi) there is improvement in resistance to
wear; (v) it is not desirable to use Vf> 3.0%, as it would cause problems in mixing,
handling and quality control.
Properties of fibre reinforced concrete using plant fibres were investigated at Andhra
Pradesh Engineering Research Laboratory, Hyderabad, India, using palmyrah and coconut
fibres. [216] Dimensional stability, stress - strain behaviour (dry, soaked in water and
alkaline solution), mechanical strength behaviour (compressive, split - tensile, flexural and
impact strengths) and shrinkage and permeability characteristics were evaluated for both
types of concretes. It has been concluded that (i) there is no improvement in compressive
strength of the concrete and that compressive strength reduced with higher percentage of
fibres; (ii) split - tensile strength and flexural strength showed maximum strength at
Vf = 1.0% for both types of fibre reinforced concretes and that the strengths were higher

(23% & ! 5%) over plain (reference) concrete; (iii) impact strength increased by 1.9% and
I 7 times over reference concrete at V, = 3%, (iv) balling is significant for over 3% of
fibre content (lld = 90); (\I) shrinkage is reduced to about 50% with 3% of fibre;
(vi) permeability is negligible; (vii) fibres are found to be durable in the alkaline
environment of concrete matrix, even after 3 years.
Krishnamoorthy [217] has presented the results of the experimental investigations on the
strength and deformational behaviour of vegetable fibre reinforced concrete carriedout at
1.I.T Delhi. Jute, coir, bamboo fibres were used and the optimum fine aggregate content of
concrete mix for reducing the effect of particle interference when fibres were added, were
examined. The results show that (i) coir fibres (at 2% by wt.) did not affect the
compressive strength adversely, but, fibre additions enhanced crack - arresting and impact
(toughness) properties significantly; (ii) the other fibres employed (bamboo, jute) are not
promising in terms of maintaining compressive strength, but, otherwise, performed well.
Ramakrishna and others [218] have presented a comparison of theoretical and
experimental investigations on the compressive strength and elastic modulus of coir and
sisal fibre reinforced concretes for various fibre - volume contents (0.3: 0.5, 0.7 and 15 -
by vol.). Law of mixtures was used for the theoretical computation of the elastic modulus
of the fibre concretes. It is observed that the theoretical and experimental values of elastic
modulus differ by acceptable levels and that the maximum compressive strengths are
obtained at Vf = 0.5%, by both methods.
Buch and Hiller [219] compared the mechanical, durability and consistency properties of
two high strength concrete mixtures (strength 40 - 60 MPa) with / without polypropylene
and cellulose fibres and compared with reference concrete. Conlpressive strength, flexural
strength, impact properties, fracture toughness, stress intensity factors and elastic moduli
properties as a function of time and curing regimes were evaluated. It has been concluded
that (i) the above fibres provide a balance between mechanical, physical and durability
characteristics when placed in a cement matrix; (ii) improved reinforcing properties of
fibres can be attributed to the suppression and stabilization characteristics of the fibres;
(iii) high fibre count, large surface area and high elastic modulus are ideal for
reinforcement efficiency; (iv) the above fibres have a potential to improve compressive
and flexural strength of concrete mixtures, both nornial strength and high strength,
concrete mixtures with fibres have improved impact and toughness properties ; (v) the

nfrastructure industry can benefit from the beneficial properties of these processed
cellulose fibres.
England and Toledo Filho [220] have comprehensively reviewed and presented the
performance of mortar reinforced with sisal fibres, based on their influence on the
development of plastic shrinkage in the pre-hardened state, on tensile, compressive and
bend~ng strength in the hardened state, and on the long-term deformations (creep,
shr~nkage). The results of flexural strength indicate that (i) the increase in flexural
toughness is related to fibre content and fibre length upto approximately 50 mm;
(11) problems caused by time -dependant mineralization within cell structure and a
reduction of toughness and strength can be partially overcome by subjecting thin sections
to carbonation treatment and by pre-treating the fibres with silica- fume slurry;
(iv) workability is reduced by the addition of fibres and for Vf >3.0% , and changes in mix
proportion necessary to achieve compaction; (v) both plastic shrinkage and early - age
shrinkage are reduced significantly by the inclusion of sisal fibres even at low fibre
content ( = 0.2%); (vi) compressive strength reduces by about 30%, for 3% fibres
whereas, there is substantial increase in toughness; (vii) fibre pull-out will generally
precede tensile facture, if Lf ,SO mm; (viii) there is need for a better understanding and
definition of toughness for fibre reinforced composites, due to the way toughness indices
are computed based on different codes; (ix) crack healing can occur more readily in sisal
fibre composites, than other fibres.
Fordos and Tram [221] studied the use of cellulose fibres as reinforcement in cement -
based matrixes. Physical, chemical, mechanical properties of cellulose fibres, effect of
cellulose fibres on the strength (wet and dry) of fibre -reinforced products and production
process were studied. Air - cured and autoclaved cement pastes and mortars, reinforced
with wood - pulp fibres have been tested in bending (wet and dry conditions) and the
fractured surface examined by SEM. It has concluded that (i) it is possible to produce
cellulose - cement sheets as substitute for a variety of AC sheets (such as buildings boards
, cladding panels etc.); (ii) cellulose fibres incorporated into cement matrix retain strength
even after 4years; (iii) tensile strength and MOE of cellulose cement decrease when the
fibres are wet; (iv) the developed sheets attain strength similar to that AC sheets; but
sensitivity to wetting that AC; (v) reduction in bending strength of 40% is observed, when
the sheets are exposed to wet conditions; (vi) there is increase in impact strength;

(vii) there is need for further research to enhance the wet strength of ceilulose- cement -
based products.
Nagaraja [222] investigated the strength and behaviour of concrete elements reinforced
with bamboo fibres and strips. Split - tensile (on 150mm cubes) and MOR on beam
specimens reinforced with bamboo fibres ( 1 x lmm square section; 50mm long, 1- 4% by
volume) were determined and compared with plain concrete strengths (MIS). It is found
that there is significant increase in the tensile strength of the composite, the increase being
nearly linear with increase in fibre content. The optimum fibre content is found to be 3%,
based on the gain in strength of the composite.
Khazanchi and others [223] investigated the structure and properties of sun hemp fibres
and developed cement composites for roofing and walling components. Resin or calcium
silicate coatings were given to the fibres, before incorporating them in the composite, to
make them fungal and moisture proof. Load carrying - capacity of sun hemp - cement
sheets
(1.25 x lm) were measured for a span of 1.0 m. Moisture absorption and bonding
between fibre and cement was also observed. It is seen that adequate strength of the sheet
could be obtained and hence can replace conventional AC sheet, as a roofing material.
Khan and others [224] have investigated the effects of sisal fibre parameters on the
flexural strength and toughness and with the ultimate torsional strength and toughness of
FRC was established. It has been concluded that (i) addition of fibres have contributed
significantly to the flexural and torsional strengths and toughness of the concrete.
~erreiva e Castro and others [225] carriedout experimental investigations on the use of
sisal fiber laminae for strengthening reinforced concrete beams. Flexural tests on 2m long
concrete beams with bonded sisal laminae as external reinforcement were carriedout
(simple supported; four-point monotonic loading). The results were compared with no
external sisal reinforcement and the results generally indicate that the flexural strength of
the externally reinforced beams has increased.
Bezerra and others [226] evaluated the effect of the incorporation of different types of
synthetic fibres (PVA and PP) and cellulose pulp in the toughness and strength of fibre
reinforced cementitious composites, consisting of OPC, carbonate filler and SF.
Mechanical and physical performances were assessed for specimens ten formulations after
28 days (7 days wet curing, followed by air curing). It is found that (i) the composites with
PVA fibres showed toughness and flexural strength higher than that of PP fibres used;

(ii) PVA fibres fomlcd a strong bond with cementitious matrix due to their 'hydrophilic'
nature and geometric characterishes.
Ramakrishna and other [227] studied the workability, strength and durability of polymer -
modified sisal fibre mortar composites using three types of commercially available SBR
emulsions. The results obtained were compared with that of reference mortar specimens
(i.e. without polymer modification). It is found that there is a positive influence of
polymer-modification of matrix on the various characteristics (workability, strength and
durability) of sisal fibre reinforced composites.
.4rsene and others [228] studied the mechanical properties of natural fiber reinforced
mortar (NFRM), with focus on the influence of porosity and weight fraction of fiber, sugar
cane bagasse fibres (I-% by mass in relating to cement) were pyrolysed under controlled
inert atmosphere (at 200' c for 2 h) before incorporating them in the cement matrix.
Flexural strength, fracture toughness, water absorption, microscopy (SEM), tensile
strength of fibres, mechanical modelling of strength (based on law of mixtures and
influence of porosity on strength as reported by various authors), were investigated. It is
found that the strength and toughness are strongly affected by porosity of the material.
Raouf [229] has investigated the properties of reed (available in Baghdad) reinforced
concrete such as tensile strength, pull-out tests, dimensional stability due to successive
wetting and drying and flexural behaviour of reed-reinforced concrete slabs and joists.
Based on the experimental results, a design criteria is presented and application to low cost
houses, discussed. Long -term durability of material was also discussed.
Silva and Campolina [DO] studied the use of cement mortar and paste containing different
forms and lengths of sisal fibers. Compressive strength (cylinders), flexural strength (slabs
and prisms), tensile (cylinders, by diametrical compression) and workability. It is
concluded that (i) there is an increase in compressive strength as the fibre length increases,
upto a determined limit; (ii) the flexural strength on prisms decreased when fibres of 10
cm were used.
Uzomaka [2311 investigated the physical characteristics of akwara and akwara-reinforced
concrete (akwaracrete). It is found that (i) akwara fibres are dimensionally stable in water,
durable in a cement matrix environment, and has a low-modulus of elasticity; (ii) mixes
containing akwara have lower mobility and compatibility than their plain counterpart;

(iii) fibres improves the impact resistance of concrete, but appears to have no effect on
uniaxial compressive strength or modulus of rupture.
Coutts [232] investigated the flexural strength and fracture properties of a cement mortar
reinforced with New Zealand (NZ) flax fibres, including the effect of refining the fibres
before incorporation into the matrix. It is concluded that (i) at a fibre content of 8-10%
(by mass), flexural strengths in excess of 20 MPa could be obtained comparable to pinus
radiator fibre-reinforced
mortars. However, the fracture toughness values were
approximately half that of the P. radiator composite and so NZ flax fibres are not as
effective for asbestos fibre replacement.
Pama and others [233] have carriedout analytical and experimental investigation of the
mechanical and physical properties of wood-wool fibres. The mechanical properties were
derived based on law of mixtures and the analytical study was made by treating the
material as a composite where the cement paste acts as the matrix and the wood-wool as
randomly-oriented long fibres. Explicit expressions were derived for the various elastic
rigidities of the slabs as well as the ultimate strengths in bending, tension and
compression. Wood-wool slabs with varying wood content and wool-cement ratio were
tested in flexure, direct tension, axial compression, torsion, water absorption, impact,
permeability, combustibility, creep and shrinkage. The test results are found to be in good
agreement with the theoretically predicted values.
Sridhara and others [234] investigated the ability of fibres, such as, nylon, coir, and jute to
reinforce plain concrete, to increase its impact and shatter resistance of concrete to impact
in varying de, urees.
Ramakrishna and Sundararajan [235] experimentally investigated the strength and
workability characteristics of flyash - based fibre reinforced mortar (CFRM). Four aspect
ratios 915, 30, 50 and 70); four levels of fibre contents (0.2%, 0.3%, 0.4%, 0.5% - by wt.
of cement), four flyash contents (40%, 50%, 60% and 100%) were considered for CM 1 :3.
Flow value, cohesion (c) and angle of internal friction were determined by flow table test
and by direct box shear test. It is concluded that (i) the workability measured in tenns of
'flow values' has a positive influence due to incorporation of flyash in the mortar
composite; (ii) it is possible to achieve comparable compressive strength for the CFRM,
for a wide range of aspect ratios of coir fibres and at various replacement levels of flyash.

Ramakrishna and Sundararajan [236] have compared the strength behaviour (compressive
and flexural) of sisal, coir, hibiscus cannebinus fibre reinforced concrete with and without
using pozzolanas (GGBFS, FA - 20% by wt.), Four fibre contents (0.3%, O.4%, 0.5% and
0.6%) and fibre lengths varying from 25 - 35 mm were considered for M25 (designed
mix) concrete composites. The result obtained indicated that (i) there is general agreement
on various strength characteristics like compressive strength, with marginal increase in the
flexural strength when compared to that of reference concrete (M25).
Ramakrishna and Sundararajan [237] investigated the effect of GGBFS on the
compressive strength of coir fibre reinforced mortar (at constant flow value) with three
replacement levels (SO%, 60 %, 70%) and at four fibre contents (0.3%, 0.5%, 0.7% - by
volunle of mortar cube). It is found that (i) the compressive strength is marginally higher
than reference mortar (CM - 1:3) when 50% of OPC is replaced by GBFS and at 0.7%
fibre content and (ii) there is no reduction in the compressive strength of mortar due to
incorporation of coir fibres, unlike the case of coir fibre reinforced mortar, without
admixing GGBFS.
Ramakrishna and Sundararajan [238] investigated the workability and compressive
strength (@ 28 and 56 days) for ternary blends (OPC I- GGBFS + FA) mortar for three
mixes (1:3, 1 :4, 1 :S) with and without sisal fibres. Pozzolanic content (10- 80%) and fibre
contents (0.25% to 1.5%) were varied widely. From the results it is observed that
(i) comparable workability and strength for the ternary - blended sisal fibre mortar
composites can be attained when the FA content is 40% of the blend. Moreover, the
compressive strength is maximum in the mortar composite, when sisal fibre content is
0.5%, irrespective of the mix. It is also found that there is a positive influence on the
workability and compressive strength due to the ternary blends in sisal fibre mortar
composites, when compared to the reported behaviour of such composites, using only
OPC, as a binder.
Rarnakrishna and others [239] investigated the flexural toughness characteristics of coir
fibre reinforced concrete (M20) using un - notched beam specimens under a four - point
load system, Five fibre contents (0.3%, 0.5%, 0.7%, 1.0% and 1.5%) and four fibre lengths
910 , 20, 30 and 40mm) were considered. It is concluded that the 'toughness energy'
increases with increase in fibre contents and fibre lengths; (ii) the coir fibre concrete
composites have shown 2.04 times improvement in the energy absorbed over control or
plain cement concrete. .

Rodrigues and others [240] conducted bending tests of specimens without photoelastic
sheet to establish the fracture toughness. Considering that the notches act as initial cracks,
average values of fracture toughness were calculated for cement mortar composites with
and without reinforcement of 3% volume fraction of sisal fibres of 25mm length,
randomly distiributed. It is observed that the sensibility to the variation of the notch
geometry, foreseen by an analytical approach and observed in the transmission
photoelastic models, did not occur in cement based composites reinforced with vegetable
fibres (CCRVF), which is attributed to the presence of voids and micro - cracks. Based on
/
the inherent characteristics of cement - based materials and geometric parameters of
notches, basic fracture mechanics equations were adopted in the development of a
formulation, which predicts whether the composite would present notch sensibility or not.
Mesa Valenciano and Freire [241] evaluated the compressive strength of mortar
composites using washed (in boiling water) fibres (bamboo fibre and bagasse fibre) and
fibres submitted to chemical treatments (consisting of bamboo fibre immersion in caustic
soda for 24 hours; sugarcane bagasse fibres immersion in a 5% sodium silicate solution for
5 minutes followed by a new immersion in a 30% aluminium sulphate solution for
5 minutes). Compressive strength of composites were evaluated at 3, 7 and 28 days.
Results indicated that the compressive strength of mortar composites have decreased to a
great extent, the worst being for sugarcane bagasse. However, the strength of composite
increased after the chemical treatment.
Savastano and others [242] have discussed the performance of several non- conventional
materials based on cernentitious matrices reinforced with cellulose pulps. Clinker free
cement based on BFS ground at three different Blaine fineness, as well as OPC composites
were prepared based on fibrous resources which include eucalyptus (Eucalyptus grandis)
residual pulp, banana (Musa Cavendishii), kraft and sisal (Agave Sisalana) kraft and using
slurry vacuum de-watering process with fibre constant ranging from 8 to 12% (by mass).
MOR, MOE, fracture energy properties were evaluated at 28 days. It is concluded that
(i) residual eucalyptus fibre seems to be the better option to produce cellulose reinforced
cement sheets due to better durability and due to the use without any significant
processing; (ii) Low - alkaline slag binder seems to be a feasible option.
Toledo Filho and others [243] investigated the bending behaviour of fibre - cement mortar
hybrid composites containing glass and sisal fibres. The effect of a combined use of short

(25 mm long) and continuous (300 mm long) sisal and glass fibres, at volume fractions
ranging from 1% to 3.1% and their interaction on the flexural strength and toughness of
the mortar matrix was investigated, using factorial design of experiments. Bending tests
were conducted on specimens (300 x 60 x 12.5 rnm) using a four - point load system. The
results indicated that (i) sisal fibres were more efficient in increasing the composite
toughness, whereas, glass fibres were more efficient in increasing the composite flexural
strength; (ii) hybrid composites containing continuous sisal and glass fibres presented the
best results, increasing the flexural strength and toughness of the matrix by about 225%
and 700%, respectively.
2.5.4 Durability of Fibres and Composites
(including studies on improvement of durability of composites)
Toledo Filho and others [244] studied the durability of sisal and coconut fibres exposed to
alkaline solutions of calcium and sodium hydroxide; durability and micro structure of
cement mortar composites reinforced with the above fibres aged under tap water, exposed
to controlled cycles of wetting and drying, as well as to open air weathering. It was found
that (i) sisal and coir fibres conditioned in Ca (OH)2 solution of pH 12 completely lost
their flexibility and strength after 120 days; (ii) cement mortar composites with coconut
and sisal fibres and exposed to six months of open-air weathering or after being subjected
to cycles of wetting and drying, showed significant reduction in toughness;
(iii) embrittlement of the composites can be mainly associated with the mineralization of
the fibres due to migration of hydration products, especially Ca (OH)z to the fibre lumen,
walls and voids.
Toledo Filho and others [245] investigated experimentally several approaches used to
improve the durability performance of vegetable fibre reinforced mortar composites
(VFRMCs) incorporating sisal and coconut fibres, which include: (i) carbonates of matrix
in a Coz .rich environment; (ii) immersion of fibres in slurried SF prior to incorporation in
the OPC matrix; (iii) partial replacement of OPC matrix by undensified SF or BFS and a
combination of fibre immersion in slurried SF and cement replacement. The durability of
modified VFRMC was studied by determining the effects of aging in water, exposure to
cycles of wetting and drying and open air weathering on the micro-structures and flexural
behaviour of the composites. It has been concluded that (i) immersion of natural fibres in
a SF slurry before their addition to cement-based composites was found to be an effective
means of reducing embrittlement of the composite in the environments studied; (ii) early

cure of composites in a Co2 - rich environment and the partial replacement of OPC by
undensified SF were also efficient approaches in obtaining a composite of improved
durability and (iii) use of slag as a partial cement replacement had no effect on reducing
the embrittlement of the composite.
Castro and Naaman 113761 studied the use of natural agave fibres as possible reinforcement
for Portland cement based matrices. Two types of the above family (Lechugilla and
Maguey pulquero) were used. Flexural mortar beam specimens (300x75x12.5mm) with
SIC =1.0 and W/C = 0.6 or 0.5 (with SP) were used. Fibre characteristics, flexural
behaviour of mortar beams, long - term behaviour of the composites (load-deflecting on
curves) after exposure to seven types of environments and long-term behaviour of fibres
(tensile-strength) after exposure to the same environmental conditions as that of the
composites, were investigated. It has been concluded that (i) natural fibres of 'agave'
family have significant mechanical properties that make them eligible as potential
reinforcement in cementitious matrices; (ii) lengths of fibres upto 75mm and V ~l1% can
be mixed with the mortar matrix and that higher water contents and I or use of SP are
generally necessary to reach such limits under normal mixing conditions; (iii) elastic-
plastic behaviour in flexure and multiple matrix-cracking are achieved for Vf > 7%;
(iv) there is a strong indication that cement matrix reinforced with natural fibres can
achieve good resistance to normal environmental exposures.
John and others [7] assessed the degradation on a wall panel composite made with a low
alkaline, clinker free, activated slag cement (BFS activated by 2% of lime and 10% of
gypsum), reinforced with coir fibres that has been in use in a small 12-year old house at
Sao Paulo, Brazil, from the internal and external walls of it. Fibres removed from the
above composite (ie., walls) were cleaned and were subjected to BSE - SEM (back
scattering electron-scanning electron microscope), EDS analysis and matrix
transformations by XRD, TG and DTG analysis.
It was found that no significant
differences exist in the lignin content of fibres from external and those removed from
internal walls.
Sreenivasan and others [246] exposed coir fibres to an 18% NaOH solution for 30 minutes
at 30°C and observed a weight loss of 12 %.
The weight loss was attributed to
de-lignifications, but , probably included removal of fibre extractives. This treatment
caused a small increase in the tensile strength. As there was no measurement of variation

in lignin content and as the alkaline exposure caused the fibres to shrink in length and
swell in the diameter [247, 2481 it was difficult to draw any conclusion.
Rout and others [249] exposed coir fibres to a 10% NaOH solution and found that there
was an increase in tensile strength. However, a significant reduction in tensile strength
was observed, when previously de-waxed coir fibres were subjected to alkaline exposure
(i.e., 5% NaOH solution @ 30°C for Ih.).
Gram [5] performed the first systematic and comprehensive investigation on the durability
of sisal and coir fibre reinforced Portland cement. The degradation of fibres in alkaline
environment was evaluated by exposing the fibres to alkaline solutions and measuring the
variation in tensile strength. The investigations included natural aging of thin sheets in
Dar El Salaam and Stockholm and different accelerated aging tests like CBI (cycles of one
surface subjected to cyclic wetting and drying), 'Finish Climate Box' (immersion @ 50°C
water followed by 3h at 20°C, 95% RH), wet and dry cycles at 20°C for upto 40 months,
continuous exposure to laboratory environment at 20°C and continuous immersi~n in
water at 50°C. It has been concluded that (i) wet -and-dry cycles increased the rate of
degradation due to the transport of OH-ions due to movement of water, which dissolve the
lignin and rinse out the decomposed lignin; (ii) samples exposed in hot climate (i.e., at Dar
El Salaam; Tanzania) suffered move intense degradation than those exposed in cold
climate (i.e., at Stockholm, Sweden); (iii) carbonation of the matrix seemed to presenie the
fibre strength.
Finally it was concluded that the reduction of the toughness of the
composite is caused by fibre de-lignifications due to the alkaline cement's pore water.
However, no direct measurement of lignin content, before and after exposure, was
performed.
Bio-deterioration of cement-bonded wood particle-board has been investigated by Souza
and others 12501. These products contain much higher fibre content than cement
composites. Mechanical (strength) degradation was observed even though, there was
fungi growth in the sample / (s).
Mohr and others [XI] investigated the effects of three fibre treatments - beating,
bleaching, drying on Kraft pulp fibre-cement composites, which are subjected to wet / dry
exposure and at 78 days. The performance of the above composites after the specified
number of cycles was assessed by centre - point bending tests and further characterization

of the composite and the failure-mode was assessed by SEM of the composite fracture
surfaces.
Ramakrishna and Sundararajan [252] have presented the results of an experimental
investigation on the variation in chemical composition and tensile strengths of coir, sisal,
jute and Hibiscus cannebinus fibres, when they were subjected to alternate wetting and
drying and continuous immersion for 60 days in three mediums (water. saturated lime and
sodium hydroxide). Compressive and flexural strengths of CM (1 :3) specimens reinforced
with the above fibres (in natural dry condition and in corroded condition) were determined
after 28 days of normal curing. From the results obtained it has been concluded that
(i) there is substantial reduction in the salient chemical composition of all the four fibres,
after exposure in the various mediums; (ii) coir fibres retain higher percentages of their
initial strength than all other fibres; (iii) strengths of the above natural fibre reinforced
mortar specimens reinforced with corroded fibres are less than the corresponding strengths
of reference mortar.
Berhane [253] had discussed the difficulties encountered in the production and use of
natural fibre reinforced mortar roofing tiles and the means of reducing the adverse effects
of Portland cement hydration products on the performance of natural fibres in mortar.
OPC, SF, natural pozzolanic (Scoria and pumice from the Ethiopian rift valley) powders
as binders; natural sand and two volcanic ashes (scoria and pumice) passing through 2 mm
sieve; sisal fibres (10 rnrn, 2% - by vol. of total mixture) and WIC = 0.55, were used.
Mortar specimens (400 x 250 x Smm) cast and cured (7 days in water; 21 days in
controlled conditions where temperature was 20°C and RH = 60%). Small prisms (250 x
50 x Snim) cut out from the above specimens were tested for its durability (mid-point load,
flexural test) after 28 - 730 days of exposure to the prevailing Addis Ababa weather. It has
been concluded that (i) natural pozzolanic materials (available in the Ethiopian rift valley)
have a protective effect on the natural fibres in mortar; (ii) there is no sign of degradation
of mortar composites reinforced with sisal fibres even after two years, when 40% of
natural pozzolanic materials were used to replace OPC, (iii) mortar composites with only
OPC lost almost all their ductility within 6 months.
Canovas and others [254] carriedout investigations with the aim of solving the problems of
vegetable fibre mineralization in cement. mortars consisting of (i) pore sealing,
mechanical strength and alkaline reduction, (ii) fibre impregnation. Mortar composites
with or without admixtures were reinforced with sisal fibres impregnated or

unimpregnated under different conditions. Compounds derived from timber, insoluble in
water and unextractable by water or water vapour. It has been concluded that
(i) efficiency of alkaline reduction, mortar pore sealing 1 reduction in water absorption in
mortars as well as in fibres have been found to be good.
Bergstrom and Gram [255] investigated the alkali - sensitiveness of glass and sisal in
cement systems. Specimens of cement mortar reinforced with alkali-resistant glass fibres
(Cem-FIL2) or sisal fibres (unimpregnated as well as impregnated) have been subjected to
aging by two different methods (BRE-method and CBI-method). The durability has been
evaluated by flexural strength studies. It has been concluded that sisal fibre reinforced
concrete also gets brittle with time, but this process can be delayed by protective
impregnations of the fibre and nearly inhibited when the alkalinity of mixture is reduced
when SF is used to replace part of OPC in the matrix
Sanjuan and Toledo [256] evaluated the effectiveness of crack control at early age on the
corrosion of steel bars in low modulus sisal and coconut fibre-reinforced mortars. Mortar
samples with reinforcing bars were subjected to early drying after casting, to develop
cracks in the vicinity of the bars, and then held at 100% RH at room temperature for 40
days when they were exposed to a chloride solution to enhance corrosion rate of steel bars.
Corrosion of steel bars was monitored by electro-chemical measurements and observations
of crack development, It has been found that (i) natural fibres perform well in controlling
in mortars and also seem to delay slightly the iniation of corrosion of embedded steel bars;
(ii) self-healing of cracks is more effective in smaller ones, and therefore in natural fibres,
reinforced mortars present a higher self-healing behaviour.
Mwamilla [257] has described that the deterioration mechanism of fibre constituents is
both mechanical and chemical bondage of the fibre constituents through several factors
and that dis-advantage of low-modulus of elasticity can partially be offset by adoption of
drying under load and stress-relief techniques.
Gram and Nimityongskul [258] studied the effect of rice husk ash (RHA) on the durability
of natural fibres, such as, sisal, manila, hemp, ramie and coir in a cement-pozzolana matrix
specimens (280 x 390 x 8mm) prepared with mortar (1:2:0.5; binder: aggregate: water, by
wt.) incorporating Vf= 2%. The above specimens were exposed to climatic conditions in
Thailand and accelerated ageing. A parameter 'B' - defined as the post - cracking stress at
either maximum stress after passing the limit of proportionately (MOR) or the stress at 1 %

strain depending on the stress-strain curve was adopted to determine the improvement in
durability of the composite. It is found that the durability of the above fibres has improved
due to partial replacement of OPC by RHA in the matrix.
Berhane [259] after reviewing the durability problems of natural fibre mortars and that of
roofing sheets, has stated that the problem of durability of fibres is more serious in tropical
countries than those located in the temperature regions. It has been suggested that the use
of locally available pozzolanic materials can be advantageously used to improve the
durability of the material.
Abdel - Rahman and others [260] investigated:(i) the anatomic structure of the date palm
frond (DPF) stalk cross - section, its dimensional stability and mechanical properties ;
(ii) the durability of stalks in fresh concrete; (iii) the long- term durability of DPF stalks in
fresh concrete in cement - water mixtures for 120 hours. Concrete beam specimens with
embedded DPF stalks were used to assess the long-term durability of the stalks in
hardened concrete and the effect of aging was determined by direct tensile strength of
stalk specimens, rather than, flexural strength of such beams. The long - term durability of
stalks in concrete were assessed based on the effectiveness of DPF stalk coated with either
varnish, bitumen or sulphur. It has been concluded that (i) there is substantial increase in
volume due to 100% water absorption; (ii) DPF fibres suffer no durability problem in the
alkaline medium of fresh concrete. (iii) varnish coating of DPF stalks results 1 in excellent
long- term durability characteristics.
Shafig [9] and others investigated the durability of oriented and randomly distributed jute
and ramie fibre mortars using RHA as a pozzalana. RHA was used to replace upto 40% of
OPC and Vf used was 2.0. The mortar specimens were subjected to simulated aging
(alternate wetting and drying) upto the number of cycles=120. It has been found that
(i) it is possible to improve the durability of natural fibre reinforced mortar and it is found
that the optimum amount of MA content = 30%; (ii) one cycle of simulated aging process
which involves 30 minutes of water spraying and 5 % hrs of drying in an oven at 105°C is
equal to 1 % months of exposure; (iii) post - cracking strength of their plates having
oriented fibres is remarkably higher than those of thin plates reinforced with chopped
fibres. The toughness and ductility of the fibre reinforced mortar are also very high when
compared to those of unreinforced mortar; (iv) specimens reinforced with ramie fibre are
stronger than those reinforced with jute fibres, regardless of the amount of RHA content
and number of aging cycles.

Macviar and others [261] examined the effects of laboratory - scale accelerated aging
exposures on the changes in physical mechanical properties of commercially produced
cellulose fibre - reinforced cement composites (i.e. sheets). Two different aging methods
(accelerated carbonation method, cyclic freeze - thaw method) were used to simulate the
possible aging mechanisms and the material compared, with a natural weathering after
5 years as roofing sheet. Porosity, water absorption, permeability of nitrogen, compressive
shear strength, examination of fractured surfaces in SEM, were carried out. It has been
concluded that (i) the compressive strength of the accelerated aged composites can be
related to the micro - structures within the composite; (ii) substantial reduction in porosity
and water absorption can be achieved by accelerated carbonation aging tests ; (iii) both
natural weathering and accelerated aging in C02 environment enhanced the durability of
the composites; (iv) the aging test based on carbonation seems to be more suitable than
freeze -thaw cycling, simulating the aging the performance of the above composite.
Fisher and others [207] have reported the preliminary findings of the long - term durability
of cellulose fibre reinforced concrete (FRC) pipes for use in sewage applications, by
exposing samples of the above pipes and steel reinforced concrete to sewage environments
and the characteristics of the samples were exposed to three testing environments;
(i) aerobic bio-degradation; (ii) anaerobic degradation; (iii) sulphuric acid testing. It has
been found that
(i) while the mechanisms of degradation have been similar , FRC
material is less favourable in all environments tested; (ii) the strength of characteristics of
the samples were only slightly affected ; but, the surface characteristics of materials
changed significantly.
Marikunte and Soroushian [262] carriedout a compressive experimental study on the long
- term performance of cellulose fibre reinforced cement composites subjected to
accelerated wetting - drying and hot - water soaking conditions.
An experimental
program was developed based on the statistical method of fractional factorial design
considering fibre variables. Cellulose fibres were of two types; (i) southern softwood Kraft
(SSK) and (ii) northern hardwood kraft (NSK). It has been concluded that (i) accelerated
wetting - drying has slightly improved the flexural strength of the composites, at all fibre
contents; (ii) there are significant effects of aging on flexural toughness, where toughness
reduces considerably with aging (25 cycles of wetting and drying; (iii) only fibre contents
influence the aging effect on flexural toughness (at 95% confidence level) and that the
adverse effects of aging on flexural toughness were reduced at lower fibre contents;

(iv) hot - water soaking has slightly improved the flexural strength at all fibre- contents
and that there is significant effect of aging on flexuraI toughness.
John and others [263] studied the durability of coir fibre mortar composites containing
alternate cements, mainly based on BFS and RHA (i.e.) 1:1.5; 0.51- BFS cement: sand;
water) Vf= 2% was adopted and setting time, workability, impact strength were evaluated.
Three types of durability test, (Q-C-T: quick condensation test; accelerated carbonation
test and natural weathering for a few years at Sao Paulo, Brazil) were conducted. It has
been concluded that it is possible to increase the durability of vegetable fibres only by
changing the matrix composition and that it is possible to produce load -bearing panels
with vegetable fibre reinforced materials.
Canovas and others [264] studied the effect impregnation of sisal fibres on water
absorption and flexural behaviour of cement mortar composites. Natural impregnates
considered are: (i) colophony + turpentine; (ii) clove oil + Xilene + turpentine + alcohol;
(iii) tannin + alcohol +Xilene. The performance of impregnated sisal fibre composites
were also compared with that of unimpregnated sisal fibre composites,. It has been
concluded that (i) use of colophony as an impregnant has proved to be successful when
compared with the mortar reinforced with unimpregnated fibres and the results obtained
are as good as those obtained using other impregnents; (ii) reduction of permeability and
the flexural resistance increases with heating which indicates the reduction of alkalis in the
mortar.
Oliveira and Agopyan [265] evaluated the composite behaviour of malva fibres
(Urena lobata Linn.) with time in cement mortar. The fibres were subjected to treatment
with simple washing (with ordinary washing - up liquid) and impregnated with linseed oil.
Behaviour of composites with and without treated fibres were studied by their tensile and
impact strengths (direct falling weight impact test). The results have shown that (i) the
composite reinforced with fibre washed with ordinary washing-up liquid behaves better
than other composites; (ii) composites using treated I untreated fibres show similar
behaviour up to 60 days. However, there is a higher decrease of strength of composites
with untreated fibres; (iii) it is possible to improve the durability vegetable reinforced
composites, by this simple technique, in addition to the techniques like sealing the
composites and using BFS based binder, as suggested by various earlier investigators.

Agganval [266] studied the durability of coir fibre reinforced cement board by subjecting
it to accelerated durability tests along with resin - boarded particle boards and ply wood
(commercial product). The physico- mechanical properties like thickness swelling, water
absorption, bending strength and internal bond strength of the exposed samples were
determined before exposure, and at varying intervals upto the completion of weathering
cycles. Three types of weathering cycles (A,B,C) were carriedout following the
procedures laid down in IS : 2380-1963 (for A, B) and IS:1734-1983 ( for C): It is
concluded that (i) the thickness and internal bond strength of coir fibre cement boards
remain unchanged and that there is slight change in water absorption and bending
strength; (ii) resin - bonded particle boards showed appreciable increase in thickness and
water absorption and decrease in bending strength and internal bond strength under similar
exposure conditions; (iii) no delamination and disintegration greatness of coir fibre cement
boards are observed in boiling water test; (iv) the developed boards can be used for
various applications, in buildings such as, panelling of door and window shutters,
partitioning , false ceiling, cladding with advantages of using wood working tools,
painting and lower cost compared to good quality wooden shutters
Fischer and Bullen [267] studied the durability of cellulose fibre reinforced concrete pipe
material to extremely aggressive acid environments and the performance was compared
with steel reinforced concrete pipe. Strength change in mass, wall thickness and surface
characteristics were used performance indicators. Based on preliminary test cements, it has
been concluded than the performance of cellulose fibre reinforced concrete pipe material
is comparable or superior to that of steel reinforced concrete pipe.
Fischer and Bullen [268] have sutdied the permeability and sorpitivity as durability
indicators for cellulose fibre reinforced concrete pipes. Three FRC materials (normal
production material from Farnes Hardie FRC pipe material, experimental mixes with
different fibre 'freeness' and bitumen coated FRC as employed in soil-waste systems,
were investigated, with air-cured concrete pipes as a reference. It is found that
permeability is higher in FRC while sorptivity is of the same order as that of
(unreinforced) air-cured samples.
Gram [269] studied the durability of sisal (long vegetable fibres and cellulose (pulp) fibres
in cement based matrices. Specimens made of sisal fibre concrete for durability tests were
treated with impregnating agent (formine and steric acid) and the matrix (OPC) was
admixed with (SF -20 to 45% and 67% flyash). The composites were subjected to two

types of aging environment and the durability evaluated by flexural strength. It has been
concluded that (i) embrittlement of sisal fibre concrete can be avoided almost completely;
(11) the long-term properties can be improved by reducing the alkalinity of concrete pore
water by replacing 45% OPC ~ ith SF; (iii) high alumina cement, instead of OPC will slow
the degradation of sisal fibres; (iv) the alkalinity of cellulose fibre composite can reduced
by replacing part of OPC with SF or completely by high alumina cement. (iv) the results
from actual outdoor environments have to bee concluded with accelerated test
environments used in the study.
Shaman and Vantier [270] carriedout durability tests in conjunction with natural
weathering studies on .4C , absorbs/wood fibre cement, and wood fibre reinforced cement
sheets. Exposures were carriedout on both unpainted / painted materials. Mechanical
properties after one year were evaluated and compared with both types of exposures
MOR, MOE, tensile strength, internal bond strength, impact strength and moisture
movement were evaluated. It is concluded that (i) asbestos, wood fibre and wood fibre
cement showed increases in moisture movement; MOR, tensile strength and moisture
movement, respectively; (ii) painting of all faces of exposed sheet suppressed the
mechanical changes; (iii) weathering behaviour of cellulose fibre reinforced cement
composites is dependent on pre-treatment of fibres and on curing method used for the
matrix; (iv) autoclaved wood fibre reinforced cement sheet based on Kraft pulp will be
durable during service life.
Delvasto and others [271] treated fique fibers by chemical procedures (treatment with an
organo-siliane) coupling agent and exposed to strong and acid media. The efficacy of each
treatment was evaluated by measurements of the diameter variation, tensile strength of the
fiber, elongation at break and SEM observation of fiber topology. The results of this
treatment were compared to those obtained by the treatments of sulfonation, impregnation
of the virgin fiber with silane A 1100 and the untreated or virgin fiber. It is found that (i)
the coating of virgin fique fiber with silane A 174 did'nt generate any positive protective
action; (ii) best behaviour is obtained when silane A 1100 is used.
Gram [5] investigated the reasons for the observed embrittlement of sisal fibre concrete
and for finding suitable counter measures, under a joint venture project between the
Faculty of Engineering at the University of Dar es Salaam (Tanzania) and the Swedish
Cement and Concrete Research Institute. Flexural strength of thin beams reinforced with
long fibres and the stress at a deformation of 1% or the maximum stress when the

proportionality limit has passed have been used as a criterion for evaluating the touglmess
of the composite. Sisal fibre concrete was subjected to three types of aging (laboratory,
outdoor and climatic box). It has been concluded that (i) embrittlement of sisal fibre
concrete can be completely avoided by replacing at least 40% of OPC and SF, (ii) other
ways of reducing the alkalinity of the pore water by adding gypsum or replacing the binder
with high alumina cement have had a favorable effect: (iii) embrittlement of sisal fibre
concrete in the laboratory by sealing the pore system in the matrix internally with the aid
of wax: (iv) protective impregnation of sisal fibre with barium nitrate and stearic acid or
formine and steraric acid does not prevent embrittlement process. (v) building of fibres
does not prevent the composite from becoming embrittled: (vi) Flax and coir fibres appear
to be more resistant in concrete than sisal and jute fibres, among the other fibres (namely
coir, fibre, flax) considered.
Sarnarai and others [272] carriedout investigations relating to chemical characteristics on
fibres, so as to obtain data needed for identification of Iraqi reed for their use in building
industry. It has been concluded that (i) reed with the exception of T. latifolia have a
resistance to fire, insects and fungi.
Sarja [273] has highlighted the requirements of various properties and their modification
of wood fibres for use in concrete for different kinds of use, such as, in load / non-load
bearing structures.
Singh 12741 investigated the durability of banana , coir, hemp, jute and sisal fibres by
exposing them in deci-normal solution of sodium hydroxide and saturated dispersion of
lime in water, by subjecting them to sixty cycles of wetting and drying. Fibre extracted
from fibre concrete roofing sheet at the end of 10 years outdoor exposure has also been
examined for changes in strength due to weathering. It is observed that (i) sisal jute and
banana fibres decay soon in alkaline environment; (ii) coir fibre is found to possess
adequate resistance to alkali; (iii) use of water repellants, ultra fines, silica fumes and
pozzolanic cements have also been discussed in lowering the alkalinity of fibre-cement
composites and consequently the embrittlement of fibres.
Ramakrishna and Sundararajan [275] investigated the effect of a few pozzolanic materials
(fly ash and GGBFS) on the strength (compressive, flexural) of sisal fibre reinforced
concrete. A mixture of locally available resin (CNSL resin cashew nut shell liquid resin)
and turpentine was used and the mixture heated to 80 - 120 C to impregnate the sisal

librcs. M25 (designed mix) was considered and OI'C was replaced by GGBITS (lo%,, 20%)
- by volume) and in blended form (15% GGBFS and 5% Flyash) and the strength of the
composite evaluated at 28 days of normal curing. It is concluded that (i) the novel
treatment process for sisal fibres have helped to recover the compressive and flexural
strengths, irrespective of the use of pozzolanas or not, indicating that there is a positive
role played by tlie above trcatrnent process to overcome their 'e~mbrittle~iie~it'
characteristics in the alkaline environment.
The effect of yeast - blended water on the pH, workability (compaction factor - CF) and
strength characteristics (compressive and flexural strengths) have been experimentally
investigated for sisal fibre reinforced concrete (M20) [276]. Three fibre contents (0.25%,
0.5%. and 0.75% - hy vol~imc of cot~crctc) and thscc fibrc Icngtlis 920. 30 and 40mn1)
were considered. 'I'he results obtained indicated that (i) it is possible to reduce pl-1 ol'the
concrete composite by replacing plain water partly by yeast - blended water;
(ii) compressive strength of the co~nposite is not affected, whereas , there is substantial
improvement in the flexural strength, indicating the positive role of yeast - blended water
i1i iniproving the niatris charnctcrislics, thus creating a conducive cnvil.onrnci~t Sol. sisal
fibres to play their elli.clivc rolc in concetc, that oi'improving the llcxusal strength.
Ramakrishna and Sundararajan 12771 investigated the effect of yeast - blended water and
GGBFS on the workability and compressive strength of san fibre reinforced concrete. M20
(designed mix) containing 30% (by wt.) of GGBFS and san fibres (0.396, 0.5%, 0.6% - by
volumc of concrclc) were considcscd and tlicir comprcssivc strcngtlis cvaluatcd at 28 dnys.
Based on pl-1 values and the workability and strength cliaractcristics attained it is
concluded that (i) there is reduction in pH to about 10.6 using yeast - blended water;
(ii) there is improvement in the workability of san fibre reinforced concrete, due to the
addition of yeast - blended water; (iii) the presence of yeast - blended water and GGBFS
has contributed to cnlinnccmcnt in thc comprcssivc strcngtli of the concrctc composite.
2.5.5 Products Based on Natural Fibres
Agopyan and others [278] have presented the most relevant results of 20 years of research
activities in the field of vegetable fibre composites, by the research group in S5o Paulo,
Brazil. Three types of fibres, namely coir (cocos nucifcra) residual fibres, sisal (Agave
Sisul~nu) field by-product and waste liucalyptus gratidis p11lp were ~~scd in granulatecl

last furnace slag (GBFS) activated by hydrated lime and natural gypsum / phospho-
gypsum to produce two types of compounds, namely, wall panels and roofing tiles.
Hollowed load-bearing wall panels developed were tested, a prototype of a low-cost house
(120m2) assembled and an accelerated aging test (quick condensate tcst: Q-C-T) prepared
on sample specimens. The prototype is found to have undergone no further degradation,
except leaching, showing presence of gypsum, a product of cement carbonation, but, with
sound fibres. For tiles 1 :l.5 (binder: sand) was used and three point bend test, warping,
water tightness and water absorption were determined and field exposure at various
ambient conditions.
It has been concluded that nat~~ral aging under tropical climatc
conditions played a significant role in reduction in load support and embrittlement of
fibre-cement roofing tiles.
Baradyana, [279] has described the experimental efforts in the production of roofing
products and 750 x 750 mm corrugated sisal fibre concrete roofing sheets and in the
construction of 12 demonstration houses built with the above materials.
above products for third-world development have also been highlighted.
The potential of
Guimaraes [280] has summarized the research on vegetable fibre - cement composites as
applied to Engineering purposes (in Brazil) encompassing: (i) determination of physical,
mechanical properties of fibres from sisal, coir, bamboo, piassava and sugar -cane
bagasse; (ii) influcncc of Ttbsc paramclcrs (I,l,VI), ptop~rlio~li~ig nnd cnsting pioccsscs on
the flexural strength, absorption and specific gravity of the composites; (iii) casting of
dwelling components by simplified processes of roof tiles, flumes, kitchen sinks , water
tanks and improvement of durability by polymer impregnating agent. Two impregnating
agents, namely, (i) polyvinyl alcohol (PVA) - an aqueous solution and (ii) dymethyl
formanidc (DMI:) varyi~ig conccntsations; @25T ) wcsc cmploycd on sisal iibtcs. It lias
been found that impregnation has reduced the tensile strength of sisal fibres.
Pararnasivam & others [281] have carriedout a feasibility study of making coconut fibre
reinforced corrugated slabs for use in low-cost housing, particularly for developing,
countries. A simple and a practical method - 'pulling technique' has been developed for
producing corrugated slabs. Third - point loading was used to obtain the flexural strength,
load - deflection curves (Vf = 2- 4%; Lf = 12.5, 25, 38.0 mm). Thermal and acoustic
properties were also evaluated. It has been reported that a flexural strength of about 22
~lrnrn~ is obtained using Vf = 3.0% and Lf = 25mm; (ii)
the performance of coconut fibre

einforced boards is comparable to that of asbestos boards and hence should be considered
seriously for use in low- cost housing, particularly for developillg countries.
Suzuki and Yamamoto [282] have studied the creation of incombustible materials by
mixing sub - standard flyash with plants and their fibres and also production of
incolnbustiblc building light - wcight building malerials by combined usc ol' water -
soluble ceramics. Rice husk, cotton waste, bamboo (5 x 5 mm square bar and chips there
of ) , pulp - wood chips (from paper mill), flyash , boric acid fluoride (water soluble
inorganic polymer), clay mixtures, cement were used to produce blocks, boards. It has
been concluded based on strength and flammability test that incombustible granulated
sand can bc l>rod\~cc.rl Il.om pianls nlid Lhcir librcs anti that the newly ticvclopcd wntcr -.
soluble ceraniics is deemed to be useful to make materials incombustible.
Filho & others [210] studied the application of sisal and coir fibres in 'adobe blocks',
using two types of water repellant treatments. Two types of locally available soils at
Paraiba, Brazil, were considered. The stress - strain behaviour of the adobe blocks
produced nianually without and with sisal and coconut libres, considering different
waterisoil percentages, have also been investigated. It has been concluded that (i) 4% of
sisal and coconut fibres is found to improve the brittle behaviour of 'adobe blocks'
substantially; (ii) there is a need for further studies to establish the optimunl fibre length
and fibre content for use in 'adobe blocks'; simple process for the production of the adobe
blocks; thc usc of n soil stabilizer (likc flyash or limc).
Mattone [283] investigated the behaviour of thin panels of gypsum reinforced with either
sisal or coconut fibres. Vacuum process was used to prepare specimens and bending and
impact tests perfbrmed on them. The performance of the above panels was compared with
that of gypsum panels reinforced with glass fibres and a commercially available gypsum
board. Vcgct:lhlc Cibrcs wcrc nddcd to tlic gypsum slurry with a volumc li'aclion VI.= 4%.
, >
1 he results revealed the good performance of gypsum composites reinforced with
vegetable fibres and that' they can be used as a viable alternative in lieu of gypsum - board
or panels reinforced with glass fibres.
Schafer and Brunssen [284] have described the manufacture of lost formwork system for
floor slrtbs rcinforccd with sisal fibrcs and its load - carrying bchaviour. 'l'wo lypcs of
fornlwork elements (arch - shaped and trapezoidal) were considered and their load -
carrying capacity determined. From the investigations it has been inferred that (i) sisal

fibre reinforced elements can serve as components of a form work system; (ii) sisal
present in thc compression zone of slab should not be considered as load - carrying, duc to
low moit~~lus of'claslicily and low co~nprcssivc strength; (iii) arch -- shapcd clemcnts arc
preferred for formworl< system due to high load - carrying capacity and easy of
production.
A1 - Makssoi and Kasir [285] evaluated papyrus - cement composite board as a
construction niaterial. Bending, tensile strength pcrpcndicular to the surfncc (internal
bond), comp~c~~ivc strcngtll pal.nIlcl to tile s\~rfi~cc, LVIIICI. i11~0rpli011 i111ci
swelling were evaluated. Two lengths (20cm , 30cm) of papyrus and two target density
(1200kg/m3 and 800 kg/m3) were considered at replacement level of 20% (by ut.) of
cement. It has been concluded that the most desirable combination of cement - bonded
composite board would be high density and small size of papyrus (Typha domingensis L.)
unless tensile strength perpendicular to surface (I.B.) is the principal concern.
Acevedo and others [286] investigated various agricultural fibrous residues common in
Chile (wheat fibre, barley fibre, maguey fibre and curaguilla) for production of natural
fibre concrete roofing tiles. Flexural strength, impermeability and water absorption were
evaluated. It has been found that it is possible to produce roof tiles according to Chilian
standards using (hc abovc vcgclablc librcs.
Agopyan and John [287] studied the production method and performance evaluation of
hollowed wail panels made with vegetable fibre reinforced alternative cement, bascd on
BFS activated with lime and gypsum (dehydrate). The matrix used was mortar (l:l.j,
alternative cement: sand), with coir fibres (2%, by vol.) as reinforcement. Compressive
strength test, impact test and pull ----outcst wcrc pcrli)rmctl on rllc pancls. It hns bccn
Il~icli~l~~~
concluded that (i) the panels possess enough n~echanical strength for load - bearing walls,
despite the durability problems; (ii) the strength of the panel is for higher than the one
required for one floor (1 MPa); (iii) long - term durability results should be considered
before the panels are used in multi - storeyed buildings.
Saxena and others [288] explored the possibility of utilising sisal libres for production of
composites for use as roofing material in lieu of asbestos cement components.
Optimisation of various,pararneters, such as, W/C ratio, Lf, casting pressure, curing time,
shape and gauge of steel mesh by conducting flexural strength test were carriedout. The
performance of sisal fibre cement sheet and asbestos sheet were carried out, considering

water absorption, breaking load, weathering (indoor/outdoor), water impermeability, acid
resistance and frost cracking. Finally, it has been concluded that (i) breaking load of the
sheet at a span of one metre comes to 70-80% of AC sheet; (ii) sisal fibre cement sheet has
a great scope for substituting AC sheets, considering repairability, lower water absorption,
impcrviou~ nature, easy processing, safety to human life and economy.
Sande and others [289] investigated the composition, manufacture and various physical
and mechanical properties of sisal fibre reinforced roofing tiles, obtained from fire
manufacturing facilities located in Ivory Coast. Weight, water absorption, damp -proofing
characteristics, impact test, nib load test, bending test were used to compare the
performance of the tilcs. Based on the above, thc cluantity of mixing watcr, non-uniformity
in thickness, non-uniformity in mechanical properties have been found and hence proper
quality control measures according to ILO guidelines were recommended for the
production of quality tiles.
Pires Sobrinho [290] studied the comparative performance of prismatic specimens of
composites subjcctcd to flcxural and impact tcsts by varying matrix type, Lt, fibrelmatrix
relative volume and mixture processing. Two matrices (gypsum plaster matrix,
waterigypsum ratio = 0.5 with citric acid as a set- retarder @ 0.5%; cement plaster,
wic = 0.5), two types of fibes (sisal, d = 0.22mm; coconut, d = 0.34mm), fibre parameters
(fibre I matrix relative volume = 1 - 3%; Lf = 2- 8cm), two mixing processes (randomly
oriented fibre in the matrix; alignment of fibres in the mould to form a sandwich i.e.
plaster), fibres plaster, fibre, plaster pattern, were the various parameters considered.
Tensile strength, flexural strength (load Vs deformation) impact (Charpy's) test were
performed on the specimens. The results indicate that (i) simple addition of the above
fibres to gypsudcement matrix changes the brittle behaviour permitting a ductile
behaviour;
(ii) the influence of various parameters can be evaluated through flexural
tcsts, as an altcrnativc from to the direct tensile test and help In thc dctcrrn~nation of
characteristics values of behaviour i.e. the critical length (1,) and the critical fibre volume
(V,,) for the composites.
Manjit Singh [291] investigated the properties and applications of gypsum - bonded fibre
reinforced boards, using calcined gypsum, RFS, flyash and OPC for the production of
water ~.csislant gyp~~1111 binder which wcrc rcinlbrccd with ~ialurol librcs (sisal, coil,
bhabhar, mestha) apart from E- glass fibres, to get gypsum boards. Gypsum bonded
p~icle boards, gypsum - plaster boards, gypsu~~i - fibre boards, European resin - bonded

particlc boards, wcrc cvaluatcd for their dctisity, MOIt, MOE, bend strength and thicl

grass fibres showed the greatest promise as a reinforcing material; (ii) elephant grass fibre
displays olily Hookean elasticity characteristics; fails in a brittle mode, has a tensile
strength of 180 ~ imrn~, a nlodulus of elasticity of 512 ~c'irnni~; is not adversely affected by
alkaline and rotting environments and has acceptable levels of miscibility and bonding
with cement; (iii) elephant grass fibres improve the flexural and impact strength of a
cement sheet.
Krisl1nan1oorthy [296] has investigated the necessity and feasibility study of coir fibre
reinforced cement corrugated roofing tiles (replacing the rnangalore tiles). Six series of
COII librc 1~cin1i)sc~d corrugated tilcs ol'si/c 330 x 500 mrn consisting ofcightccn tilcs in
each series were cast. Three groups of CM 1:3 with and without flyash (0, lo%, 20%
replacement of cement) have been used. In each group of mortar 50 mm and 25 mm length
of coir fibres had been used. Breaking load, water absorption and permeability tests had
been conducted on the coir fibre reinforced corrugated tiles. It is found that (i) there is
good cosrcla(io11 bc!wccn Ihcosctical and cxpcrimcntal values of' ull~matc load;
(i~) worlting load - carrying capacity was also well above the permissible live load of 750
Jim2 on inaccessible roof; (iii) cost of coir fibre reinforced tile is also less than that of
Class A and Class AA Mangalore tiles; (iv) Coir fibre corrugated roofing tiles can be used
in place of Mangalore tiles.
1,cwis and Mil.ihi\galia 12071 macic :\
con~parisoi\ bctwccn ccnicnt roofing sliccts
reinforced with asbestog fibres, elephant grass and sugar cane residue, on the basis of
some physical (consistency) and mechanical properties (impact, flexural, thermal
conductivity, combustibility, sound tra~ismission) and derived costs. It is found that the
grass fibre sheets are found to be attractive choice
Coolc and otlicrs [298] liavc discussed thc ~ ~ of s c randomly distribulcd short coir librc
reinforced cement colnposites as low cost materials for roofing. Fibre length, fibre volume
and compacting or casting pressure were rhe material parameters considered. Bending,
impact, permeability, water absorption, combustibility and dimensional stability tests were
performed in accordance with ASTM standards. It is found that (i) a composite with fibre
length of 37.5mm, a fibre volume of 7.5% and casting pressure of I67 MPa as optimum;
(ii) this composite is substantially cheaper than either corrugated galvanized iron or
asbestos- cement sheeting and comparable in cost with other low cost roofing such as
bagasse - thermoset composites.

Gore [299] has given a brief review of the studies on natural fibre reinforced concrete and
mortars and linally listcif [lrospcctivc applications and ranges oi' possible future
devclopme~~ts which make natural fibre (NF) based concrete and mortar an exceedingly
superior composite material. He has also emphasized that the range of applications is
especially important for infrastructure development in India and other developing
countries as it brings down costs, energy consumption and increases the use of local
~ii:~~c~.ii~l~
;IIICI ~l\ills
Alade and Olutoge [300] have examined the use of bamboo fibre as reinforcement in
cement mortar (1 :3) roofing sheets. Bending test, impact test, water absorption rate test
were conducted. It is concluded that (i) bamboo fibre can be used as reinforcement in CM
for the production of roofing sheet upto 5mm thick; (ii) the cost is less than asbestos
rooling shcct and coconut fibre scinfbrcing shect, substantially.
2.5.6 Miscellaneous Studies / Review Works
'I'olcdo and others [301] experimentally ilivestigated the free, restrained and drying
shrinkage of cement mortar composites with vegetable fibres, i.e. with coir and sisal
fibres. I'he spccimcns wcrc s~ibjcctcd to wind specds ranging fio~n 0.4 - O.5mls a1 40°C
tcmpcrature and RH = 100%, upto 40 days and 320 days in a controlled environment. The
influence of curing period, mix proportions and partial replacement of OPC by GGBFS
and SF on the drying slirinltage of the above natural fibre mortar co~nposites were
investigated.
Finally an equation using the recommendation of .4CI model B3 for
concrctc was suitably ~nodificd for thc abovc case or compositcs, Ibr predicting tlic drying
shrinkage. It has becn rcportcd that tlic pscdictcd and cxpcriment rcscilts compared well.
Savastano Jr. and others PI$& examined the microstructure of composite materials
containing fibrous wastes (as reinforcement in GBFS or OPC matrices). Both secondary
and back-scattered electron imaging and energy dispersive x-ray spectroscopy were used
for thc compositionnl analysis. Evnluntion of both fiact~~scd nnd cut surlhccs proviticd thc
niorpiiologicaI 2nd bonding inib~.malion that was rclatcd to mccllanical pcrlbrmance
obtained from flexural tests. It was concluded that (i) sisal and Eucalyptus grandis pulps
showed satisfactory bonding to the cementing matrix, with fibre-pullout predominating;
(ii) banana pulp reinforced composites exhibited fibre fracture as the main failure
mcclin~~is~~i; (iii) pal-tial fibre dc-bonding and 17latl.i~ niicso-cracking wcsc found to
dominatc at [he intcrlilccs ofanalyscd compositcs.

Toledo Filho and others [303] have given a comprehensive chronological development of
sisal fibre reinforced, cement-based matrices, supported by experimental data to illustrate
the performance of sisal fibre reinforced cement composites, along with a
description on the use of these composite materials as building products.
I

~nvcst~gations how tlie propertics of tlie green sl~ccts can bc rclated to [host of hardcned
products. It is seen that both the above green sheet properties relate directly to the strength
of hardened sheet.
Coutts [302] received and reported some of the Australian research that was carriedout to
establish natural fibres as a suitable reinforcement for cement products. The spread of
Australian ~ood fib1.c ccnicnt technology and the rangc of applications for which thc
natural fibrcs arc used, were discussed and presented, particularly with reference to USA
and Asian activities.
Aziz and others [307] have presented on overview of strength properties, physical
perfor~nance and durability of various natural fibre reinforced concrete building products.
C'ois, siszrl, bt~gassc, julc, bamboo fibrcs bnsccl co~nposilc~wcsc rcvicwcci ~u~cl prcscntccl I(
has been stated that roofing sheets, boards, wall panels (both for partition 1 acoustics)
based on the above composites are in use in countries like Australia in some African
countries, India, Indonesia, Philippines, Thailand, Bangladesh, including conventional and
special applications (earthquake resistant construction).
Do and others [308] have highlighted the process of research and developil~ent of natural
fibre composite materials as well as opinions drawn from the production and application
of the above materials, in Vietnam.Tiles, sheets made of coir, sisal, jute fibres
(withiwithout matrix modification) were compared with imported products in terms of
economic value. Water tanks and filter water tanks prefabricated with their walls have also
been produced with the composites. It has been concluded that natural fibre cement
composites and products have been easily accepted in Vietnam, due to the use of local raw
materials and local labour on intensive scale.
Satyanarayana & others [4] have highlighted the systematic work so far carriedout on the
structure property relationship of jute, coir, sisal fibres, including fracturing modes.
Attcmpts lo incorporate them in polymers and charactcrizalion of tlicsc new co~~ipo~ile~,
with I without subjecting them to environmental conditions have also been reported.
Problems arising out of processing of the composites and attempts made to minimize these
problems have also been described.
Few components fabricated and their performance
have also been highlighted. Suggestions for future work were given, which include;
developing processes to obtain natural fibres in the required form; process to minimize
degradation of con~posite materials and fire hazard; evaluatio~l of various properties.

A/I/ and others [304] have sun-umar~-/.ed the developments upto 1980s the use of natural
librcs l~he co~r, s~sal, sugarcane hagassc, bamboo, jute, wood akwara, plantain , musamba
for making concrete alomg with the various factors which generally affect the wet /
hardened states of concrete. They have emphasised the need for evolving standard test
procedures, design procedures, identification of problems or components were the special
chai;~c~c~lst~cs oi' thc above concrete can be used and thc need for preparing a full
iilnct~onal spec~ficat~on fbr each typc of libre and for a particular application.
Navin Chand [6] presented a review of the work on the structure and properties of some
natural lingo - cellulosic fibres, including uses of these fibres. Micro - structure of fibres
reviewed include; sunhemp, bamboo, ramie, banana, sabai; whereas, properties of fibres
~nclude: sunhemp, sisal, coir, pineapple, ramie, palm, mesta (kenaf), banana, sabai, jute.
lJscs of sunhemp, sisal, bamboo, coir, pineapple, ramic, palm,tucsta (kenaf), eichornia,
banana, sabai, have been highlighted.
Kulkarni & others [309] studied the stress - strain curve, initial modulus (YM) ultimate
tensile strength (UTS), and percentage elongation, as a function of fibre diameter, test
length and speed of testing, of banana fibres. It is found that (i) YM, UTS and
'XI elongation show little variation in their values for fibres of diameter ranging from 50 to
25Opm; (ii) UTS and breaking strain are found to decrease with an increase in the test
length while both breaking strength and breaking strain remain constant with the increase
of speed of testing from 0.5 to 100 x
m and thereafter they both decrease; (iii) the
fibres appear to fail by localized deformation followed by pull -out of microfibrils
accompanied by tcaring ol'czll walls; the mechanism is niorc perceptible at lower speeds
of testing.
Kulkami and others [3 101 studied the mechanical behaviour of coir fibres under tensile
load. Stress- strain curves, initial modulus, strength and percentage elongation of coir
fibres were cvaluated as functions of retting trcatrnent, fibre diameter, gauge length and
stlain rate I[ IS obscrved that (i) no difl'crcnccs [>ctween rcltcd / unrctted; (ii) strcnyth and
percentage elongation seem to increase for both retted / unretted fibres, upto a fibre
diameter of 0.2~10'~ m, thereafter they remain constant; (iii) moduli decreases with
increase in fibre diameter; (iv) failure of the fibre is due to the fracture of the cells
themselves accompanied by the uncoiling of microfibrills ; (v) there is no appreciable
variation in strength and percentage elongation with strain rates for any one diameter of
the fibre ;(iv) with increase in gauge length , a decrease in both strength and percentage

elongation at break has been observed. which have been attributed to an increase of
jxoh:~bility ol' dcltcts and localiscd dcfi)r~~lation and gcntlc necking , respcctivcly.
Sotyanarayana and others [31 11 examined fibres froin different structural parts of the
coconut palm tress (cocos nucofirn , linn.) for properties, such as, size, density, electrical
resistivity, UTS initial modulus and percentage elongation, stress-strain diagrams, fracture
mode, microfibrillar angel, as well as cellulose and lignin contents of these fibres,. It has
bccn concluded that (i)
thc major chcrnical constituents of thcsc fihrcs arc Sound to be
cclliilose (39-46'%1) and lignin (13-25'%), (ii) initial modulus and strength of the fibres
seems to be mainly depend on the micro fibrillar angel and the content of a- cellulose in
the fibres;
McLanghlin and Tait [312] presented the best common physical description of the
mccl~an~sni oi' l'ailul-c in tension of cellulose based librcs A correlation was obscrved
between the mean tensile strengths and young's modulus of fibres extracted from leaves,
stems and other miscellaneous sources, which is attributed to increases in Young's
modulus and tensile strength with decreasing mocrofibril angle and increasing cellulose
content. The importance of cellulose content for strength is not reflected in terms of mean
fracture strain, which increases by increase in mocrofibril angle and resporlsible for higher
\YOI.~\S 01'
~'SI~C(LISC li.o~ii di l'li'rc11~ S~>CC~CS
Mai and Hakeen [313] investigated the slow crack - growth characteristics of both
bleached and unbleached fibre cements. Cellulose fibre cement composites as supplied by
a private company (5mm thick sheets) and both bleached and unbleached cellulose fibres
were considered. Fracture experin~ents were conducted on double-cantilever beam (DCB)
spccimcns. It is hnnd that blcachcd fibres are unravelling than unbleached fibres.
Beaudoin [3 141 has reviewed (in Chapter 8) and summarised the current information
(i.e. before 1990) the research data on strength properties and fracture toughness of current
systems (paste, mortars and concrete) reinforced with natural organic fibres and minerals.
It has been stated that the role of the above material in resisting cracking and impact
loading and improving ductility and energy absorption is of considerable practical
importance and thus the long-term durability of these materials has yet to be established,
i.e. at that point in time.
Schilderman [315] has summarised the role of ITDG (Intermediate Technology
Development Group) in the research, development and dissemination of fibre concrete

oofing (fcr) in the form of sheets and tiles. It has been stated that there is need for proper
dissemination of the technology and approach from early stages, based on the surveys
conducted and lessons learned from Kenya and Peru.
Cabrcra and Nwaubnni 13 161 based on rcvicw of mcthods of cstractioli of oil, total and
alkali soluble carbohydrates and in general, the preparation of palm fruit fibres, grass, cane
sugar and maize fibres, have suggested a tentative set of requirements for acceptance of
these natural fibres for use in cement composites. Based on the study, it has been
preliminarily suggested that glucose = 0.25% and starch = 0.125% (% based on cement
LS~CI~~[) ;is liliiits 10 i1~01il re[;~rd;~:ioll oSccmcnt hydrat~on 11 has also hccn rccognizcd and
~ccon~nicndcd that simple methods of' dcterminetlon 01'
of fibre - cement composites, be carriedout in hture.
lime soluble sugars and durability
Soroushian and Marikunte [317] have presented the results of a con~prehensive
experimental study concerned with effects of moisture content on flexural performance
~h~~ri~c(cr~s~ics
01' wood (il31.c rcinl~~rccd CCIIICII~. Tl~c CCIIICII( co~iiposi(cs COIIS~~CI-C~ wcrc
mechanical pulps (with 1-2% of fibres) under three moisture conditions (oven -dried;
air -dried and saturated). Fresh properties of composites (flow; air content and setting
time) and flexural test (according to Japanese code) were carriedout. It has been concluded
that (i) there is a tendency in flexural strengths to decrease, and in flexural toughness to
increase with increasing moisture content of' the co~nposite; (ii) high moisture contents
tend to damage the fibre - to - matrix bond strength, leading to changes in failure
mechanisms.
Tegola and On~bres [3181 analysed the advantages of vegetable fibres with regard to the
limit state, particularly, with regard to crack - width. Analytical expressions for moment of
first - crack (mPr), distance between cracks (1 ,,,,, , 1 , ), crack - width (w ,,,,,, ),
moment - curvature relationships were derived. Numerical analysis was carryout relative
to reinforced concrete beams with rectangular cross - section in flexure, in order to
evaluate the influence of vegetable fibres on the limit state of crack-width, It has been
concluded, among other things, the effect of vegetable fibres is virtually the same as that
of metallic fibres, especially, for low quanitities of Vr.
A1 Moliamadi [3 191 studied the effect of reed as reinforcement on thc bchaviour of trial
embankment. The field and analytical study has shown that the reed bundles were
effective in reducing lateral strain and hence reducing construction settlement by about

14% The results of finite elenlent analysis have shown that using reed reinforcement is
equivalent to increasing the stiffness of soil by 15%.
A!- Refeai [320] used reed fibres as reinforcement for dune sand and conducted a series of
trail tests The ~nfluence of various fibre charactenstics on the bchaviour of fibre
ic~nfi>rccd sand were investlgatcd 'l'he results ind~cate that the presence of fibres could
lead to a significant increase in ultimate strength and stiffness of reinforced sand. It is
found that increasing the aspect ratio increased the ultimate strength and the stiffness of
reinforced sand. and that the strength is generally proportional to fibre concentration upto
some lirn~ting content
C'oiill\ 132 1 ] l ~ p~cscnlcci s ~ks ovcrvlcu 01' thc way librcs, der ~vcd Piom plants, have been
used to reinforce cement - based products, highlighting the properties of natural fibre
reinforced cements, uses and possible future trends. It is staled that the future of sheet and
roofing fibre cement products must be natural plant fibre reinforcement and that countries
like South Amer~ca and India slio~~ld utilise the wealth of natural fibres available in their
country MOICO\IC~, cmpliasis should bc laid on bcttcr production methods of fibres,
Including novel methods of pulping.
Savastano and Agopyan [322] studied the transition zones of cement composites without
librcs and with fibres (coir, sisal or malva). The effect of the above fibres, wlc ratios (0.30
- 0 46) and age of the coniposite (upto 180 days) on the zone characteristics were analysed
and conlparcd \villi Ilic ~ncclianicnl properties (bending test t~ndcr li~ur - point loading) ol'
the composite. It is stated that (i)
the transition zone thickness is higher than
non - absorbent fibres like steel; (ii) by altering the casting process to reduce the shrinkage
of matrix and hence the micro - cracking of porous region i.e. transition zone; (iii) the
thickness of the region, taking porosity as an indicator, is 50 micrometers.
Ncclamegaln 1323 1
has prescnlcd a brief review of tlic properties and performance of
different types of fibres (steel, glass, carbon, polymer and natural fibres), PC composites,
and FR - PC (fibre reinforced - polymer concrete) composites, including their potential
applications.
Lola 13241 has presented the findings of appraisal steady carriedout on the impact of
rcscarcli ~~ro.jw~ts linanccd by A'I'I (Appropriate 'I'cchnology International) and SCI: (Save
the Children Federation) on FRC roofing sheets as a low cost roofing alternative during
early 1980s. After reviewing over 10,000 roofing sheet sites during the above period, it

has bccn rccon~rnended that (I) the production process of roofing sheets be standardised;
(ii) further research to study the effect of alkalinity of cement in tropical environment, to
develop geometrical shapes for sheets which minimize the risk of damage during
production and installation.
r>clvasto and others [325] made n cornpnrativc study of the pull-out behaviour of fique
lihrcs (:I coniti~cscially ava~lnlic nalurni fibre in Columbin) in mortars of' I'ortland cemcnt
and compared to the bond behaviour of steel and glass fibres embedded in the same type
of cementitious matrices. Pull-out tests were carried out using 'figure-eight' specimens'
prepared using different wlc and cis (cement /sand) ratios. The critical length, shear bond
nlodulus of thc matrix at thc intcrfacc. tlic adlicsionnl bond strength and the frictional
sllca~ I,onil .;[tciig[li 01'
[lie t1.1ci1 lil~rch. wcrc dctcs~iitncd I t is concluilcd [hat (i) stccl
libres showed the best results of adherence when the wic and c/s were higher;
(ii) mortars with 'fique fibers' reported a pullout behaviour similar to that of other natural
fibres; (iii) stcel and fiber co~nposites did not suffer catastrophic bond failure afier the
maximum pull-out load had been reached because of the higher bond of the steel fibers
wit11 llic 111atl.i~ than [liar of' other 'liqiie' fiber rcitili>rccd samples; (iv) glass fibers
rcinfi>rccii spccinicns Sailed without debonding of thc fiber.
Silva and others [326] studied the mechanical properties of the transition zone between the
fibres and cement paste, considering the mcchanical properties of the composites
constituents. Cementitious composites reinforced with bamboo, eucalyptus and sisal pulps
beside the wollastonitc fibers were studied. Natschek method was used for the production
using fiber mass fraction of 8% and 14% for the pulps and for the mineral fiber
'wollastonite'. Static and dynamic tests on appropriate test specimens were carriedout on
the developed composites. Behaviour of fiber-matrix interface at microscopic level were
studied by SEM. Based on the available semi- empirical formulae, which have been
ajusted to the obtaincd experimental results of each composite, tlie iiitcrfacial bond has
becn rclalcd [o the ioughncss of the ccmcntitious coniposites reinlbrced with vegetable
and wallastonite fibres. It has been concluded that (i) wollastonite has the highest fiber-
matrix bond stress among the fibres used and that such a high bond stress didn't contribute
for its toughness due its very small length (50 - 100pm); (ii) the higher fiber-matrix bond
stress exhibited by vegetables fibres (highest by sisal) has contributed lo the higher
touglincss ol'thc composites.

I3ilba and others 132'71 studied three pre-treatments for two fibres ( banana trunk, sugar
c,lnc bagasse!, pyrolysis, basic Cii(O!l): and acid t I 2S0.1 attacks and study thc effect of
111c paralileters, namely, fibre content, chen~cal treatment, aging of' composites, initial
botanical composition of fibres, on the thermal properties of vegetable fibres 1 cement
con~posites . It is found that (i) a decrease of thermal conductivity when the amount of
fibres increases, after 30 days of hydration; (2) better insulating performances of
composites prepared with heat -treated or chemicaiiy- treatcd fibres.
I

toughness ind~ces given in the codcs of practice, such as, ASTM C- 1018 (1989), JCI -
SF4 (1983). JSCE -Sf4 (19841, ACI 544 (1987). can be used to obtain information on the
ij~i'\!~t

uhcre, s,b.d are the span, breadth and depth of the specimen; dl - specified deflection and
I - area under the load - deflection curve upto the deflection ' dl'.
(C) lVord N ~ (1 I Id i ,%.let 11 od
1 h~ce new tlexural toughness ~ndlces (T,,,,, , T$(, and Tie ) that reflect the general shape of
the load - deflection curve, were proposed by Ward and Li. 'T,,,' is defined as the beam
deflection at maximum load divided by the deflection at first crack and is somewhat
analogous to the 'ductility ratio' used with reinforced concrete beams. The above index
gives an idea of the 'inelast~c deformation' and ' multiple cracking' that occurs before the
t~lr~rnarc load is rcaclied. ' 1 T,,'
IS dclined as ~ hc dellcci~on when load drops to 50% of'the
maximum value divided by the deilection, which would be observed at a sim~iar load on
the ascending part of the load - deflection, if the beam behaved linearly - elastic, up to
this point. It reflects the ability of a beam to absorb energy by 'inelastic deformation'
relative to the rate at which it strores or releases elastic energy. 'Tlo' is defined as the total
,i~cu undc~ ~hc loi~cl - dcllcct~on cilrvc upto thc point, whcrc, thc load drops lo 10'X ol'thc
maxlmum value, divided by the beam cross - sectional area. It correlates approximately to
the total energy- absorption capacity of the beam.
2.6.4 Importance of Flexural Toguhness for Natural Fibre Composites
In the case oS natul.al librc cornpositcs, evaluation of Ilcxu~~al toughness (1'1')
has a spccial
significance. Durability of the composite as such and the relative improvement in the
durability of the composite (due to various methods of enhancing I improving durability)
are evaluated based on 'FT' of the natural fibre composite.
2.6.5 Ovcrvicw of Studics
Reported literature so far, on studies pertaining to flexural toughness of various
composites, were comprehensively reviewed to identify the evaluation methodology and
purpose for various systems (cement 1 cementitious composites etc.), which are
summarized in Table 2.10.

Table 2.10 : Over view of Evaluation of Flexural Toughness of Cement I Cementitious Systems
S1. Author/(s) Year System considered
No.
1. Bentur, A 1987 GFRC composites
Evaluation methodology
I Purpose ' (s)
-Work of fracture (WOF) of the .Durability of composite (i.e. GFRC) 330
composite, as determined by the due to incorporation of SF was evaluated
area under the load-deflection / in terms of WOF and MOR. I
curve upto the deflection under
the load-deflection curve at
which the load has fallen to 75%
of its max. value.
*The above is taken as a measure
of 'toughness --- of composite'.
-
-Toughness index (I*) is defined
as the area under the loaddeflection
curve for the fibre
reinforced specimens divided by
the corresponding area for plain
mortar specimens.
-The above definition is different
from that used in ASTM, due to
the difficulty in determining the
on set of first crack in SIFCON
(slurry- infiltrated fibre
concrete).
-
which is one of the
systems considered.
A saw-cut notch was made in
the flexural specimens (76 x 304
x 38mm), lvhere the notch- to -
depth ratio was maintained to
one-third.
To evaluate the durability of four types
of fibre reinforced cement composites:
conventional steel, polypropylene, glass
fibre reinforced mortar and SIFCON.
Composites exposed to intermittent
drying and wetting in a 3.5% NaCI
solutio11.
*To obtain durability of above in a
corrosive environment so as to obtain a
rational design.
.'To evaluate thc long-ten11 properties of
cellulose fibre reinforced con~posite.
under two types of accelerated aging
methods, namely,(i) hot-water soak and
(ii) repeated wetldry ageing. --
... Contd.

S1.
No. -
Marikunte, S
Soroushian, P.
Year System considered
Cellulose fibre
reinforced cement
composites.
5. Malhotra, V.M. 1994 Polypropylene fibre
Carette, G.G.
reinforced high-volume
Bilodeau, A.
fly ash concrete
Evaluation methodology
*Toughness is measured as the
area underneath the load Vs
crack-mouth
opening
displacement (CMOD) curve.
* Plexural deflections were
recorded by performing flexural
tests according JCSE-SF4 [FT-
201.
*Area under the load-deflection
curve used to determine 'flexural
toughness'.
0 102 x 102 x 381 mm prisrns
were used to determine flexural
toughness of concrete by AS7-M
C 1018 test.
.The area under the loaddeflection
curves after the first
crack was calculated in such a
manner to give a conservative
estimate of the values of the
indices (Ij, Ito, and 13,,)
*The above indices correspond to
linear-elastic material behav~our
up to the first crack.
~Indcx ratios, such as , 110 / Ij and
13" / 110 were also used to evaluatc
toughness perfornxince.
Purpose / (s)
*As cellulose fibres are less expensive.
their use merits evaluation over polypropylene
fibre reinforced concrete and
use it for crack control in concrtes.
,Long -term durability of cellulose fibre
reinforced cement composites, subjected
to accelerated \\.setting-drying and hotwater
soaking conditions, were
investigated.
eConclusions denved are sought to be
used in the design of cellulose fibrecontent
products 11ke their-sheets.
ePolypropylenc fibre reinforced h~ghvolume
flyash concrete for shotcretins
applications 1.e for rock outcrops mas
investigated.
The desirable level of fibre in the 1
Ref.
/ No. 1
I
i
... Contd.

Bar, B.
Asghari, A.
Hughes, T.G.
Ward, R. J.
Li, V.C.
- -
Souroushian, P.
Aouadi, F.
Nagi, M.
Year
1988
1990
System considered
I Evaluation methodology
Polypropylene and steel 0 A special type of test specimen
fibre reinforced geometry, used for shear strengtll
concrete. 1 of concrete and a loadinp -
arrangement to investigate shear
failure was used.
*Load- deflection curve obtained
from tensile tests were used to
define two types of toughness
index as defined by Ban et.al
[FT-71 and Johnston [FT-81.
load- deflection curves
(Steel, Aramid and were obtained for mortar
Arylic highpolyethylene)
* 15, 110. and 130 indexes as
defined by Johnston [FT-81 were
calculated.
0 Three nen flexural toughless
indices ('T~nax, and TI0 )
defined.
I e A new simpler estimate of
flexural tou-hess in the form of
ff / ft ratio and Tmax, Tlo derived.
The
-
usefulness of method
illustrated.
-. . .-
Latex-modified carbon 38 x 38 s 152mm specime~ls
fibre reinforced mortar. for 4- pt. loading on a span of
114rnnl used for flexure.
/ - Flexuraltough~ess was defined
-- - -. -
Purpose / (s)
-- -
8 1'0 evaluate the tensile strength and
post-cracking performance of plain
concrete and FRC composites (using
steel and polypropyiene).
0.4 simple compact tenslon test specimen
geometry proposed for the above
purpose.
To demonstrate the usefulness of a
simple procedure for sstlmating material
brittleness, and that car1 be used in
design a d qualit! control applications.
1'0 extend the research based on this
study to practical concrete and fibre
concrete mixes.
perfori~~ance characteristics of carboll
fib~e reinforced mortars incorporatirlg
sllica fume were ~n\estigated.
---
Ref.
No.
334 -
I 336

~
Banthia, N.
Gupta, P.
Yan. C.
13. Banthia , N.
Dubey , A.
1999
. --
Fibre -reinforced wet -
mix shotcrete (steel ,
polypropylene, carobon,
poly-vinyl alcohol -
PVA)
1;ibre reinforced
concrete (steel and
polymeric)
--
Evaluation mcthodolok~
--
of fibre reinforccd concrete-(in
MPa, f ti~ncs 0.015.
e The above two values are
compared using experimental
and predicted equation.
e 100 x 100 x 350nim beam
specimens, under four- point
loading, span = 30mm as per
ASTM C I01 8 - 96. (static test)
0 Howcvcr, flexural touglmess
factors (FI') as recornmended by
JSCE in their standard SF-4 [FT-
201 were calculated to a midspan
displacement of 2mm.
vote: (*) - JSCE ' Method of
test for flexural strength and
flexural toughness of fibre
reinforced concrete- standard
JSCE - SF 4', JSCE Std. for Test
Methods of FRC, 1984, pp.45-
511
.A new ASTM techruque
residual strength test method
(RSTM), was used.
.A stable narrow crack is first
created in the specimen by
applying a flexural load in
parallel with a steel plate, under
controlled conditions. The plate
parameters
-.- -. -
- --
o To exan~inc the behaviour of fibre
reinforced shotcrete under impact loads
caused by blasting or rock bursts. so as
to use shotcreting to minimize rockburst
da~uage and to enhance tlze safety of
mine markers.
e To compare the two methods
a To apply to steel or synthetic fibres
(polymeric) with low fibre volurne
fractions and to obtain reliable post-peak
load response.
-- -
Ref.
No. -
I
. . . Contd.

System considcrcd
F~bre reinforced
concrete (stccl,
Polypropylene, PVA
and nylon including
hybnd fibres 1.e. steel
and polypropylene)
F~hre reinforced
concrete
-- - . - - - - - - - .-.
in then removed ano ll;r
co~iducted in a routlne manncr
I
. --
Iicf.
No. -
Newly introduced 1 approved cons~sting of seven different 343
(fivc ~~llcrodcnier and
wcrc irivest~gatcd. -
obtaining Av. Resldual strength *Other set eight commerc~ally available
of FRC).
niacro fibres (largc d~ameter ) (5 pp;
steel, 1 PVA) investgated
.To validate KS 1 M and generate data
base for different fibres R: volume
fractions
RS 1 M effecttve highly ell-ective in
different~ating between vanoils d~fl'crent
fibres types, lengths, configurations.
volume fractions. gcolnetrics -
and
moduli
- __-
reviewed.
interpretation of load-deflection
relationship for evaluating
flexural toughness identified.
.A new system of measuring
touglmess, comprising a series of
indices based on overall
behaviour up to specified
multiples of first-crack
cval~iate toughless and to iclentifv
approp~~ate provisions for inclusioll 111
AS'PM standards.

Si.
No. -
Author/(s) I Year I System considered I Evaluation methodology I Purpose / (s) I lief.
--
Taylor,M.R.
Lydon, F.D.
Rarr,R.I.G.
Bindiganavile, V.
Banthia,N.
Ramalingan,N.
Pararnasivam,P
Mansur, M.A.
Maalej,M.
1996
2001
FRC
(steel, polypropylene)
FRC (polyolefin pol~
propylenc, steel)
Hybrid fibre -
reinforced cement
composites containing
hi& -volume flyash. (
PVA micro - fibres,
PVA fibres and steel
fibres)
--
deflection, .- pgosed.
.Toughness measurcrncnts *To obtain better mcthods of
carriedout tho' two fracture- tougtmess measurements and hcncc
type test specimens on notched
specimens:
toughness indices, suitable for a range of-
~lormal to high- strength concrete mixes
(i) notched beam; (11) notched with fibres.
cube
*Notched beam test was based on
RlLEM draft recommendations
1985 [ FT-I71
*Notched cube test was based on
earlier work of Barr and others
[FT-71.
~Test conducted
1018-99.
*Analysis of load-deflection variable stain rate and to determine their
curves followed the flexural toughness characteristics.
recommendations of JSCE- SF4
procedure
.ASTM C 1018
get toughness indices
using diffcrcnt conlbinations of fibres so
*Flexure tests under third pillt as to exhibit strain - hardening
loading were conducted
behaviour untler flexural loading.
*Volume- fractions of hybrid fibres ,
W/B ratio and % replacenlent of cenle~lt
by flyash wcre optimized to achieve
strain - hardening behaviour with
multiple cracking.
I

Year System considered
steel fibrs.
Evaluation methodology
o'foughness indices and residual
strength factors were calculated
as per ASTM C 1018 for flat-end
hooked - end steel fibres.
*Flexural toughness factors
calculated as per JSCE SF4
procedure.
---- --
Purpose / (s) 7x2: - - :
e.1'0 study the effective~less of four
mineral admixtures (flyash, silica fume,
high - reactivity metakaolin and carbon
black) with varying particle size.
gradations and shapes, on rebound of
sholcrete.
eTo compare HRM and SF on the basis
of hardened mechanical properties with
emphasis 011 flexural toughness in the
presence of fibre (steel) reinforcement.
-- -. -
1 No. 1
349
1
I
i
-.. - -.- - .
1
I

Based on the con~prehensive review of reported literature on the characteristics and
durability aild on the various st~idies carried ut on sisal fibres !cement composites, and
i;
bused on the csitical analysis of Lhc abovc, fbliowing observations are made;
(i)
(ii)
Characterization of sisal fibres has been comprehensively carriedout and the
~~ieclianisms responsible for its deterioration in an alkaline environment has
been fairly understood. However, quantative siudies on the effect of alkaline
cnvironn~ent on the chcn~ical composition of natural vegetable fibres, in
gcncral, is rarc.
The effective way to enhance durability of natural fibre cement composites has
been established by now. However, studies on the use of certain pouolanic
material like flyash, in natural fibre cementitious composites, like that of sisal
or coir, is in general, rather rare.
(i~i) Dcvclopincnt of [cst!(s) cxclusivcly for dctcrmining thc wct state
(iv)
(v)
characteristics of natural fibre cement/ cementitious composites, is found
necessary. Moreover, development of tests to understand the rheological
behaviour of natural fibre composites has to be initiated and standardized. Due
to the lack of the above, there is no standard accepted mix design approach,
considering thc rciluircmcnts of'workability, durability and strength, for such
composites.
Strength behaviour of natural fibre composites have been extensively
investigated. However, studies on shrinkage characteristics, transition zone,
fracture toughness, are not that very exhaustive, especially, for cementitious
composites.
Natural fibrc bascd roofing materials have been studied extensively and
products developed. However, the full potential of natural fibre cementitious
composites have not exploited for developing comprehensive range of
products, for use in buildings 'i Civil Engineering applications.
From the above, it can be stated that there is sufficient scope for the present investigations
with the stated objectives as in Chapter 1, and with a view to address a few identified gaps
in the area of natural fibre cementitious composites, i.e., in the behaviour of such
composites in the wet and hardened states.

CHAPTER 3
1SXIPI

phosphogypsurn; agricul:ural wastes such as rice husk ash (RHA), rice straw ash (RSA),
coco~iut htisl\ ash (C'llA), corn cob ash (CC'A), pcanut shcil ash (PSA), sugar cane bagasse
ash (S13A), ~nc~iicitttcd munlcipai sol~d wastc ash (MSWA); natural po//.olnnas (Nl'ss), such
as, volcanic ash, pumice, diatomite and scoria powders; chemical wastes containing minerals
such as, refined boron gypsum (BG), colomanite ore waste (CW), tineal ore waste (TW), red
mud from alum producing plants, havc so far been used in ccment systems and their influence
on various characteristics investigated.
Ilsc ol' Ilbo~c ~lli~(~i.iill\ [IS C'IIMs ~11.c i~iipoi.t:~nt f'rom cco~ioniy, ~cology and engineering
persepectives. It is well known by now, that different CIbVs will have different effects on the
properties of the cement system considered, which are pri~uarily due to thcir physical,
chemical and mineralogical characteristics, and to some extent on the 'curing regimes' and
'ages' considered. Hence, the choice of a 'pozzolana' depends on the purpose and availability
ol'a palt~ciii,~~ (~'1st~) rnatc~ la1 in siilliclcn~ iluantitics ni~ci at itSSordablc cost
In the present study, flyash has been selected as the pozzo!ana for use in cementitious system
due to easy availability, lower cost and for the reason that it can lower the alkalinity of the
matrix - a fact which needs to be exploited to ensure the durability of sisal fibre composites
considered in the present study.
(U) Source
Flyash from the nearest thermal power plant of Neyveli Lignite Corporation (NLC) at
Neyveli (located about 80 km from Pondicherry), Tamilnadu, India, was collected and used
in the present study. The lignite mine located and in operation till date, at Neyveli, is the first
and only of its kind with the largest deposits of lignite, in India. There are two thermal power
slalions currently in operation In thc above plant, wherc, Ilyash is collcclcd by clcclro-static
precipitators (ESPs). At present, most of the flyash is supplied directly to 'bulk consumers' of
various cement industries. For the present study, flyash was directly procured from Neyveli
Thermal Power Station (NTPS) as a single lot, stored and used for the various experimental
investigations. The above flyash is from the 'lignite' source. The properties of raw lignite -
the source for the ash in this study, are given in Tablc 3.2 [352].1'he above propertlcs are
based on a study carriedout and reported by the NLC authorities.
(C) Physical and Chemical Characteristics
Salient physical properties of flyash like specific gravity, fineness, particle size distribution,
setting time, compressive strength were determined adopting various Indian standard

procedures and the results obtained are given in Table 3.3. All the tests to determine the
clicniicnl compoqltio~i of tlic !lynsh sampic (as reportcd in this study), were carriedout at the
'C'cnlrc 1'01 Apl,llcii licscaicil 'irid l)cvclopmc~l~' (C',AI), a r.cscarch and dcvclopmcnl
centre, having sophisticated equipment for analytical and testing purposes, and a unit of NLC.
The results of the above tests, as furnished by the NLC authorities are presented in Table 3.4.
Apart from silica, alumina, and various ol1ler oxides, flyash (in general) may contain some
highly toxic metals (for e.g. molybdenum -Mb5 mercury (Wg), selenium (Se), cadmium (Cd)
In tracc c~u:uititicc, say 1
mg lo 100 mg / kg of ash) llowcver, in this study detcrniination and
discussion 1s restricted to only the major chemical composition of flyash.
The maximum residue (in % retained) on a 45pm sieve, as specified in various international
standards, the chemical requirements for flyashes in different countries, the compositional
ranges of flyash from different countries and classification of flyashes based on oxide
conlpositloii (according to Ilrocjc, S and as reportcd by Wcsche [353]) arc given in Appendix
A-3 to A-6, respectively.
(D) Discussion on tlre Plysical Cltaracferistics of Flyaslt
(1) Specific Gravity
Thc specific gravity of the flyash used in the present study is slightly higher than the range of
vnlucs ~cporlcd by Shnrma [354], which was based on 25 samplcs of various (i.c. coal-bascd )
Indian flyashes and it is less than the maximum value i.e.2.98 for an iron-rich bituminous ash,
as reported by Wesche [353] and Malhotra and Ramezanionpour [355].
(2) Partile Size Distribution
Wet sieve analysis fallowed by hydrometer analysis were carriedout as per the relevant
IS codes on tlic sa~nplc ol' flyash to ~~ndcrstnnd its particlc six dislribution. '1 hc rcsults or tlic
above analysis are presented in Table 3.5.
Flyash particles predominantly range from 150 pm to finer than 10 pm. More than 80% are
finer than 75 pm and 65-75% finer than 45 pm. There is significant quantity of particles
below 20 pm to 10 pm. The presence of particles below 45pm and more specifically below
10 and 20pm, are expected to contribute to the pozzolanic effect and enhancement in
compressive strength [356, 3571. The categorization of Indian flyashes based on particle size
below 1 Opm, as reported by Sharma [354], is given in Appendix A-7.
The flyash sample in the present study falls under category P3 (i.e., particle below 10 pm are
in the range of 20-35%), based on the categorization of the amount of particle (%) below

i 0 ~LIII, for the Indian flyashes, as reported by Shalma [354]. It is to be noted that the above
observation is in contrast with the corresponding values reported by Mehta for US flyashes,
wherein thc particles below 10 pm were 38-5096 [3541. Even though the maximum residue
(I c '% SCL~L~~~LICI) 011 351~111 S~CVC is 1101 spccilicd in he Indian codc, various International
codes have such a stipulation, which ranges from 12.5 (in UK standard) to as high as 50%
(in Germany and Australian standard).The flyash sample in this study satisfies the above
International stipulation. A comparison between the particle size distribution of 25 samples of
flyashes located in different parts of India, produced from the combustion of bituminous or
sub-bituin~nouc coals and considered to be oi' low-calciiim content and iised for the
invest~gations by Shanna [354],with that of the flyasii sainple cons~dered in this study, are
given in Table 3.6. It can be seen that the particle size distribution of the flyash studied
generally has the same trend and that it is coarser than other Indian flyashes, as investigated
and reported by Sharma [354].
(3 1 Fineness of' Flyash
'Fineness' is quantified by the 'specific surface' of a material. The 'specific surface' is
defined as the 'number of units of surface area' contained in a 'unit weight' of a material. The
specific surface or 'fineness of flyash' (as determine by the Blaine's method) generally varies
from 250 to 550n12 /kg (i.e. 2500 to 5500 cm2/g) [353]. The most commonly used method to
determine the specific surface area, is the Blaine's n~ethod, which is based on the resistance
offered by the pulverized materials to an air flow. Particle-size analysis can also be used for
the determination of the specific surface area of flyash; a laser particle - size analyzer is
usually used for the measurement. Another method of determining specific surface is the
BET technique (Brunaur- Emmet - Teller technique), in which nitrogen adsorption isotherms
arc nleas~ired. I-Iowevcr, data obtaincd by this method
dirfer from those of' the Blaine's
method and that 3 to 4 times greater than the Blaine's values have been noted, even for
ordinary flyashes, because, 'BET technique' measures the 'totality of voids existing in the
surface' of particles. A study of granulometric curves also provides an indication of flyash
specific surface. However, values are commonly 30% lower than those obtained from
Blaine's method, as not all flyash particles are spherical in shape [353, 3551.
In this study, the fineness of flyash was determined by Blaine's air permeability method as
per IS: 1727 [358]. The results of the above test are presented in Table 3.7. It is observed that
the fineness of the flyash sample used satisfies the minimum requirement as specified in
IS: 3812 [359]. The fineness of the flyash sample used is observed to be in the range of

fincness values (1.e.400 - 450m2/kg) as reported by Chopra and others [360] for the Indian
flyashes investigated by them. Moreover, it is also observed that the fineness of the flyash
sa11iple is also within the range of Blaine's fineness values (i.e.341 to 534 m2/kg) as reported
b) Sharn~a 13541. based on 25 samples of Indian flyashes (from coal-based thermal power
plants located mostly in North India). It is expected that the fineness of the flyash sample will
result In 'good pozzolanic activity'
(4) Lime Reactivity of Flyash
Currently, evaluation of 'pozzolanic activity' is classified under three categories, namely,
(I) chemical methods: (ii) r~icchan~ca! methods and (iii) instrumental methodsltechniques.
Many investigators have attempted to devise simple chel~lical methods to evaluate the
pozzolanic activity of flyashes, as these would consume less time than pozzolanic activity
tests based on strength development. However, no single method has been definitely
established. Most researchers agree that it is not yet possible to predict the reactivity or
po~~olan~c activity from any known combination of physical and chcmical mcasurcmcnts on
flyash alone. The need for rapid methods to evaluate the reactiv~ty of flyashes and the
developments that have taken place in material science have introduced many modern
analytical methods, such as , X-ray diffraction analysis (XRD), differential thermal analysis
(DTA) etc., and most of them result in qualitative analysis. In view of the above limitations,
direct test of strength with lime is still necessary to evalilate the reactivity of flyashes.
In Indian codes, lime reactivity test is specified In IS: 3812-1981 [359], for evaluating
flyashes, and hence adopted in this study. The reactivity of the flyash sample was determined
from 'lime reactivity test' as per IS: 1727 [358] and the average compressive strength based
on three specimens is reported as the 'lime reactivity' in MPa. The result of the above test is
presented in Table 3.7.
Studies carriedout by several investigations on Indian flyashes from several sources have
reported the lime-reactivity values in the range of 33-76kg 1 cm2 (i.e. app. 3.3 - 7.6 MPa)
[361 to 362, 3541. The highest value of lime - reactivity (i.e.76kg/cm2 or 7.6 MPa) has been
reported by Sharma [354]. Based on the lime-reactivity values of Indian flyashes investigated
by him, he has classified them into three groups, namely, 'highly reactive', 'medium reactive'
and 'low reactive'. Details of the above classification are given in Appendix A-10. The lime-
reactivity of flyash used in this study can be classified as 'highly reactive or H-type', based
on the classification proposed by Sharma [354]. The high lime-reactivity values of the flyash
sample can be correlated to the substantial quantity of flyash particles below 45pm and

higher quantity of flyash particles below 20pm. The presence of fine particles in the present
flyash sample. have contributed to the higher pozzoianic activity, confirming the
phenomenon established by several investigators, earlier [356, 354, 363, 364, 357, 361, 3651.
(E) Wiscussiotz 012 the Clzm~ical Cornpositiorl of Flyrrsh
(1) General
It can be seen (I'abie 3.2) that the raw lignite contains nearly 50% moisture and that the ash
content ranges from 3-1 3%, with substantial amounts of volatile matter. These characteristics
arid con~positions of 'raw lignite' are expected to influence the chenlical composition of the
11gli1tc - bascd Ilynsli used in 1111s study
(2) Loss on Ignition
Loss on ignition (LOI) (i e. unburnt carbon present in flyash), is one of the important
parameters for assessing the quality of flyash. Carbon acts as a 'dilutant' of the active
poz7,olanic matter and hence, it is considered as an undesirable constituent. Carbon content in
flyash IS decisive in determining the water requirement for concrete and mortar applications.
It is also an important parameter for classifying flyashes into various groups, namely, group-
A (0-5%), Group - B (5-10%) and Group-C (8-15%), as proposed by Wesche [353]. LO1 of
the flyash reported in this study is much lower than the max. limit (i.e. 12%) prescribed in
IS 3812-1981 [359]. and it is even lower by International standards , which is 3-6% (max.),in
most of the developed countries [353, 3573.
Based on Lo1 content, the flyash sample falls under Group -A, i.e. containing a 'low-range'
of LO1 as proposed by Wesche [353] and under Group-11, i.e, containing a 'low-medium'
range of LOI, based on the study of Indian flyash by Shrama [354]. Due to the lower carbon
it is not expected to affect the strength of concrete [357, 3661. The classification of Indian
flyaslles based on LoI, as reported by Sharma [354], is given in Appendix A-8.
l3) Oxide Composition
Fly ashes are particularly rich in silica (SiOz), alumina (AI2O3), ferric oxide (Fez03) and
Calcium oxide (CaO). They also contain other oxides, such as, magnesium oxide (MgO),
Inanganese oxide (MnO), potassiu~n oxide (KzO), sodium oxide (N20), titanium oxide
(l'iOz), phosphorous penlaoxide (PzOs), sulphur trioxide (SO3) etc., in smaller quantities.
Although the above are reported as oxides, in reality, they occur in flyash as a mixture of

si!icaics, oxides, and sulphates with sinall quantities of phosphates and other compounds, as
reporled by Wesche [353], Se!.ifig and Gibson 13671 and Abemethy & others [368].
Frorn the results of chemical composition given in Table 3.4, it can be seen that the total
oxide content, i.e. sum of the oxides of silica, alumina, and iron are nearly equal to the
minimum value PI-cscribcd (i.c. 70%) i11 the I.S.code. Magnesium content is less than the
maximum limit (LC. 5%) stipulated in 1.S. 2812-1981 13593. Calcium oxide (CaO) is present
in significant quantities. In genera!, the flyash sample used in this study satisfies the
requirements of IS: 3812 [359]. As the CaO content is more than lo%, it is expected to have
both 'cementitious' and 'pozzolanic' properties, based on ASTM C618 - 1985 [369] and as
rcportcd by Wcschc 1353)
Comparing the compositional ranges of flyash in this study with those of the reported
chemical compositional ranges of flyashes of other countries, Indian flyashes, and two
lignite-based U.S. ashes, as reported by Narasimha [366] and reproduced in Appendix- A-9,
it is seen that the silica and alumina contents of flyash considered in this study are
cornparable with those of flyashes from other countries and various flyashes from India.
Ilocvcvcl-, tiic alumina contcnt is slightly lowcr than that rcportcd Sor llyash from othcr
countries and it is higher than the reported alumina content of lignite - based flyash of USA.
Hence, the higher contents of silica and alumina is likely to have a greater influence on the
pozzolanic potential of flyash, as observed by Watt and Thorne [363]; Thorne and Watt [370]
and Cobrera and otliers [364].
Iron oxide of the flyash is substantially lower, say, nearly half of the reported values of Indian
flyashes and that of the other countries. Hence, it is not expected to cause deleterious effect
on the compressive strength of the composite [37!].
CaO content of flyash is much higher than the reported values of Indian flyashes as reported
by Slinrmn 13541 and that of otlics countl.ics Ilowcvcr, 11 is much lowcr than that of thc
rcportcd values of lignite - bascd flyash of USA. I-Iowever, flyashes v~itli a very high contcnt
of CaO are not considered desirable, as they are capable of causing unsoundness in mortars
and concretes [353]. The CaO content present in the sample used in not very high and hence
it is not expected to pose problems when used in cementitious composites. On the other hand,
it is expected to play a positive role due to its 'cementitious' and 'pozzolanic' properties.
Even though the MgO content of the tlyash is slightly higher than the reported values for
Indian fly ashes, it is comparable to the range of reported values of flyash of other countries

all

sample and thc rcsults arc given in Table 3.9 (b). The fineness modulus of the sample used
was 2.50 anii Ihc sample conl'ornis lo ~hc gradation cos~~cspondinl:iiii Lo Lone-11, as s~ipulatccl in
I.S:383-1997 [374], indicating the sample used predominantly contains coarse to medium
sized particles, and doesn't contain too much of finer particles.
3.2.4 Water
Good ijualily po~ublc water availnblc in (lie I'ondichcrry 13nginccring College (PEC) canipus
was used both for mixing and curing specimens. The above quality of water was also used for
conducting various other tests reported in this study.
3.3 SELECTION & PRELIMINARY INVESTIGATIONS ON NATURAL FIBRES
3.3.1 Sclcction ol' N;rtur.:~l liibrcs
Four types of natural fibres which are either locally available or in the nearby regions and in
substantial quantities, namely, sisal, coir, jute and hibiscus cannabinus, were initially selected
and used for the various preliminary investigations. Of the above fibres, sisal and coir are
locally available, whereas, jute and hibiscus cannabinus are available in the nearby regions
i.c. in 'l'amilnadu, Soulh Iniiin. All the abovc librcs arc available in proccsscd wici rcady-lo--
use fon. Fig. 3.1 shows the above fibres from 'as available form' (i.e. plant) to 'ready-to-use
form'. Salient physical properties, chemical composition and mechanical strength of the
above fibres were determined in their natural form (i.e. ready- to-use form). Durability
studies of all the above fibres by exposing them in water, sodium hydroxide and calcium
liydsosidc niccliunis and suljcctinp tlicm to 'continuous immersion' and 'alter~iate wetting
and drying cycles' for a specified period were carried out to ascertain their relative
performance in the above mediums, and then to select the best /desirable natural fibre to be
used as a reinforcement in the matrix. Detailed and comprehensive investigations were
carried out only on the resulting composite (i.e with only one of the selected natural fibres)
and using it either in any one or in both the binders considered in this study.
3.3.2 Physical Properties of Natural Fibres
(A) Length and Diameter
Length of fibres in each family was measured by a Vernier scale and the diameter by the
micrometer (fitted to a microscope normally used to determine the Brine11 Hardness Number
- 131iN in tllc lubolnlo~.y) and h~lving an nccur:cy ol'0.01 m!n. Fifty (50) samples nT librcs

were selected to measure the length and diameter, for each type of natural fibre considered.
OJ7~~1.\alions were made a( several cross sections ofthe rcprcscntativc sample of the fibre and
tlic rangc ol' values of diameter. 'l'ypical observation t~scd Sos tile above, is give11 in
Appendix B-1. The results obtained are given in Table B 1.
(B) Specific Gravity
Density of the fibres were detennined as a ratio of weight to volume using a Pycnometer,
whcrcin, the vol~~nic of disldaccd water can be c;isily ~iic;~s~~rcd. A brief' outlilic of the
psocedure adopted is given below:
(i)
(ii)
The standard bottle was cleaned, dried and weighed along with the stopper (wl).
It was filled with distilled water at room temperature (app, ranging between
27-30' c) and weighed, after drying the outer surface thoroughly (w*),
( i i ~ ) 5 lo 10 gm of the librc (in dry condi~ion) and Icngtli varying from 30-50 mm
was f'illcd rnro dry bottle and weighed (w,)
(iv) The remaining space in the bottle (after filling it up with fibres as stated above)
was with distilled water (at room temperature, closed with stopper and weighed -
wq ,(within five minutes of addition of distilled water).
Specific gravity is generally calculated using the formula given in Eqn (3.1).
S~nce natural libres have a tendency to absorb substantial quantities 01'
waler, cspccially,
within the first hour after they are immersed in water, specific gravity of the natural fibres
used in this study were calculated after 24 hours of immersion in water. Accordingly, the
weight of the bottle with fibres immersed in distilled water was determined at the end of
24 hours of iinmersion, which was denoted as wg, Hence specific gravity of natural fibres was
determined using the formula given in Eqn. (3.2) only, and after 24 hours of immersion of the
fibres in water.
Specific gravity =
(w3 - w1)
[(w2-w1) - (w4-w)l
(w3 - WI)
Specific gravity of natural iibrc
..
=
[(wz-WI)- (wg-w3)]
The above test was repeated for three samples of each type of fibre and the average value
determined, is taken as the representative value of specific gravity of the fibre.

(C) #'liter Absorption
~;lrl,pIcs ol'i1i.y li111.c~ cu[ ill lo Icl~gtlls l.:~nging I,c~wccl~ 50-75 111111. U'CI.C wciglic~I (wi) ~ l d
kept imnlersed in Lvater for a specified period of time. At tlie end of the specified time, the
fibres were taken out of water and weighed (wz). Based on the above, water absorption of
fibres werc determined using Eq~(3.3) and expressed in percentage.
For the first hour of immersion of fibres in water, the weight of the fibres (ie.wz) were
determined at every 10 minutes interval. Afterwards wz of fibres were determined at the end
or2 hrs. 3 hrs. 24 hrs, 48 hrs and 72 hrs of immersion in water. Results ofthe above test for
~IIC I~)LII. liat~~rill libres are shown in Fig.3.2
(D) Tensile Strength of Fibres
Stress-slrain bchaviour ol' fibres were determined by testing them in a 5kN capacity
universal tension testing machine (micro-processor controlled ) with a dedicated automatic
data-logging systcrn attachcd to it, and available in tlie strength ol'materials laboratory of the
Civil Engineering department. Tensile strength, percentage of elongation and elastic modulus
werc cvaluatcd by conducting thc [CIIS~OII tesi on tllc various fibres. Representative samples
of fibres were cul into lengths of about 8 cnl and were held individually between a slot of
lengtli 6 cm (gauge length) made in a thin card board or thicl< paper fibres were fixed in
position by cello tape or araiditc and tlic specimen so prcparcd was hcld lightly bciwccn the
two jaws of the machine. Then the sides of the paper were cut so that only the fibre will take
the applied load. The tensile load was applied gradually at a constant rate of 0.01 mmimin.,
till failure of the specimen. The diameter of the fibre was measured close to the centre of the
gauge length and the tensile strength (ie. at failure) of the fibre calculated based on the above
initial diameter of thc iibrc. A 111inimum of 15 specimens wcrc considcrcd and their nvcragc
value taken as the representative value of tensile strength of the fibre. A custom-made
software was used in the data-logging system for the above test. At the end of the test, stress-
strain curve of the fibre, (maximum) tensile strength (at failure) , ultimate strain of the fibre,
were automatically recorded in the computer system interfaced to the above testing machine.
From the typical stress-strain plot, elastic modulus of rhc fibrcs wcrc calcularcd using the

.. . .
~~lctlic~il 01 I I I I L I ~ I ~ tilngcnt I I ~ ( ) C ~ I I I ~ I S .
11 vic~ of'tl~c cxpcri~iic~it;~I test SC~ i~p is show11 in 12ig.3.3
anil a r'iical s11.c~~-strain plor is shown in Fig.3.4. 'i'hc physical properties of the Sour natural
fibres, evaluated as described above, are presented in Tabie 3.10.
3.3.3. Chemical Composition of Natural Fibres
C'hcinical coniposition of nnturnl fibres may vary born fibre to librc. llowcvcr. thc reported
prcdolninant chzmical constituents are: hcnii - cellulose: cellulose and lignin, the composition
of which will vary from fibre to fibre. In order to overcome the durability problem associated
wit11 natural iibrc in cement - 'cased composites, a proper ~~nderstanding of thc deterioration
mechanisnll(s) of the fibres in the matrix and in various other mediums (for eg, alkaline etc.)
on the chcmical composition of natural librcs will be different for various fibres. I-Icncc, it is
llccessary to determine the predominant chemical consrituents of various fibres in its native
fonn and dry condition, which will serve as datum or reference to evaluate the relative
performance of various fibres.
Hence, chemical anaiysis on ciean and well dried samples of fibres was carried out to
determine the co~nposition of henii - cellulose , cellulose and lignin contents of each type of
libre adopting standing testing procedures. A brief description of the procedures used in this
study is given Appendix B2. The chemical composition of the four tjpes of fibres as
deternlined by the above procedure, is given Table 3.1 1. Samples used for the chemical
cornposition of various fibres in powder form and In the fibre form after immersion in the
three mediums are shown in Fig 3.5(a) and 3.5(b) respectibely.
3.3.4 Evaluation of Performance of Four Natural Fibres and Cement Composites
(.A) Objective of tlze Investigrrfion
Several investigators have studied the durability of various natural fibres, such as: sisal, coir,
jute etc., in various ~l~cdiuriis and cxposusc conditions which has bccri summarized in
Table 3.12(a). Thc dul.ability of n;itusal fibre co~nposi~es exposed to various cnviroumcnts
have also been investigated, based on the changes in a chosen strength criterion
[Table 3,12(b)]. In spite of the above reported works, the effect of various ~nediums 011 the
chemical compositioi~s of natural fibers, have not been quantified and reported.
Morcovcr, Ihc durability of natural fibres has bccn ascertained by he vtlrioi~s investigators
based on the durability of coniposites which was evaluated on the basis of a chosen strength
criterion [Table 3.12(b)]. However, in reality durability of the composites cannot be

iicicr~n!~~~ii solely on the deterioration characteristics of' natural fibres. For example, fibre
debo:,inding, the effect of corroded fibres and effect of exposure conditions, would have a
Lili,,lilc~ti\~ i'l'li'cl 111 I.C(~IIC~I~~ tllc ~I!.CI,~II, 01. [IIC co~iipo\iLc. wllicil ih sol~glli to hc OSCC~ I 0
I
~111cic1 \[anil ~lic ilusahi lily 01'
lllc n;~ti~i.;~l IiI,~ch, hy carlicl. i~~vcsiigators. l'ossibly,
~n\t.stigatio~is on the changes in the strength characteristics of cement composites using
ilatural fibres in dry condition and after cxposing them in alkaline atid other environments
111aq' offer better insight into the actual deterioration process and to understand the
~ici~~rio~:~lio!i riiccI~:~~ii~~ii or I~:I~\II.:II
I ICIICC. LIIC
lil~scs ill :~lk;ll~~ic c~i\!iro~~iiic~its
cllcc~ 01 c~ll\;~l~~lc
I~ICCIIIIIII~ (C~~~CILII~I I~yiI~~ox~iIc ;111il socli~1111 II~CISOSIIICJ
il~iii li.csI1
water. on the durability of sisal, coir, jute and hibiscus cannabinus were investigated. The
cff'cct of the abovc mediums on some of the salient chemical compositions of fibrcs, \vhicli
are susceptible for dissolution, have also been studied. Compressive and flexural strengths of
ccmelit mortar specimens reinforced with thc abovc fibres in their natural (dry) condition and
will1 Ilic 'cor~.oclcci lihscs' (i.c., ll~c Iibrcs sul!jccrcd lo 'contin~~ot~s imrncssion'/ 'allcrnaic
wetting' and drying in the above mediums) were determined and compared with the strength
ol"contro1' or 'reference' specimens. Post-crack beliaviour is a measurc of ductility and it is
an important attribute of' libre composites, which can be evaluated by more than one method.
In this preliminary investigation, the ductility of natural fibre composites were evaluated by
two nppsoachcs, under as impacl load. 'l'lic perli)rmancc ol'slab spccimcns rcinli)l-ccd with
the four natural fibres, were evaluated under an impact load, based certain indicators.
The ob,jcctive at this stage of the study is Lo choosc the best natural fibre, from among the
/'our typcs consiclcrcd in thc study, bascd on tlicir rclativc pcrfol~~~~ancc in the abovc
investigations, and use it subsequently for all coi~iprehensive studies, as reported in this work.
i l),Selection of Mediums
Thrce different mediums, namely, (i) clean and fresh water (pH = 7.5); (ii) saturated lime
solution [Ca(OH)2] and (iii) a deci-normal (0.1N) solution of sodium hydroxide (NaOH) were
sclcctcd for studying thc durability of' fibrcs. Cliarigcs in the cliclnical composiiion of cach
lypc ol'llic above nlcdiun~s wcsc ohlaineil by lllc s~a~lilarcl [csl ~~.occiliirc ~ilc~ltic:~l io the one
used for determining the chemical composition of fibres in natural dry condition. During the
period of exposure of fibres in each of the above mediums, pH of the above media were

::;aintained constant at 7.5,14, and 13 respectively. The concentration of alkaline mediums
a12d dilraiion of exposure were fixed based on earlier reported work of Singh (274)
(2) iisperimental Procedure
ib1l7i.c~ ol' lcrlgili 15 to 70 C I ~ \VCI.C
. .
Ikcpt i11i1ncricd in scpasatc alr t~ght cont:~incss
coiltai~liiig (he:~bovc
nicdiums. At cvc1.y 24 IIOLI~S i~itcr~~~l, the fibrcs were Liili~11 0111 li.0111 L ~ c
respective containers, washed with plenty of water and dried at room temperature (28k5OC )
and then replaced in the corresponding container. This process of 'alternate wetting and
drying' were repeated for 30 cycles i.e, for a total period of 60 days. In order to evaluate the
pcrfi)rm:l~icc oSn:1tt11.:11 fihscs si~l!jcctcd lo 'nltcr.n:ltc wetting and tisying ', cyclcs, scpasalc set
01' I"II>Ic\ \ \ ~ I C l,cp( '~OII~II~~IOLIS~~ i~ii~~icr~c~l' t~pto 00 ~l:~ys i~i :~ir(igl>t co~~tai~lc~.s, /It 111c c11d 01.
the above exposure period, the fibres were taken out and their salient chemical compositions
were determined. Photo showing samples of 'corroded fibres' after exposure in the various
mediums, is shown in Fig.3.5 (b). Tensile strength of various fibres after exposure in the
three mediums were determined by testing the fibres in an ~lniversal tensile testing machine
(5kN) capacity at low-straill I.a(cs. 'l'lic icnsilc strength ol' rhc librcs ill clry condition wcrc
compared with that of the tensile strength of the fibres after exposure in various mediums. A
reference cement mortar (or a 'control mix') in 1:3 (cement: fine aggregate), with water to
cement ratio (wic) of 0.65 and a flow value 112, based on flow table test as per
1.S 2250-1981 [378], was prepared. Natural fibres conditioned in the various mediums were
iiiscctly i~scd Ibr casting the lihrc rcinlbsccd mortar beams ol' si/c 40x40s l GO mm, with a
fibre content of 1 % -by wt, of cement. Mortar beam specimens were also cast using natural
dry fibres (i.e. uncorroded fibres): to serve as 'control specimens'.
(C) Effect of Exposure Conditions on the Chemical Composition
~h'e chei~~ical con1positio17 and the pcrccntagc reduction in their composition of fibrcs after
60 days of 'altcn~atc wetting and drying' and alicr 'continuo~is immersion' in choscli
mediums are presented in Tables 3.14 and 3.15. From a critical analysis of the above results
following inferences have been drawn:
(i) Reduction in hemi-cellulose and cellulose contents of coir fibres are in the range of
32 - 68% and 38 - 73%, respectively, when coir fibres are exposed to alkaline
environmen~s. 'The above values are closer lo the values, when the same fibres are
exposed to fresh water. However, a wide variation in the reduction of lignin content
of the above fibre is observed, when exposed in alkaline environments (ie.8 - 5.3%),

fD) Eflect of E-vposure Conditions on the Tensile Strength of Fibres
('oniparing Ihc tenile strength of various fibrcs in dry condition (Table 3.10) with that of the
tensile strength of fibres after exposure in the various mediums (Tables 3.16 and 3.17)
fbl!o\ving inferences have been drawn:
I ) I'licrc is si~hstantinl reduction in tlic Lc~isile stsc11gi.h of all tlic libscs, in all th~
mediums irrespective of the type of exposure. The above phenomenon may be
attributed to the chemical dissolution of 'lignin' especially in alkaline mediums.
(ii)
Saturated lime has caused maximum reduction in the tensile strength of sisal, jute
A I ~ L I I ~ I ~ ~ Y C Ii';~llll;lhi~lt~h
I S lil>i.c\ ;111d the ilbovc Iibri's WCI.C co~nplctcly tlcsll.oyctl aftel.
00 days 01' 'altcl.11alc wclt~ng and drying' In the abovc mciliu111. '1'11~ abovc
phenomenon may be attributed to the absorption of alkaline solution into the higher
pores present in the above fibres [244, 274,2631.
(iii) Coir fibres are able to retain 20-40% of its original strength after 60 days of
'altcrnalc wetting and drying' in saturated linic.
(iv) Jute fibres could retain above 10-20% of its original strength after 'alternate wetting
and drying' in the above medium, thus performing better than sisal and hibiscus
cannabi~ius.
(v) In sodium hydroxide, coir fibres retain about 40-60%, whereas, the remaining three
iypcs of lihrcs could rctain only 10-20 4, of its original tensile sircngth, irrcspcctivc
of the type of immersion adopted.
(vi) Coir and sisal fibres were able to retain 50%-60% and 60% -70% of their respective
original tensile strength, thereby performing better in fresh water, for both types of
immersion, than the remaining two fibres i.e. jute and hibiscus cannabinus
considcrcd in this study.
(E) Strength Characteristics of Mortar Composites - Before and After Exposure in Various
Merliums
Compressive and flexural strength of natural fibre reinforced mortars under natural dry
condition and with fibres aftcs exposing them in llie various mediunis and under two types of
in~mcrsions arc prcscntcd in 'l'nblcs 3.18 and 3. 13. 'l'hc maximum strcngth - loss in llie rnorlar
composites (considering the three mediums and two types of immersion), are presented in

i nb!e 3 20 Comparing the above strength with that of reference mortar strength. following
lnfcrences are drawn
(I)
Compressive and flexural strengths of all types of fibre reinforced mortar
composites are less than the reference mortar strength (ie without using fibres),
when the fibres are used in their natural dry condition.
( ~ i ) Both the above types of strength of fibre reinforced mortar composites reinforced
with 'corroded fibres' (ie. fibres aftrer exposing them in various mediums) are also
lcss than the rcfcrc~icc niortar strength and that of mortars rcinforccd with fibres in
the11 natul'll diy condit~on I'hc abovc plicnomcnon 1s true Sor all lypcs 01' fibrcs
and types of immersion considered In general, this may be attributed to the
'enibrittlement' of fibres. consequent to their exposure in the various mediums.
(iii) Strength - loss is 'more severe' in mortar specimens, wherein, fibres subjected to
'alternate wetting and drying' in thc various mediums, were used.
(IV)
(v)
Cons~dering the strength - loss of various fibres and that of fibre reinforced
mortars, it can be inferred that certain types of fibres are susceptible for
deterioration even in water, apart form alkaline mediums.
Strength - loss of cement mortar composites reinforced with 'corroded fibres'
indicate that it niay be duc to tlic c~iniulativc cfrcct of thc inialrix and that of'
corroded fibres on the strength and bond.
(F) Durability Studies on Four Natural Fibres and Mortar Composites : Summary
Based on the durability studies on the four types of natural fibres and on the cement mortar
composites reinforced with 'corroded fibres', the salient results obtained / inferences drawn
can be sunimarized as :
(i) There is substantial reduction in the salient chemical composition of all the four
natural fibres, considering their exposure in the three mediums and the two types
of immersion adopted.
(ii) In most cases, 'continuous immersion' is found to be 'critical', affecting the fibre
characteristics.
(iii) Effect of fresh water on hibiscus cannebinus is 'very severe', than in the other
three natural fibres considered.
(iv) Coir fibres retain about 20-40% of their initial tensile strength, considerillg the
three mediums and the two types of immersion.

(v)
All other fibres. in general, have lost their entire initial tensile strength after
exposure in the three medium, except, sisal fibres which retain above 60-70% of
their initial tensile strength after exposure in fresh water.
i Stscnglh - loss afics cxposurc in lies11 water may bc attributed to
(vii)
microb biological' action on the fibres.
Compressive and flexural strength of all natural fibre reinforced mortar
composites, using 'corroded fibres' are less than the corresponding strength of
reference mortar (i.e. without fibres), and that of mortar composites reinforced
w~th librcs in dry condit~on.
(viii) 'l'lie strength -loss is high, when the fibres exposed to alkal~ne mediums are used
(ix)
(x)
in the mortar composites. This clearly indicate the 'exclusive effect' of alkalinity
on the fibres and their consequent strength-loss when they (i.e. natural fibres ) are
used in cement composites .
Reductiori in the compressive strength of ccmcnt mortars coniposites with
'corroded fibres' is 30%-60% less than that of' cement mortar w~lh fibres in dry
condition. The above phenomenon is found to be independent of the type of fibre
used and the medium of exposure.
Based on overall performance, coir and sisal fibres have the potential to be used in
cement matrix, when compared to the other two fibres, ie. jute and hibiscus
cannabninus .
(G) Imapct Strength of Mortar Slabs: Comparative Performance of Four Natural Fibres
( 1) Theoretical Background
One of the main advantages of using fibres in a cement/cementitious matrtix is to convert a
rclativc by brirtlc ni~~tris, to gain and maintain ‘toughness' and cluc[ility' in the composite.
7 .
I he capability to absorb energy, often called 'toughness' is of importance in actual service
conditions and during the service-life of fibre reinforced composites, when they are subjected
to static, dynamic and fatigue loads. 'Toughness' evaluated under impact loads, is the impact
strength. Apart from ensuring durability of natural fibres in the cement matrix, it is necessary
lo stildy Ihc inipnct strength charac[cristics of natural librc rcinfosccd ccn~criticc~~ic~ititious
composilcs to understand their behaviour and assess their performance for various potential
uses.

impact resistance of fibre reinforced composite can be measured by using a number of
different test methods, which can be broadly grouped into the following categories: (i) Drop
~veight (single or repeated) impact test; (ii) Weighed pendulun charpy-type impact test;
(11i) l'rojcctilc impact tcst; (iv) Esplosion-impact test; (v) Constant strain rate test; (vi) Split
l lopl

in cement mortar 12, reinforced with the four types of natural fibres (coir, sisal, jute and
ii~biscus cannebinus) at four fibre contents (0.5%, 1 .@%,I .5% and 2.0% - by weight of
cement) and using three fibre lengths (20 , 30 and 40mm). Ordinary Portland cement and
qii;liity sivcr. sand wcrc LISC~. TI1e rccluircd clunntity of wntcs was dctermincd by tllc flow
1,11)11' li'sl lllc [nostas [nix, co~~i~cspoilii to ;I floiv vi~luc 01' I IO'X,, as pl.cscsibcd in
IS: 7,250-1981 13781. The water content corresponding to the above flow value is 0.47, which
%,as maintained constant for c,asting all slab specimens and for all mix combinations
considered for this test. Altogether 147 mortar slab specimens (144 mortar slab specimens
with natural fibres and three without fibres) were cast and cured for 28 days.
i\[ [tic cnii ol'ilic above curing pcrioti, the slab spccll.licns wcrc rcstcd In tl~c pso,jcctilc impact
test set-up [Fig3.9(a)], with the specimen mounted on a M.S.frame. The height of fall
(i.e. 200mm) and the weight of metallic ball (weighing 0.475 kg ) were maintained constant
for tcsting all the specimens. 'I'he test set-up was so adjusted such that the nletallic ball will
fall exactly at the centre of the specin~en and it was also ensured that the four edges of the
spccimcns wcrc Srccly supported. For cacli slab spccimcn, [tic nun~bcr 01' blows reqiiircd ibr
the appearance of the first crack, the crack-width and crack-length at failure, were noted. The
initiation of crack was based on the visual observation and ultimate failure was determined
based on the number of blows required to open the crack in the spec,inlen sufficiently and for
the propagation of the crack through out the entire depth of the specimen. It was observed
that thcrc is not niuch variation in thc rnaxim~im crack wid111 ol' slab specimcris with fibre
conicnl and typcs of librcs. I-lencc, the maximu~ii crack width and crack depth (i.e. entire
depth of the slab specimen) were used to compute the energy observed by the specimen.The
impact energy per blow was conlputed for the (chosen) weight of the ball and its velocity at
the instant it strikes the mortar slab specimen. The details of the above computation is given
Appendix C5. The impact energy absorbed hy tile mortar slab spcciiiiens were computed
based on thc number ol'blows scquiscil to iniliatc tlic lisst csncli and the number 01'
blows
required to cause ultimate failure and the impact energy per blow (i.e.0.93 Joules). The
impact energy absorbed by the various fibre mortar composites (i.e. slab specimens) are
given in Table 3.21 and they were compared with that of the reference mortar specimens, to
evaluate the performance of the mortar slab composites under an impact load. Based 011 the
encrgy absorbed, llie maximum crack width (w,),
crack length (1,) at failurc, tlie illtimate
crack resistance (R,) and the crack resistance ratio (C,,) were calculated as outlined in the
following section and presented in Table 3.22.

(4) i lieorot~cai Bas15 for Evaluating I'eribrmance
\$'hen a slab is subjected to a load released from a defined height thereby constituting an
inipact loading, in general, there is a loss in the potential energy which is absorbed and
dissipated as strain energy, causing cracks due to stresses developed in the element. The
\r~titli oSc~.ach tli~ls clcvclopcct is related to [llc ~iltc~l!,ity 01' Llic cncrgy, Lllc arnoLliiL ol'cncrgy
absorbed ;uid tlic propzrties of concrete. 'l'he energy absorbed dissipated in the for1 of cracks
and patterns of cracks are produced from the impact loading and that the crack pattern is also
dependent on the properties of the material (i.e. composites in this case) [395]. A relationship
for the potential energy (P.E.) of an impact loading due to a falling body and the strain energy
cl~s\ip;~lcd in Ilic cracks (Iial ticvclop In a tt~rgct, can he cxprcsscil b~~sccl on I'i~nclirrncnials of'
'k,lcclia~~ics oI'Malcrials' approach and ns proposed by Kankam (3951 is given by ,
Ye = R,, I, d, w, .. .(3.4)
whcre, N = numbcr of blows; e= energy ( in Joules) blow; I, = total length of cracks;
d, = maximum depth of crack; w, = n~aximunl width of crack. Using eqn(3.4) , the ultimate
crack rcsislancc (I,,)
of tlic mortar slab spcclmcns were calculalcd A d~mensionless faclor
'~n~pact crack-resistance ratio' (C,) as proposed by Kankam [395] and as given by Eqn(3.5) ,
is also evaluated for the various slab specimens.
whcrc C, = i~npact crack-resistance ratlo; f,,, - (cube) comprcsslve strength of reference
mortar in Ml'a (i.c. Sor 1 :3 mix and I'or a spccirncn six of 70.7 x 70.7 x 70.7 mm). Kankam
13951 used the above approach for studying the resistance to impact loading of concrete slabs
reinforced with palm kernel fibres, by loading it as a pavement slab (i.e. placing the slabs
over sand bed). He has assumed that the total computed energy imparted to the slab specimen
is fully absorbed by it alone, even though the actual experimental condition was not close to
thc Llieorcticol npp~,oncli proposcci and ~~scd by Iiim ill his i~iv~stigiltiolis. II~WCVCI., in ~111s
study, the experimental set-up closely simulates the theoretical approach and hence Eqn,(3.4),
is suggested to be used with confidence to study the behaviour of specimens subjected to
impact loading.
The method proposed by Kankam [395] involves lengthy calculations. Hence, in order to
cvaluatc quantitatively tlie improvclilcnl in Lhe impact rcsislklncc characlcristics, cspccially ol'
fibre cement 1 cementitious composites easily, a simple parameter called 'residual impact
strength (I,)'
has been defined and it is given by Eqn.(3.6).

I '11c1.g~ II~SOI.~>CC~ i~pto ultimate li~ilurc
io~'i\~~~ci
i1i1o lhc 1ii:11rix.
71'!ie impact resistance (R,) , residual impact strength ratio (I,,)
, impact crack-resistance ratio
(C,) and the condition of fibre at ultimate fibre i.e 'mode of failure' were considered as the
pre-set indicators to evaluate the relative performance of the cement mortar natural fibre
reinforced slab specimens, when subjected to an impact load.
(5) I,;vaiu:ition ol' I'c~for~nancc Under Impact I.oad
From the results presented in Table 3.21, it can be seen that due to incorporation of the four
natural fibres in the mortar slab specimens the impact resistance in terms of actual impact
energy absorbed, has increased by 2 to 18 times than that of the energy absorbed by the
'reference mortar slab specinien', considering all the types of natural fibre co~nposites and the
rangcs ol' librc contciits and librc Icngths considcrcd and the impact energy for initiation of
first crack and at failure of the composites. Of the four types of natural fibres considered, coir
followed by sisal fibre reinforced slab specimens have absorbed higher impact energy (in the
above order). The highest impact energy by coir mortar slab composite was 253.5 Joules and
that the energy absorbed by sisal mortar composite slab was 121.2 Joules, both at fibre
content = 2% and tibe Icngtli = 40nim. I~icorporation or natural fibres Iiavc contributed to
substantial improvement of 'post - crack behaviour', especially, after the initiation of first
crack in the composites, irrespective of the type of natural fibre used, especially at higher
fibre contents (i.e.l%). The residual impact strength ratio, as defined by Eq~(3.6) for coir
fibre composite slab is about 3.91 and that for sisal fibre composite slab is 2.06, whereas for
the other conipositc slabs, I,, is lcss than 2 and rnngcs bctwccn ncarly 2 - 1.8. Comparatively
poor performance of post - crack behaviour of jute and hibiscus based composites, may be
attributed to the reduction in the tensile strength or loss in strength of fibres due to the
alkaline medium present in the cement system (i.e. cement mortar composite). From the
results on crack resistance and crack resistance ratio presented in Table 3.22, it is seen that
(b
the rnaxiniul~i crack width and maxiinurn crack length do not exhibit appreciable variation
with respect to fibre content, fibre length and type of fibre. On the other hand, the ultimate
crack resistance follows the s&e trend as that of the ultimate impact resistance, followed by

i!scll, jii!~ and iiihisc~is compos~tc slabs, tnkcn In thai ordcr. Maxtmum ultinlate crack
rcsistancc had bccn found to bc ol'fcrcd by coir fibre rcinforccd slab specimens, at identical
conditions (i.e. at fibre content = 2.0%; fibre length = 40 mm) as that of the impact resistance
of the above composite slab. The crack resistance ratio generally shows an increasing trend
with increase in fibre content and fibre length. However, the average increase in the crack
reslstancc ratio (with rcspect to the reference mortar slab). is the highest for coir fibre
rc~nlbrced slab specimens, (i.e.3.28). whereas, for sisal reinjbrced slab specimens, the above
parameter is 2.48, considering the range of fibre contents and fibre lengths in the above
investigation. Thc maximu~n value of average increase in the crack resistancc ratio attained
by coir fibre mortar composite slab (as stated and given above) is 1.3 - 1.8 times that of the
other three fibre reinforced slab specimens. Sisal fibre mortar composite slab could attain
about 53% 01' I,, valuc and about 76'K ol'thc avcragc incrcnsc in llic crncit resistance ratio. A
closer look of the impact resistance reveals that even though the impact energy absorbed by
sisal fibre composite slab at iniation of first crack is nearly equal to that of coir fibre
conlposite slab, the latter exhibits better 'post - crack behaviour' and hence the ductility of
the composite.
Considering thc nature of Ijiliirc, it uns obscrvcd that plain mortar slab spccimcns brokc into
pieces, whereas, natural fibre reinforced mortar slab specimens, had a number of multiple
cracks. Moreover, 'fibre pull -out' was observed at ultimate failure in the case of coir fibre
mortar composite slabs, whereas, 'fracture of fibres' was observed in all other composite slab
specimens. The above failure mechanism is typical of natural fibre reinforced composites, as
observed by other investigators [406, 4071.
Of the two approaches to evaluate the performance under impact load of composites, as
discussed above it could be seen that the parameter 'I,,' is simple and easy to use and can
describe the 'post - crack behaviour' and to evaluate the ductility of the composite. Hence,
the parameter 'I,' alone was used for the comprehensive studies on the chosen composite, in
this study.
(H) Fibre Selected for Further Studies
Of the four nature fibres considered for the various investigations as detailed in the above
sections, only coir and sisal fibres and mortar composites reinforced with sisal 1 coir fibres
have yielded better results have performed better, than the remaining two natural fibres
(i.e. jute and hibiscus). Among coir and sisal, even though, coir has the best overall

pxformance, sisal fibres have also exhibited comparable and nearly equal performance, as
:li

I
(v)
At the end of 360 hours. the fibres were air dried for a period of 240 hours and their
iicight tiotcd at 1nter~a15 of' 114. 48. 73, 06, 120. 144, 168,192, 31 6,240 hours
~espcc~~\ciy
Steps (ii) and (IV) completes 'one cycle' of 'wetting and drying'. During the above
cycle, the diameter of the (wet) fibres were also measured, using a micrometer.
(vi) After the 'first cycle', the fibres are kept immersed in water for 360 hours and the
process ill steps (IV) repeated to complete tl~e 'second cycle' At the end of 'two
cycles' the experiment was terminated
The change In diameter and water absorption (%) at karious stages of 'alternate wetting and
drylng' cycles are tabulated and also plotted to understand the 'dimensional stability' of sisal
fibres and to draw inferences from their behaviour.
3.4.2 Worliirbility Ch;\rii~tcri~tics
(A) Workability of Cement Mortar Composite - at Various Aspect Ratios (r = 0 -300)
/ 1 ) Choice of Method
Bj the definition of workability, the composite nature of property and, its dependence on the
type or construction ~md ~iicthods 01' plnclng compacting and lin~shing, thcrc is 'no single
test' that can be designed to measure workability. In spite of the above lin~itation, almost all
workability tests so far proposed by various investigators and which have found a place in
various National and International standards, are 'all empirical tests only', wherein,
workability is expressed as a single figure [I]. Such tests are: slump, compaction factor, V-B
tlme, 'inverted slump cone' etc. The above tests are to be used as a simple quantitative
statement of behaviour (of the niaterial - concrete etc.) under particular circumstances [I].
Hence, they are referred to here as the 'conventional tests' or 'empirical tests'. For mortar,
the only test specified in Indian standards, is the 'flow table test'. The above test is a measure
of 'flowability' of mortar. It has a practical significance in that it indicates the ease with
which the material (i.e, mortar) call bc placed Iapplicd onto a surfacc. Moreover, for fibroi~s
material, there is no specific standard available so far, in India, to study the workability.
Hence, in this study, 'flow table test' was chosen to study the workability of sisal fibre
cementitious composites and to have a quantitative assessment. Flow table test with
composite mortar specimen is shown in Fig. 3.6.

( 2 i'i[>\\.. ~
Values of Sisal Fibre Reinforced Cement Mortar (at various aspect ratios)
.T!on. table test' was conducted on 1.3. 1 :4 and 1 :5 mortar, adopting Indians Standards.
( IS 32.50 - 13781 ) I'lic nbovc miscs rvcre cl~oscn as (hey cover a range ol'rnixcs frorn richer
to Icaner and cover a wide range application in Civil Engg. The water-cement ratio (WJC)
required for each mix was determined from the pre-set flow value to be maintained for the
respective 'control' (reference) mortar mix. The above WIC was also adopted for all mixes of
sisal fibre cement mortar, after making adjustments for the water absorbed by the fibres
(I c sisal lihscs). 'l'lic details ol'mis proportio~i of rcfcrcncc ccmcnt mortars arid that of sisal
iibres reinforced cement mortars are summarized in 'Tables 3.23 and 3.74, respectively. The
objective of above test is to understand the flow behaviour 1 fluidity of sisal fibre cement
mortar composites, in relation to the reference mortar, for a wide range of values of aspect
ratios of the fibre (i.e. aspect ratio ranging between about 30 to 270 ). The flow values were
iic~ct.ni~ncil lbr. six dl!lirr.cnt aspcci ratios in thc rangc of300 and six
diff'crcnt fibre contents
(:.c. @ 0.25%, 0.50%, 0.75%, 1 .0%, 1.5% and 2.0% - by wt, of cement) at the specified W/C
ratio (Table 3.24). Fibre content was expressed as % wt. of cement, so as to exercise better
control over the experimental measurements and as it more reliable than the other approach
based on volume. The range of fibre contents are adequate to provide not only an exhaustive
data, but, cover the range generally reported in the literati~re and Illat can be adopted in
practice \villioul i~sing any nctmiutures or mechanical mcalis of' molci~ng. Allogcthcr tlicrc
were 11 1 combinations (108 combinations with sisal fibres and 3 combinations without
fibres) for studying the flow values of sisal fibre cement composites at various aspect ratios
and fibre contents. 'I'he results of the above test and discussion based on it are given in
Chapter 4.
(U)
Workabili!y (IJ F!yash-Cenrajt Mortnr Cotrrposif~. - rrt n COIJS~NII~ AS~L'CI Ratio
(I = 200)
From the flow values of ccment mortar composite at various aspect ratios, it is possible to
identifyiselect the 'desirable aspect ratio', such that the better workability of the composite is
ensured. Once such an aspect ratio is identified, then matrix -modification by a pozzalana i.e.
flyash in this study, can be attempted to understand the role of the pozzolana used on the
workability and strength characteristics of the composite. Hence the flow values of sisal fibre
flyash-cement mortar composites were studied for 1 :3.1:4 and 1 :5 mixes. OPC was partially
replaced by flyash (ie. @lo%, 20%, 40%, 60%, 70% -by u. of cement) and the yield of the
mix adjusted accordingly. Fibre contents (0.25%, 0.50%, 0.75%, 1.0%, 1.5% and 2.0% - by

itc~g!;t of'ceiicnt] and sisal fibres of length 20-3Onlnl (I c at constant aspect ratio=200) were
d~iopted for the above study. All together 42 con~binations (i e. 36 combinations with sisal
!i51ts a~id 6 comblnations without fibres} were considered for determining the flow values of
i.c!ncnt~t~o~ls riiorla~ composites S~sal Iibrcs wcrc li~pl lmmcrscd in watcr Sor about 5
niinutes before mixing them in the mortar. The details of the cementitious mortar mixes for
the above study are given in Table 3.25(a) to 3.25(c) for mixes 1 :3 to 1 :5, respectively. For
each mortar mlx considered, flow values at various (W/C) ratios were determined by the
flow table test' The results of the above test and generation of flow curves etc., are given in
C'li,~l-~ic~ 4 ,\nJ dl~cilsscd
3.1.3 Rheological Characteristics
(A) Rlteology of Cement Mortar Conlposites nt Various Aspect Ratios (r = 0 -300)
(1 1 Measurcnient of Rheological Properties
I'IOIICCI
III~ LVOI I\ 01' I ~I~ICISLIII I I I '111d llic S ~I~SCCILICII~ IIICOIC(ICLII ,]ll~tl~i~il~l~ll by I allcl sall and
Bloomer [145], led to the establishment of the principle that the flow properties of fresh
concrete, can be approximated to the 'Bingham model' and that the two constants 'g' and 'h'
in the 'two-point test' of workability, were respectively measures of the two 'Bingham
con st ants',^ (yield value) and 11 (plastic viscosity) . Tlie relationship between the Bingam
conslanls is glvcn by I;qn (7 7)
where T = value of torque; N= speed in the two-point test apparatus/equipn~ent.
Apart from the above method, there are several 'rheometers' available Internationally based
on research and development carried out in Swe&i, France and other countries.
However, in spite of the above recent developments, following issues still remain open:
(i) There is no standard developed and accepted for the test using 'rheometers' / the two
point worl

ilc !IIII>OI~CCI. 111 (;~cL ;I(
Lllc [iili~ O~'c;il~~~).irlg 0111 [/:ih S~IIC~Y sllcll ~~[lllj>lll~llt L1I.C ~lI1110~~
not a\ ailablt. nor manufactured in this part of Country i in this Country.
E icncc the use of such test setups were ruled out for the present study. However, it has been
reported in literature that attempts have been made earlier to use 'shear box test' and 'triaxial
ics~' li>r. mcasi~scrncnt ol' rhcoiogicnl propcrtics of conventional concrctc j408 to 41 01. SLICI~
t~ht :i:c[lioclh iirc si~iiplc lo ilsc :mil help to Incasurc ccrtain S~~ndamcntal propcrtics of material
like 'cohesion' (c) and 'angle of internal friction' (cp) which can be taken as measures of
helogical properties of concrete etc. Moreover, the usefulness of the above tests have not
bccn investigated Ibr fibrous materials arid reported. In view of the above, it was decided to
i~sc 'hos shcar test' to study the rlieological characteristics of sisal fibre cementitious mortar
corilloxifcs, in [lie p1.csc111 iri\;csiigiiliorla 'l'hc lest sc~ -11p Sos [lit iliscct slicar. box test arid Lhc
two different sizes of shear boxes are shown i11 Fig. 3.7
(3) 13xpcrimcntal I'roccdure
The rheoiogical properties of sisal fibre reinforced mortar at various aspect ratios (i.e, same
as that fi)r dutcsinining 'Ilow values' of mortar) were studied for I :3, 1 :4 and 1 :5 cement
mortar, by conducting 'shear box test' according to IS: 2720 (Part XIII) [411]. The 'shear box
test' is a popular test set-up used in Geotechnical Engineering for determining the cohesion
(c) and anglc of internal friction (cp) of soils. 'The size of shear box used for thc test is 60x 60
mn and which can accommodate 25mm thick specimen. Each mix is sheared at various
normal loads of 50, 100, 150, 200 and 300 kPa, from which the slicar stresses can be
computed using Eqn.( 3.8)
Shear load
1
Shear stress of the mix = Sectional area of the box .,.(3.8)
'I'hc shear load at lililurc ol'thc spccimcn (i.c. Lllc ~nis) was notccl. I:ro~ii Llic plot ol' 'nornial
stress' verses 'shear stress', cohesion (c) and angle of internal friction (cp) were determined.
A brief description of the 'shear box test' along with a sample data and calculation are given
in Appendix C3. 'C' and '9' were determined for the cement mortar composites at six
different aspect ratios and at six different fibre contents (i.e. for the identical values used for
dctcrmi~ic the flow valiics of ccmcnt mortar composilcs) for tlic prc-dctcrminccl WIC ratio Ibr

,,,, ~,,ix -A The details of various mixes are given in Tables 3.25 (a) to 3.25 (c). Results and
+L,,
:i!sciissicsn b:isod ori tllc obovc tcst arc given in Chapter 4.
(8) Rlzeologjl of FIyaslz - Cemmt Mortar Contposites at a Constant Aspect Ratio
(r = 200)
II i 7, 1 4 and I .5 inlses, by pattially replacing Oi'C by fiyash (1.c 10%~ 20%,40%, 60%
,i:~i! 70'!'0 - by wt ol'ccment) and at SI\ fibre conients (1.c. same as lor studies with various
aspect ratios), The values of cohesion ( c) and angle of internal friction (cp) were determined
adopting the same procedure as that of cement mortar composites, for the mixes given in
-1'ables 2.25(a) to 2.25(c). Comparison of results froin the various methods, influence of
aspect ratios etc are discussed, based on the results obtaincd by the above study, and
p~cbcntcd in Chaptcr 4.
(C) Effect 'Slzear Box' Size on Rheological Clzaracteristics
For the rllcoiogical studics of composites, the original size i~scd in Gcotechnical Engineering
for 'shear box test' was retained and rheological properties were obtained, at the first
instance. However, it will be of interest to see whether there is any 'size effect' of the
experimental setup on the rheological properties. Hence a different size of shear box having a
plan size of 8Ox80mm was used. Both the 'normal size' (plan size:60 x 60mm) and the above
'modified size' were used to determine the rheologial properties of only 1 :3 plain mortar for
six WIC ratios (ie.0.3%, 0.4%, 0.5%,0.6%, 0.7% and 0.8% ). The results from the above
specimen sizes were analysed to ~tnderstand the influence of 'size effect', if any, on the
rheological propcrtics of' plain mortar. 'l'hc rcsulis and discussion bascd on the above arc
given in Chapter 4.
3.4.4 Strength Characteristics
Of the three mixes, only for the rich mix, namely, 1 :3 strength characteristics were evaluated
both for cement mortar and Ilyash-ccmcnt mortar composite slccimcns. Compressive
strength, flexural strength and split-tensile strength of cement mortar specimens of the above
mix were determined at four ages (i.e.28, 56, 90 and 120 days of normal curing) and at fibre
contents (ie. six ranging from 0% to 2.0%) and at a constant flow value (i.e.112.5%). Flyash
was also used to replace OPC partially ranging from 0% to 70% for the strength studies of
mortar spccimcns. F1.on1 thc 'flow curves' dcvclopcd by L11c worl

t;i:cr-hinder (M'IR) ratio was selected for preparing the binary blend (i.e. flyash + cement )
!:lortar. bascd on the constant flow value (i.e.112.5). No adjustment was made for the water
;:i~sot.i~~inr~-c~ij~i!~iiy ol' sisal Iibrcs, as the fibres wcrc prc-soaked (at least for 5 minutcs) in
:'scsli \vatci. allL! il~cii:scci in ihc nioriar !or casting various Lest specimens. W/B ratio for each
combination of mix for a constant flow value of 1 12.5% is summarized in Table 3.26.
Altogether there were 42 con~binations (5 conlbinations with cement and flyash: 30
combinations with cement flyash sisal fibre; 1 combination with OPC; 6 combinations with
()I)(' 1
sis:11 lii~sc). l)clr~i Is ol'clc~i~c~~ts c:!sl Iilic sizc ol'spccii~ic~i, 110. of spccirncns, tola1 no.
ol' spcci~ncns cast Sor each combination of' mix etc, arc given in 'I'able 3.27, for the flexural
strength of beam specimens of the mortar composites. After casting the mortar beam
specimens, they were cured in water for the specified ages and at the end of the respective
curing period, the specimens were first tested for their flexural strength as per
IS 103 1 (Pt8) [350]. Compressive strength of the specimens were determined by using onc of
[i~c l'raciurcd (broken) picccs 01'
~hc bcam spcci~ncns (alicr tietesmining [heir llex~lral
strength) and testing them as per IS 403 1 (Pt8) [350]. Split- tensile strength of specimens were
determined by using another fractured (broken) piece of the beam specimen and tested by a
'novel nicthod' suggested by I-lannant [412] (also reported in the book titlcd: on, 'Concrete
Technology' -vo1.2, By:D.F.Orchard, Applied Science Publishers Ltd., London, Fourth
edition, 1079, at pages 91-95). A brief description of the above method is given in
Appendix C6. The tests standards adopted for the above three types of strength tests are also
summarized in Table 3.28. Fig 3.8 shows the schematic view of the above test. The results
iuid discussion bascd on thc strcngth tcsls are given in Cliaptcr 4.
3.4.5 Strength Characteristics of Mortar Slabs
(A) Mix f'roporfio~rs
~lexural and impact strengths of sisal fibre reinforced cementitious composites were
evaluated by testing slab specimens (size: 300x300~20 mm; 1:3 mix). All together,
42 combinations of mixes were considered for the above investigation. For casting slab
specimens, WID as givcn in Table 3.26 was used. Impact and flcxural strengths wcrc
dclcrmincd at o constant llow vuluc and at Sour agcs of normal c~~rinj: ( i . ~ . 11L 28, 56, 90 and
120 days). Fig. 3.9 and 3.10 shows the test set - up for the impact and flexural strengths of
mortar slabs.

S!ab specimens of size 30Ox300sI8mm were cast using 1:3 cement mortar and by partially
ii,pl;~i,ing ccinc!ir in tile nbo\,c nii.; \i.itii flynsi) ranging from 0%) to 70% (i.c. 096.1 0941, 20%,
4ii0i,. hO",, ,i1~.1
I.Oo;i,
70'k,) Si\: lihrc coiitcnls wnging Sroni 0':O - 2.O'K) (0 35%, 0.50'%, 07ji1/0,
l 5's and 2 0% - by wt. of cement/binder) were used in the cementitious mortar
composites WIB ratio corresponding to a flow value of 112.5% (i.e.0.47) was determined by
flow table test for l:3 mix and maintained constant for all mix combinations considered for
tile above study. Altogether 503 mortar slab specimens (432 mortar slab specimen with sisal
1;hlc.s mi 711 spcclnicns \v~tlioiii lihrcs) werc cast and curcd for 28. 50, 90 and 120 days. At
tlic end of the above curing periods. the slab specinlens were tested by the projectile impact
test [as described in Section 3.3.4(G)] and the various parameters for evaluating the imapact
strength characteristics, as described in the above section, were considered and evaluated.
The results obtained were also compared with that of the impact strength characteristics of
rcfcrcnce mortar slabs. undcr identical conditions along with the parameter 'I,,',
the perfon-nlance of sisal fibre cementitious mortar slabs.
(C) Flexural Strength of Mortar Slab
to evaluate
Flexural strength of mortar slab specimens were determined by a four-point loading system
and using the 5kN capacity Universal tensile testing machine available in the Dept. of Civil
Engineering. A computerized data-logging system was intcrfkced to thc above test set-LIP for
acquiring data and processing them, through a software exclusively developed for the above
purpose. The view of the above experimental facility is shown in Fig.3.8.
For the above test, slab specimens of size 120x90x20mm were cut and remo~ed from the
fractured slab specimens obtained from the impact test of slab specimens of size
300~300x1 8mm. For each slab specimen for thc flexure test from 504 con~bination of mixes,
the load versus deflection values were obtained through LVDT and logged on to a computer
and a plot of load vs. deflection obtained using the specially developed software, wherein the
load is measured at the loading position of the specimen used in the test. Along with the
above plot, the maximum load and deflection at failure are also displayed in the system and
Ioggcd on to thc computer. From thc abovc observations, flcxural strcngth of ccmcntitious
mortar specimens, which is representative of the flexural strength of slab specimens, were
calculated using the formula given in Appendix C7,

1 5rit.f description of the flevural test set-up (i.e, the four-point loading system) and its
c:!!ihr:it~t-~r and conrparison with norrna! testing procedure of tiles as per IS coda1 procedure
5,; coir fibre reinforcelnent mortar siab specimens.
3.4.6 I)t~ritl)ilit> of'Sis;ll ITihr-c Ccmentitious composites
1)urabiIily ol'a matcrial, in gcncrai, is dciineil as lllc scrvicc /ilk of a matcrial ~~ndcr givcn
en\rironmental conditions. The above definition holds good for all concrete and cement 1
cc~ncntitious conipositcs (reinforced with artificial fibres 11ke steel etc.) I-Iowever, in the case
of' natural iibre composite. not only the (external) environment, but also the internal
environment in the matrix (i.e. alkaline medium), play a combined role ill determining the
durability of natural fibre composite.
Even though, durability characteristics of natural fibres (sisal etc.) and cement composites
have hccn sti~dicd as dcscribcd carlicr (Scction 3.3 4). it is also necessary to study the
durability of sisal fibre cementitious composite, as such to understand and evaluate its
behaviour as a material and to obtain a comprehensive view of the overall behaviour in terms
of loss in strength of the composite after exposure in an aggressive medium like sodium
hydroxide (NaOH). With the above objective, durability studies on the cementitious
coinpositcs, wcrc also studied, by co~iducting two typcs of tcsts or1 thc composites.
(B) Experimental Procedure
Slab specimens of size 300 x 300 x 18 mm (1:3) were cast under identical conditions as that
of specimens for strength studies. After the specified period of normal curing, the slab
specimens were kept immersed in NaOH solution (prepared at 0.1N) for (another) 28 days.
D~~ring the period of cxposurc In thc above all

.-;.j!C'i. Klie resiilts from the above tests were used to understand the behaviour of slabs
(i.c, cc.n~c!:titious composites) in an alkaline environment and to evaluate the durability of the
ccm:.!titious composite, which are presented and disc~issed in Chapter 4.
3.5.1 I~:sperimontal Procedure
In order to explore the applicability of the various mixes and approaches in the development
01' a suitable product using sisal fibre con-iposites~ investigations on development of
corrugated (roof) sheet was sclcctcd. ' he abovc product, if' successl'ully developed and its
potential established, has a very large market world over and provide a feasible and a viable
solution for roofing in the housing sector especially in developing countries. Hence
corr~~gated sheets using the above conlposite have been taken up for comprehensive
investigation.
('orrug;~~cxl A(' s1icc.l~ of' sizc i .Oil1 s 1.2m s 6mm (com~iic~.cially ;~vaili~bIc was uscd as a
mould to cast sisal fibre cementitious composite corrugated sheets of sixe 250 x 500 x 6 inm.
1 :3 mix which is richer than the other two mixes (i.e. 1 :4 and 1 :5) was selected adopted to cast
the sheets using flyash to partially replace OPC. Replacement of OPC by flyash was
restricted to a maximum of 30%, as beyond that level, it is not expected to yield comparable
stl.cngths. 'Thcrcf'orc, only thrcc rcplaccmcnt lcvcls of Ilyash (i.c. l O'%,
2O1X/;, and 30'!4)) were
adopted for the above investigation. However, six fibre (sisal) contents in the range of 0.25%
to 2.0%, were considered, similar to the strength and durability studies on the cementitious
composites. All together 25 mix con~binations were considered (one without fibre and flyash;
6 combinations without flyash but with sisal fibres and 18 combinations with flyash and sisal
fibres). For each mix combinatio~, six sliects mlcrc cast. Watcr contc11t rcqi~ircd for each
combination of the mix was obtained from the flow curves developed earlier for 1:3 mix,
with and without flyash and with and without sisal fibres, at a constant flow value of 50. W/B
ratios for various combination of the mix at the above flow value are the flow curves for 1 :3
mix (with and without sisal fibres and for various replacements of flyash). The quantity of
materials required for casting sheets are summarized in Table 3 $29.

Ca.vting Procerlnre
.\ 5ricfdcscription of'thc casting procedure is givcn bclow:
ri)
(ii)
A moulding frame made of MS flat (size 320x500 rnm) is kept over a GI sheet (size
greater ihnn the mould). was cleaned and kept on the table vibrator. A plastic sheet is
pinccd in hciwccn [he liamc kund ihc 61 shcc~, to provide 21 smoolh s~~rlice for casling
and to help demoulding easier.
I~rcshly mixcii mortar according to thc rcquircd proportion was carcfillly placed
within thc mou!d frame and spread to cover the entire area, with the help of a trowel
arid properly leveled.
(iii) 'l'ltc inoitar niis was sprcacf irtio a iiniii)s~n iliiclincss by lirsr !inisliing with a [rowcl
and then with a straight rule. The finished surface was then covered with another
plastic sheet and then vibrated for 10 seconds, which mias based on a few trials.
During vibration, the moulding frame was held down by means of' holders provided at
the four corners of the frame.
(iv) !\ilcs vih~-a[ing for tile spccilicd ti~lic, llic plastic slicct was rcmovcd and tlic surSttcc
was once again leveled and smoothened, especially thc edges and corncrs of moulded
specimen. Thickness of the moulded specimen was checked (with straight edges).
(v) The MS moulding frame was removed carefully and the flat moulded mortar
specimen was gently placed over the corrugated ACC Sheet. Care was taken to ensure
that the flat moulded mortar specimen comcs over the valley of thc 'corrugated ACC
sheet' so that the wct or green mortar will not slide down.
(vi) After shifting the moulded mortar over the 'Corrugated ACC sheet' a PVC pipe
whose diameter equal to dimensions of the valley was rolled over the mortar in the
valleys and ridges to form the corrugation and finally finished smooth using a small
trowel. Tf necessary, small additional quantity of mortar was used to fill-up and make
up the surfaces, so as to achieve a sn~ootli corrugalcd compositc shcel of ~nliJ'or111
thickness.
(vii)The above sheets were then 'moist cured' initially for 3 days and then subjected to
'immersion curing' for the remaining 25 days to complete the 28 days of normal
curing.
'I'lic salicnl stages in Lhe casting ofcorsugalcd shccts arc shown in I:ig.3.1 I

-7.
1 I es:s conducicd
: -
(ieiierai!y roofing sheets arc espectcd to liiltill ecrtain properties such as (i) light so as not to
impose a hea1.y load on the building; (ii) good flexural strength - so as to offer a good load -
(\u~w; i~ii~~~sc~l'fo[;il) ci~rryi~ig c;ipi~ci!j,; (iii)
ductility - so as to sustain impact loading;
(il) Lzatci. tigf>tncss -so as to prevent penetratiodseepage of rain water into the building ;
is) fire resistant - so as to preventfretard ignition and spreading of fire; (vi) good thermal
properties - so as to provide a pleasant indoor clin~ate for a comfortable living.
ii!
the present study, tests were conducted to determine the following characteristics of the
col.s~igatcd sisal fibr-c shccts. ( i) ilcsi~ral strength; ( ii) irnpnct strcngth to split the corrugations;
(iii) load sccl~iircii to split thc cosri~gations ; (iv) watcr permeability tcst and watcr- absorption
test. For each combinations of mix, two sheets were cast and tested. The standards1methods
adopted for the above tests are summarized in Table.3.30. The experimental test set-ups used
for flexural, impact and splitting strengths are show11 in Figs.3.12 and the schematic views
are shown in Fig.3.13 to 3.16 respectively.
(2) I~Icxllral SL~~II~LII 'I'cst
The testing arrangement for the flexural (bending) tests are similar to that of testing of tiles
and as specified in IS: 654-1 972 [413]. Corrugated sheets are subjected to a central line load
over a simply supported span of 307.5 mm (centre-to-centre of support).Dial gauge was
mounted to measure the central deflection of the sheets. The corrugated sheets were all tested
in natural dry condition. 51ii1n (ilicli subbcr paciding t~sccl over thc support iund ~hc linc load
for the even distribution of load and to prevent slipping of specimen from the support. Load
was measured using a 50kN proving ring. Load was gradually applied till failure of the
specimen, which was noted.
(3) Impact Strenntl~ Test
1:ractured portion ol'thc spccimcn (220 s 150rnm) alicr thc flexural strcngth tcst was ilscd for
the impact test. A simple projectile impact test adopted earlier in this study was used for this
.study. The projectile was so arranged such that the impact will take place exactly on the
predetermined and marked point on the corrugated sheet i.e. on the crown of the specimen.
For each corrugated sheet, the number of blows required for the appearance1 initiation of first
crack at tlic crown point, and thc ri~~mbcr of'blows rcquil.ccl for complctc propagalio1.1 of' Lhc
crack along the crown line of the specimen, were noted. At the end of the above test the

,!,k.c:llic~: hl.c:~i,s into itto pieces. 'I'llcrc IS pro\,isio11 ill ~Iic ~~pcri~iic~ital set-LIP 10 ;ldjus~ the
i:L'lgi:t 01' t;lii li.0111 20111111 to OOmm, according to tile matcsiai being tested. For the above
icsl. the height of fali was fixed as 60mm based on a few initial trials conducted on the
~~rstig;~t~'iI fibre shects. Howcvcr, ihc weight of the metallic ball was kept unaltered
ii.e. 0.175 Kg) as in the case of impact testing of sisal fibre composites (i.e. specimens and
slabs). The height of fall and wcight of ball uscd were maintained constant through out the
abo\c icsl f'or :ill
spccimcns. I'lic impact energy per blow was compulcd in the LISLI~I manncr,
as reported earlier, which works out 0.27 Joules, for the present test. Based on the number of
b!ows for the initiation of crack and at failure, the corresponding impact energy were
calculated for the various corrugated sheets.
(4) Splitting Test
Splilting
Ccs( (i.c. the loi~l rcqi~il.td (o spli( co1.1n1giilio11s) \,V~IS co~~il~~clc~l 011 SkS ct~p~~city
universal (tension) testing machine, which is interfaced to a computerized data-logging
system. The details of the above experimental set-up etc, have already been described.
Corrugated specimen of size 120x 150mm was selected and kept in such a way that the 90mm
side is supported over the two roller supports. A point load is applied along the centre of the
sp;~ri :II~I.I
tl1c IO;I~ i~~csc:~sccl stc:~clily till split~ing occi~rrccl :11o1ig ~lic ~1x111 of'tlic corr~~g:~lioli.
'l'hc (maximum) load at the above poinl is noted, which gives thc 'splitting loail' f'or the
corrugated specimen.
(5) Water Absorption Test
Specimens of size 175 x 75 mm were kept completely immersed in water 15 - 35 T for a
period of 18hs. They were then placcd in a water bath and liept imrncrscd in watcr I'or 2
hours. At the end of the above period, the specin~ens were removed from water and any
excess water which remained on the surface of the specimens were wiped dry by a towel and
then weighed (W!). The specimens were oven - dried at 150 OC, till a constant mass is
attained. The specimens are then cooled for about lh and weighed (W2). Water absorbed by
the specimen is then found fron~ the change in wcight. since immersion. The abovc procedure
is as per IS : 59 13 - 2003 [414].
(6) Water Tightness Test
A completely dry specimen of size 150x150 mm was considered for the 'water tightness' test
(i.e. test for impermeability) of corrugated sheets. Over the above specimen a small weir to
hold was laid so as to allow ponding oS watcr, which was acconiplislicd by using (CM 1 :3 (@
W/C=0.4) or using clay. Thc spccirilcn was pill on supporls sudi that thc wcir was located

,:\$a!
iiom the suppol.ts. Water was filled carefuliy over the specimen to create ponding. The
test ii.;is generally
:L.;I~cI. \\..ill
conducted only in humid conditions (RH < 70%). Otherwise, the ponded
gc( d~.ied up imincdiatcly, cvcn before it is absorbcd by (lie spccimcn and cause
cupagc. as is thc case, di~ring a 'warm and dry' day. I-Ience, during dry season, the test is
rzcomn~ended to be conducted in a high humidity chamber, or by covering the test set-up by
a plastic slicet. Afier 24 hours of ponding the water, observe the bottom surface of the
specimen below the water pooled area was observed. If 'no free water (drips)' are seen on the
ui~ricr sitic of tl~c slicct, ~licn, the corrugated sheet is said possess a gooil walcr liglirncss.
I loucvcr, if'there arc signs ot'dampness exceeding 50"io of the water pooled area, or if water
drops are seen on the under side of the sheet, then, the corresponding corrugated sheet is said
10 possess 'poor quality' of water tightness. The above procedure as given in SICAT qi~ality
control guidelines [415], was adopted rather than the procedures given in
IS:.5913 --
tcsi.
7,003 14141, due simplicity in testing and the need to use small specimens for the
3.6 SUMMARY
In this chapter, detailed characteristics of various materials used have been presented and
results discussed. Salient physical properties of the four natural fibres chosen for preliminary
investigations, their chemical con~position in natural dry condition and after exposure in three
mediums (NaOH, saturated lime solution and fresh water), variation in tensile strength of the
above fibres before and after exposure in the above three mediums, strength characteristics
(i.e. compressive and flexural strength) of composites reinforced which 'corroded fibres'
(i.e. after exposure in the above mediums), were presented and discussed. Based on the
above, sisal fibre Wi!s
scle~tc~l Sol. Si~rther investigations. Experin~ental procedure for
workability and rheological studies; strength studies (compressive, flexure and split-tensile
strengths); impact studies on slab specimens and durability studies for sisal fibre composites
have been presented. The basis for the choosing the W/B, range for flyasli contents, fibre
contents, aspect ratios have also been highlighted. The experimental procedure for the various
tests conduc~cit on sis:rl librc rcinli)rccd corrugntcd sliccts irnd the nccd li~r various tcsts, have
been presented. Results and discussion based on the exhaustive experimental investigations
carriequt are presented in Chapter 4.

Table 3.1: Physical Properties of Cement (OPC-53 grade)
\lo.
I
/ for the tcst I re~uirements
-* .-
I Standard consistency (%) 29% /1~:403 1 (Pt4)-1988 1
I
1 Initial setting time (rnin.) 55 rnin IS4031 (Pt5)-1988 1 30 mts (rnin.)
I I I
3 / Final setting time (min.) 175 min IS 403 1 (Pt5)-1988 1 600 mts (max.)
I
I
I
Soundness 1 Imm 1 IS 4031 (Pt3)-1988 1 l Omm (max.) 1
I
--
6 / Cornpres,~ue slrengtli I@
1 I I) 3 days
ii) 7 days
1
28 MPa
IS 403 1 (I't6)-1'988
27 MPa (min.)
38 MPa 37 MPa (min.) 1
I iii) 28 days / 56.7 MPa / / 53 MPa (min.) /
Note: Sand conforming lo [he gradarion s~ipulated in I.S. speci$cationfir Sfandardsand' was prepared in
(he Ic~horalory nnd ri.red/cir delermiuir7g [he compressive sirenglh of cement.
'I'ablc 3.2: I'roperties of 1tii.r~ Lignite *
1.
2.
Moisture
Ash
50-55 %
3-13 %
3. - Volatile matter -- 20-25 %-
1
-
4. I:iscd carbon
17-25 %
5. , Calorific value (kcalikg) , 2600-2800
Note: (*)- As reported by Manoharan j3.521
Table 3.3: Physical Properties of Flyash

'
Table 3.4: Chemical Characteristics of Flyash
1- ---
I Si ' Chcmicsl Composition / Valuc 1 lS:3812 1
i
1 No.-,
('XI by wt.) rcquircrnc~its
I Loss 01 ignltlon
2 Silica as Si0:
35 87 35 % (min)
3 Iron as Fez O3 4.00
4. 1 Alumina as AL2 O3 34 14
5. / Calc~um as CaO 14.25
- 6 Magnes~unl as MgO
1 7 1
I
3 64 5 % (max)
--
Suipll;~lc -- ;IS SO, --- 3.40 .-.-
- - 2.75 (111ax)
X. Sodit1111 as No --
20 0.90
I .S (YO
I--
9. I Polassiurn as K2 0 j 0.06
1.5 %
10. Chloride
I 1. 1 . Silica+alumina+iron
70 % (min)
Note: I. Flj~a.rh isporn a lignife source located in Neyveli, Soulh India.
2. IS: 3812 - 1961, "Speci~cationjbrjlyash use as pozzolana and
adrnix/ure. (Firs/ Rcvi.ciot7)
i 74 12 'M, (rnax) 1
I
Table 3.5: Particle Size Distribution of Flyash
Particle size in (rnrn)
1 1 .I80
Perccntagc finer 100
1.180
100
0.300 0.150
96 90
0.075
85
1 I
0.045 0.020 ' 0.0 10
75 54 32
I
Table 3.6: Comparison of Particle Size Distributions of Other
Indian Flyashes with the Flyash Used
S1.
No.
1.
2.
3.
4.
Cliaractcristics
An reported by
Sharma [3.2]
Present
* *
study
Percentage finer than i 54-93 80-87
75pm in size
Percentage finer than 32-79 65-75
45pm in size
I'crccnlagc lincr than 20-90 1 41-54
20pm in size
Percentage finer than
46-96
23-32
-
1 Opm in size I
Note: (*) - Samples were collected from I0 (ten) thermal power stations
located mostly in northern India and are coal -based flyahes .
(**)- It is lignite- based flyash and it is not covered in the studies
carricd by Sliarnia [354]

T:tbIc 3.7: Izincmess and Lime Reiictivity of Flyash
No.
i 1. Fineness (mL/kg)
I
440
as per-^^ 3812
320 (Grade I)
I
I
I
I
i.imc reactivity (MPn)
I
/ 250(GradeII)
7 3 4 0 (CrradeI)
hlo I e:
fi).Grade 1 -for incorporation in cement mortar and cot-rcrete in lime Poz-.oiann
r~i~l~rre undjbr the rnunztjircfure of Portlrmd I'ozzolanu cemenl.
(ii) Grade /I- for incorporation in cement morlar and concrete and in lime Po-.zolana
rnixture .
Table 3.8: pH Values of Flyash - Cement Blends
Note; I. pH was determined using a digilalpH melre
2. Mnke : El lr7.strun~en~.s Parwrioo. HP; Model;
lOIE; Accuracy = 0.01

, - -s-,; -,
7':lhlc 3.9 (21):
1 No. 1
PI~ssic:~l I'roperties of Firlc Aggrcgatc
I---
. -
vdr-i
description
1 1 Specific gravity 1 2 48
3'0te: Procedure 15 based on IS 383 - 1997 13741
Tablc 3,9(b): Rcsults of Sieve Analysis of Fine Aggrcgatc
IS Sieve Wt. Cumulative Percentage Percentage 1
percentage passing passing as per j
retained ('YO) 133383: 3997
("/.I (for Zone 11)

Table 3.10: Phy~ical
- - 7 --
,\I. l7,I,rc- pzzi* Fi 1) rc
' . 1 i 1 (mm) I
, I I
I
i 1 I i
I 1 j Coir
I
I 2. i Sisal
kkrC!
Prnl\~sti~E ~-\f V E ~ ~ ~ ~ ~jl;;~~ :
'I'cnhilc
i~:loogatioi~
dis~netrr 1 strength ((%)
(mm) (~lmrn*)
I
S1)orific
gravity
Table 3.1 1: Salient Chemical Composition of Various Natural Fibres
I
SI. I Fibre
, No. I
1. Coir
2.
Sisal
31.1
26
33.2
38.2
1 Lignin
(Oh)
26.0 1
I 3
.li~te
22 7
33.4
4.
Hibiscus
2 5
28
Nole (I) The composilrons are % by wl of dry andpowderedjbre smnplc.
(2) Only the salient chemical compositions are indicafed

Table 3.12 (a) : Overview of Durability of Natural Fibres Investigated
I- --
I hi. Fihrc type , Aging/euposurc contlitions Rcfcrcnccl(s) 1
I
376
piifquero) 1 :
23 1
207
1 5 Date palm 260
I
I
Note:
grass
(i) Description of codes in aging/exposure condilions are us follows:
I- Alkaline medium (continuouslalternaie wetting &drying under room/elevated
Icmperalrrrc)
I
7 Hemp 274
8 Jute * a 9
I
/ 244,274,206,9
I 1
I
I
9 Musamba
297
10 , Remie
---
Sisal
Plantam
13 1 Water reed , e
* I
e
s
o
, o
0
---
a
2- Alierti~lc ~velii~ig (111d i/tyjllfi; 3- 7iil) MJ(I/C~ (over un/:)'i/ig i~eriods);
3- Cemcnl suiurc~ted >va(cr; 5- Sec~wuler; 6- NISOj sollilio17 (1%);
7- One year old mortar and water cured; 8- One year old mortar (air-cured);
9- NazSOl solution (10%); 10- Allernate freezer and waier curing;
11- Alternate elevated and normal water temperature.
(id Oilerion lo evu/rin/e /lie diiruhi/i/~~ q[fihrc.s qper e.Tj)o.ciire in /he vnrioiis iesi cotiiiilions call he
sr~mmori;ed trs: Tc~nile .s/rc~ri~llr; ('i~oti,ycs ill /oig/i1/dio1~1c/c1./ wci

i'able 3.12 (h) : Overvie\ of Ilurability of Natural Fibre Composites Investigated
!Vote:
(G t7-Flexurc~l sire~~giii; 7: 7'0liglil~~'.s.s; L- I.'I.~IIC/~ ( I I I ~ Uelgluli Io~itl rtriios: S- (C'onipre.s.siot~) Sheur;
1 - Impact sirength
(iij Description of codes for aginglexposure conditions are as under:
I-Tap water; 2-Alkaline medium; 3- outdoor environment; 4- Alternate wetting & dving;
5- Na2S0, soiu~ion (10%); 6-Alternate elevated and near zero
temperature; 7-Alternate elevated and curing in normal water temperature; 8 -Alternate freezer
and curing in normal Nater temperature: 9- Cyclicjeeze-thaw ;
iO-Accclernio. carhorlniion nnd 11- No/ u~~ier. .soak lext (ASTM C 1\85).

I :tj,lc 3.1 3: O\ cr-1 icw of 1111p:lct licxisf:~ricc VTci~s[~rc~llcnt for IJibrc 12cinforccd
Sl.\;o.
I
* - --t
Composites
Test Method
-
Type of Fibre
Reference
I 1 Drop We~ght Steel 383 - 388,398 - 404,
1
I
j Polypropylene
I
/ I:lcplanl gr;lss 207
392 405
I Jutc 205,234,206
Coir 234, 206, 404,21 1,
283
Sisal 283,210
I 1 Palm-Kernel 395
Malva 265
' 2
I
' ;
I -)
L
1
t
, 5
Instrumented impact
Lxplosive irnpdct
Projectile impact (lo~vlhigh
velocity)
(a) Pendill~~ln (CharpyiIzod)
impact
(b) Modified pendulum
impact (insti urncntcd
charpy)
Steel
P~ol>p~opvlene
1'01jpropyle11e
Steel
Akwara
S tee1
Steel
381
189 - 391 I
- 393 7
206,404
23 1
396
I

- -
51. Fibre Sodium hjdroxide ' Saturated lime 1 Fresh water i
Kotc.
11) \I - lien~icell~ilo,se.. C - Cel/iilo.se; L -- L1gt7111
iiil Figures wifhin brackets indicuie loss in the respective chemicul composiiion
uber 60 dnys o,folterr~ate wetting und drying cycles in the respective mediums.
Table 3.15: Chemical Composition of Various Natural Fibres After Exposure in
Various Mcdiums (continuous imrncrsion- 6Odilys)
- . - - . --~. -. ..
I . i Sodium hydrositlc i t 1 1
-.
-1
--
lJrcsh waicr
No. ) type Chemical composition (96)
H C L H C L H C L
1 9.7 23.8 15.1 24.0 8.8 18.9 13.4 10.4 10.8
2
3
I
Uotc:
(Q H - Ne111iccl11iio.se; C - Ccl1~1lo.re; - L,ipiin
(ii) Figures within brackets indicate loss in the respective chemical composition
after 60days ofcontinuous immersion in the respective mediums.

'I'ahlc 3.16: 'Iensile Strength of Various Yatural Fibres After 60 days of Alternate
Wetting and Drying
Coir
Sisal
Tcnsile strength (N/mrn2) 1
Natural dry 1 Alternate wetting i~nd dying in
condition
I5 -327
hydroxitlc
7.6 -i50.5
I
limc water
3 -143.7 1 3 - 178.9
Hibiscus 18 -180
Cannebinus 1
I
10 / (*)
!
I
3-37 1
I
I
Table 3.17: Tensile Strength of Various Natural Fibres After 60 Days of Continuous
Immersion
1 No.
bi-
-
Fibre
type
Coir
Natural dry
condition
Sisal 31 -221 23 - 38 4.5-18 1 16-90
Jute j 29-21 1 5-22 1 2-12 15-15 1
Hibiscus
Cannebinus
15 - 327
18 -180
Note:
(9 (*j - indicates that the fibresfailed to take any load
.----.--A-
'I'cnsilc strength (Nlmm )
Alternate wetting and drying in
Sodium
hydroxide
40 -109
1-22
Saturated
lime
22.6 - 64
7- 18
(ii) The range of values indicated correspond to the lowest and the highest tensile
.s/t.en,q/l7 c![ccrch b~pc//ihre ~jicr /JIB d~rohili!)~ s17tdie.~ .
Fresh
water
46.4 -144.4

I
I
Table 3.18: Compressive Strength of Fibre Reinforced Mortar (1:3)
(Corroc(cd,/ihr~~,r ~~l(l,fjhr~~ ill 11~fllra1 (Ir) colf(/i/io~i)
--.- , - -- -- _ - _-_ _ _--- -_-- --
51. 1 C ompressi\ c strength (Nlmrn
2- ) - ----1
I
0 . Fibre type ' I I I
!-
I
Water
+-----,
Ca(OH)* KaOH
2 1
, 1 1 2 I 1
!
1 I Coir i561169
I
75 118
14.8
2
16.6
Natural dry
condition
17.3
17 8
11 3
I
Canneb~nus
88 1
j
Note:
(i) ('oinj~~.~'~.~ive .S/I.L'I~,~!/I ufccin~rol n~ix (1:3), rvirhou!Jhrc.r = 27.0 ~V/rn~n'
(iij (I)-- inciicaies irl/erno/e wetling and drying and f2j - indicules conri~i~rom
imrnersiot7 it [he respective mediums.
Table 3.19: Flexural Strength of Fibre Reinforced Mortar (1:3)
S1. I Fibre type
NO. i
Flexural Strength ( ~/rnrn~)
1
2
i
/
/
Coir 1.1
Sisal
1
1.7
, Cannebinus
I
I
water Ca(0H)z NaOH Natural dry
condition
1 2 1 2 1 1 2
3.9 I .O
4.7
i
'
2s5 2.1
4.1 1.1 2.9 1 1.2 3.2 5.8
3.3
1.1 3.0 1.7 I 4.0 4 3
3.4 1.8 1.8 1.8 2.0 3.5
I
Note:
(i) Flexural strength of control mix (1:3), without fibres = 6.9 iWmrn2
(i4 (I) - indicates alternate wetting and drying and (2) - indlcares conlinlious
ilnnler.vion in /he raspeciive ~~iediroii.~.

7':tit)lc 3.20: Cornpiirison of Strength- loss of Fibre Reinforced Mortar (1:3)
I
1
..
S1.
No.
- - CC- - - -,-
I
.
-- --
Maximurn rctiuctior~ in
type 1 Compressive strength 1 Flexural strength
I I ("/")
1 Coir 56.7 [CE~(OI-I)~]
I
1 Sisal 1
I
I
(%)
75.8 (Ii20)
Note: The sfrength - 1o.s.s are hrr.reii on the s/rengih.r c!J'corre.spondirig, fibre ur~iier
t~ururul dt:y cotiditiut~

'Fable 3.21: impact Energy Absorbed by Slab Specimens
(Reference and Four Natural Fibre - Reinforced)
Fibre
cor~tc~lt
(I%, Ity wt.of
cr~~~rn t)
Impact energy absorbed by natural fibre reinforced
slilh snccimens (in .Joules)
A
13 c
Initial / Final initial liin;11 l~litial Iiniil
I
I 1
i
Sisal
Note A,B,C corresponds to the fibre length oj2Omm, 30mm & 40mm respectively ,used ro reinforce slabs

pL
Table 3.23: Details of Mix Proportion of Reference Mortars
- -
S1. Rli, - ~'clncnt ' Sarnd W/C ' I:low 1
No. ratio (W) (gm) ratio value
("0 >
1. 1 :3 150 540 0.64 111.5
---
2.
3.
1 :4
1 :5
150
150
-
600
750
Note: Tl~c ~rhove proporfior~ were u.redfor studying lhc ~~ot-kability; jor rlzeoloyical
studies, especially to study the effect ofaspect rario andfibre conrent.
.-
0.67
071
11 1.5
111.5 I

Table 3.25 (a): Mixes Considered for Workability and Rheological Stud of Sisal Fibre
Reinforced Mortar (1:3; r = 200)
I S1. I Fibre I
Mix constituents (OPC + flyash+ fibre content) for flyash contents of
Note:
(I) The quantltres mdicared above are for a mortar cube of size 70 7 x 70 7 x 70 7mn1 and they ore in 'gm
(11) The sand confenf = 50 grn (same for all mrves gradafron of sand IS ma~nrained consinat)
(211) Total no of mlxes consrdered = 42
(IV) The above stud) u crvriedozrt ar constant aspeci ratio 'r' ofsisalfibre = 200

'I':iP,lc 3.20: \V/l3 l

---!--_
1
'rable 3.28: Testing Standards Adopted for Various Strength Studies
----
$1. Type of test Measured quantity Standardladopted I
1.-
,
I
No. 1
. ~ -.-.-+-.-__---r
I . 'ompression test (broken piecc of I Conlpressive strength IS 403 1 (Pt8)
beam specimen)
(MPa)
I 1 Flexural test (beam specimen) Flexural strength , IS 4031 (Pt8) ,
i
I
,-1
(MPa)
Split tensile strenglh
(MPa
, Impact strength (J)
strengtll
3. Split Icnsile test (brokcn piccc of
beam strength)
4. Impact test (slab specimen)
I 5 i:lcsor;~l lcsl (Four poini loading) I~luxunl
As per 1-~unnant"
No standard*'
No standard*.'
Note:
(*I)
- The split tensile testing procedure adopted as given by Hannot and discussed
in the text book of Concrete Technology, under the titie of "indirect tensile
test for concrete- details given in Appendix-R
(*2) - l'l~o,jcc~ilc i~npriclcsl scl1ip rrtloplcd in lliis sltitly lo cval~~;~lc lllc i~ilpncl of'
low strength concrete and mortar specimens, is yet to be standardized.
(*3) - Flexural setup was exclusively fabricated and used in the INSTRON GTM-
to determine the flexural strength . The above values are compared with the
flexural strengths obtained by the Indian standard proc3edures for testing
of clay tiles ilsing 50kN capacity testing ~nacliine.

Table 3.29: Quantity of Materials Used for Casting Corrugated Sheets
(Size: 250 x 500 x 6mm; 1:3)
.-. - .- .-. -. ----
m~ibr~ibre I Mix constituents (OPC ; flyash; flyash; fibre content W/C ) for flyash contests of
-.
-- .- .
No. content
0 O h
10%
20%
40 '/a
1
2
3
4
I ("/o)
0.00
0.25
0.50
0.75
928,54,0.0.0.4 1
928.54,0,2.32.0.44
928.54,0:4 64.046
928.54,0.6.96.0.48
928.54,0,9 28.0.50
928.54,0,13 92.0.53
835.68,7.2.0,0.51
835.68,73.2.2.32,0.53
835.68,73.2.4.64,0.54
835.65,73.2.6.96,0.56
835.65,73.2.9.28,0.58
85.65,73.2.1.92,0.54 -
Note:
(IJ For all rnlxes sand cot7rer~t ; 2 34 kg
(2) Quantity of nzaferluls lndrculed are 1t7 gnzs ', for cat[ of one sheer
742.83,142 42,0,0.62
742.83,142 42,2.32,0.63
742.83,142.42,9.G4,0.65-81-
648 98.2219.62,0,0.77
648.98.2219.62,2.32,0.79 '
742.83,142 42.6.96,0.66 648 98.2219.62,6.96,0.83 '
5 1 1 742.83,14242,9.2,0.68
.- 00
648 08.2219.62,9.78.0.84
6 ( 1.50
742.83,142.42,13.92.0.70 648.98.2219.62,13.92,0.87- ----A
7 1 2.00 ~928.54,0,18.57.0.53 835.65,73.2.18.57,0.60 742.83,142.42,18.57.0.71 648 98.2219.62,18.57,0.89 -- :

Table 3.30: Standards Adopted for Testing of Corrugated Sheets
S1. j Type of test Standard
Note:
(*I)
-These two tests are conducted to know the failure of corrugated portion only i.e.
(i) energy rccl~~il-cd to break lhc corr~iyitiions imd
(ii) Load ~.cq~~ircd (o split tile corrugations.

Fig.3.1 (a) Stages in the Processing of Coir Fibres from Plant to Ready to - use Form
Fig.3.1 (b): Stages in the Processing of Sisal Fibres from Plant to Ready to - use Form

Fig.3.1 (c): Stages in the Processing of Hybiscus Cannebinus Fibres from
Plant to Ready to - use Form
Fig. 3.1 (d): Stages in the Processing of Jute Fibres from Plant to Ready to - use Form

Sisal Fibre Specimen
Fig.3.3 (a) : A View of the Experimental Set-up for Fibre Tension Test
5mm
T
5
60mm
- v
5mrn
-
2
(1) Fibre Specimen
(2) Thick Sheet
(3) Window Split
(4) Cutted edges of
Sheet
(5) Glued the fibre on
to the sheet
Fig. 3.3 (b) : Details of Sisal Fibre Specimen

(1) Fibre specimen
(2) Lower fibre fixture
(3) Upper fibre fixture
(4) Levers for fixing fibre
(5) Upper machine
cross - head
(6) Load cell (5kN)
(7) LVDT (50mm)
(8) Fixed flatform
(9) Treaded guiders to
upper machine cross head
Fig. 3.3 (c) : Schematic View of Fibre Tension Testing Machine

I Strain (%) I
(a) For Coir Fibre
I Strain (%)
I
i -
(b) For Sisal Fibre
.- -
Fig 3.4 (a)-@) : Stress Vs Strain of Coir and Sisal Fibres
(In Natural Dry Condition)

1 1.5
Strain (%)
(c) Hybiscus Cannebinus
- - - - -- - - --A
0 0.5 1 1.5 2 2.5 3
Strain (%)
(d) For Jute Fibre
I
Fig 3.4 (c)-(d) : Stress Vs Strain of Hybiscus Cannebinus and Jute Fibres
(In Natural Dry Condition)

Fig. 3.5 (a) : Samples of Powdered Fibres for Detemining
Chemical -Composition
Natural Dry
Condition
NaOH Solution
Fresh Water
:a(ON), Solution
Fig. 3.5 (b) : Fibres Before and After Immersion in the Various Mediums

(a) A View of Flow Table Test
(b) A View of Flow Table with Cement Composite Sample
Fig. 3.6 : Test Set-up for Studying the Workability of Composites

(a) A View of Direct Shear Test Set-Up
(b) Shear BOX Used
(c) Sizes of Shear Boxes Used
Fig. 3.7 : Test Set-Up Used for Studying the Rheology of Composites

(a) A View of Flexural Testing Machine for Prism Specimens
(b) Test Set -Up for Compressive
Strength of Mortar
(c) Test Set -Up for Split- Tensile
Strength of Mortar
Fig. 3.8 : Prism Specimens for Determining the Various Strength Characteristics

(a) A View sf Prog'ecrtjlle Impact set-up
a- Sphere ball of 475g ;
b- Chute for guiding ball;
c- Iron stand for supporting
chute
d- lron stand for supporting
mortar slab
e- Mortar slab specimen of size 300 x 300 x18 mm
(b) A Schematic View of Test Set-Up
Fig. 3.9 : Experimental Set-Up Details of Impact Test on Mortar Slabs

Shown in (b)
&s>"L-
(a) Data Acquisition System
(b)Experimental Set-Up
Fig. 3.10 : A View of Experimental Set-up for Flexure Test of Mortar Slab
(with Data Acquisition system)

(a) Spreading the Mortar
(b) Dragging the Spread Mortar Over
eor~ugated MOUI~
(c) Creating and Finishing the
Cormgations
(d) Cast Corrugated Sheet in Wet State
(e) Finished Product with Base Frame
Fig. 3.11 : Stages of Casting Corrugated Sheets

(a) Flexural Strength
(b) Impact Strength
(c) Splitting of Corrugation
Test
(d) Water Tightness Test
Fig. 3.12 : Experimental Test Set-up for Various Strength Tests on
Sisal Fibre Corrugated Sheets

Front View
Side View
1- Span ( 307.5 mm); 2- Corrugated sheet (size 250 x 500 x 6mm); 3- Circular pipe (015mm) for applying
pointed line load; 4 - Proving ring (5M capacity); 5- Uppper machine cross head; 6 -'I' section to give
rlgld support to sheet, 7- Roller support (040mm); 8 -Swith control; 9 -Wheel for selecting loading rate,
10 - Load~ng unit
(a) Flexural Testing Machine with Corrugated Sheet
I-+-+-
1 ) I
--------)
i
--4-
1
i
1
1
3
I
i
--L ------,v-rT-,-F-__L-- A--
I 1
1 2 1
(1)-(1) -Support line; (2)-(2) -Load line; (AB) and
(EF) -Ridge lines; (CD)- Valley line
(b) Corrugated sheet with marking of
loading and support lines
+ 35nmm *
(c) Size of Corrugated Sheet
Fig. 3.13 : Schematic View of Test Set-up for Flexural Strength of Corrugated Sheet

XI-
CPC - XX
1- Projectile impact tester ; 2- Sphere ball of 450g; 3- Single corrugated specimen ( 220 x 150 mm);
4 - Sand filling as cushion to sphere ball while impacting ; 5 -Concrete pedestal for supporting sheet ; 6 - Compacted
dry sand bed ; 7 -Point of impact ; L = Span of Cormgation - 220 rnm ; h- height of fall (mm)
Fig. 3.14 : Schematic View of Test Set- up for Impact Strength of Corrugartion
(a) Front View
(b) Side View
18ingle sisal corrugated specimen (120 x 150 mm) ; 2- Lower (I) beam to hold the
corrugation; 3- Upper (I) beam to apply load ; 4- Upper machine cross head ; 5- Load cell
Fig. 3.15 : Schematic View of Test Set-up for Splitting Load of Corrugation

+ 150mm j
thickness 20mm
Pig. 3.16 : Schematic View of Test Set-up for Water - Tightness of Sisal Fibre
Corrugated Sheet (Pooling area = 150 x 150 mm)

CHAPTER 4
RESULTS AND DISCUSSION
In this chapter, the results of the comprehensive experimental investigations on the various
characteristics of sisal fibre cement mortarlfly ash-cement mortar composites, namely, on
the tvorkability and rheological characteristics, strength (including slab specimens) and
duiab~l~ty cl~aractcristics of the composite slabs, ha\*c bccn pl-cscntcd and d~scussed
Comparative performance of corrugated sisal fibre sheets with that of conventional sheets,
have also been presented and discussed.
1.2 RESIJLTS AND DISCUSSION
4.2.1 M1;ltcr Al~sorption of Sis:~l Fi11r.c~
From the rate of water absorption data for sisal fibres, shown in Fig. 3.2, following
inferences are drawn.
(i)
(ii)
(iii)
The rate of water absorption is about 50 - 53% for every 5 minutes, upto
the first 10 minutes.
I3cyond first 10 minutcs, incrcasc in thc rate of watcr absorption docsn't cxcccd
10% for each increnlent of 10 minutes i~plo 1 Ilr and each additional 1 hour,
upto 6 hr.
After 6 hours and till the end of 72 hours, the rate of water absorption is stable,
which means that saturation level has reached at the end of 6 hours and that the
~l~aximum water absorption is aboi~t 160%.
Frorn the above, it can be stated that the water absorption of sisal fibres during the first ten
minutes should be considered and proper mixing procedure evolved so that adverse effects
of such a behaviour may be minimized. Moreover, the above fact should be considered in
arriving at the net water available in the mix, which has a bearing on the strength and
durability levels that can be achieved by the composite.
It is found that the ~llaxinlun~ water absorbed by the sisal fibres, in this study, is higher
than the reported value for Brazilian fibres [Savas , CCC, 19991.

42.2 Dimensional Stability
'i'hc icsults of the 'dimensional stability' of sis~tl fihrcs nfier two cycles of 'alternate
\t.t.tting and ilrj'ing' are give11 in Table 4.1 and the variation in water absorption with
~cspcci tu tlic number of'days and !'or tlic two cyclcs considcrcd, is show11 in I:ig 4.1. 1:t-om
the above rcsults. following inferences have been drawn: (i) There is no change in the
ciiameter of the fibre and hence in the volume of the fibre; (ii) The rate of water absorption
during he first 24 hours is very high, when compared to the rest of the period considered;
(iii)
Afier 24 hours, the rate of increase in water absorption is substantial and gets
siabilizcci at about 129.5'1/; Ihr tlic remaining period (i.c. l2duys) during the lirst cycle in
the 'alternate wetting and drying' of the fibres; (iv) Similar phenomenon is observed
during the second cycle. However, there is reduction in water absorption of the fibres,
which is obvious as saturation capacity would have been reached at the end of first cycle
itself; (v) Water retained afier 10 hours of drying is found to vary between 1-2 % (over the
two cycles considcrcd). This shows that the water retention capacity, especially, when
sisal librcs are subjected to altcrnatc wetting and drying cyclcs, is ncgligiblc. l'his cxplains
the negligible changeino change in the diameter of sisal fibres, during the above cyclic
treatment. From the above behaviour, the only point to be borne in mind, from practical
consideration is the higher rate of water absorption of sisal fibres, especially, within the
first 10-20 minutes of its contact with water and the consequent implication in mix
proporlion ol'thc composilc.
4.2.3 Workability of Sisal Fibre Mortar and Composites
(A) Cement Mortar Composites (at various aspect ratios)
Thc flow valucs or' sisal fibrc ccn1c17t mortar composites (1 :3, W/C = 0.65; 1 :4, WIC =
0.67; 15, WIC = 0.71) for aspect ratios (r) ranging from 0-300, are prcsentcd in 7'ablcs 4.2
(a) to 4.2 (c). The variation in the flow values (%) with respect to fibre contents (%),
i.e. 'flow curves' for the range of aspect ratios considered are shown in Figs.4.2 (a) to
4.2 (c), for 1:3, 1:4, 1:5, respectively. From the analysis of the above results following
salient inferciices arc drawn:
f1) 1 :3 Mortar Coinposites
(i) Flow values of mortar composites (1:3) are generally less than that of the
reference mortar (i.e. without sisal fibre and flyash). The reduction in flow
values reduces with increase in sisal fibre content in the composites. This

(ii)
(iii)
proves that thc 'mobility' of' thc mix (mortar) is itnpaircd by tlic
additioniincorporation of sisai fibres.
The above pheno~nenon is found to be independent of the range of aspect ratios
considered. However, higher the aspect ratio in the mix (1:3), higher is the
reduction in the flow value of the composites. This shows that there is a
cicsirahlc nspcct ratio, beyond whicli the 'mobility' of' ~lic mix is drastically
affected and may not be desirable from practical considerations.
Reduction in flow value is the highest (i.e. about 73%) at the highest fibre
content (i.e. 2.0%), when compared to the flow value of 'reference mortar'
( i.e.without fibre; 1 :3).
Q] I :4 and 1 :5 Mortar C'omlx-
(iv) Influence of'the 'aspect ratio' and 'fibre content' on the flow bcliavio~u of 1 :4
and 1:5 mortar composites are similar to that of 1:3 composites. However,
reduction in flow values for the 'highest aspect ratio' and the 'highest fibre
content' for 1 :4 and 1 :5 composites are nearly half (i.e. about 35-38%) of 1 :3
composites. The above phenomenon may be attributed to : (a) increase in the
watcr availability in the mix duc to increase in WIC for 1 :4 and 1 :5 over 1 :3
(for a constant flow value) and, (b) due to higher sand content in 1 :4 and 1 :5
over 1 :3. The cun~ulativeffect of the above two is the increase in the mobility
of the mix, in spite of the presence of the sisal fibres, as the fibres are not
confined between the particles in the mix, thereby reducing the chance of
'interloclting' of fibres and 'balling cff'ect' of tllc [nix.
13) Influence of Aspect Ratio and Fibre Content
The influence of the aspect ratio and fibre contents on the flow values as stated above are
also brought out in the Figs.4.2 (a) to 4.2 (c), as evident from increase in the slope of the
flow curves, with increase in richness of the mortar mix and amongst flow curves for a
particular mix.
In case, it is intended to restrict or colitain the reduction in flow values of the composite
(1::) and achieve at least a flow value of 50% of the reference mortar (1:3), then, the
maximum fibre content that can be used in the composite is: (a) upto 1.0%, for the aspect
ratios less than 65 and (b) upto a maximum of 0.5%, for the aspect ratios greater than 65.
011 the other hand, the entire range of fibre contents and aspect ratios considered in this
study can be used in the 1:4 and 1 :5 conlposites, without reduction in thc 'mobility' of the
composite beyond 50% of that of the 'reference mortar'.

k!fi~c~:.cssloll~cl~l~i~~llslli~~s
L,i:lt.nr regression relationships for 1 :3 cement mortar composites between flow values (y)
nilJ fibre contents (x) have also been obtained. for the range of aspect ratios considered,
Lr,ilicil :ire summarized below:
(i) r = 0-35 : y = (-) 34.048 x +12 1.5 (R~ =0.80) ... (4.1a)
(ii) r = 25-65 : y = (-) 35.589 x -1-1 17.35 (li' =O.X8) ... (4.1 h)
(iii) r=65-135 :y=(-)40.498~+112.44(~'=0.81) ... (4.1~)
(iv)
r = 135-200 : y = (-) 40.943 x t107.52 (R~ =0.86) ... (4.1d)
(v) r = 200-300 : y = (-) 41.765 x +104.0 (11~ =0.88) ... (4.1~)
Siniilar regression relationships have been obtained for 1 :4 and 1 :5 cement mortar
co~i~posi~cs, which i11.c s~l~ii~n;~ri;.'cd in Appcniiis (.'-8. It is sccn that Iiiglicr correlation
cocilicients (li')
arc obtaincd for rcgscssio~-i relationships of' 1:;
for other composites considered, indicating better consistency!confidence
mortar co~npositcs than
in the results
obtained. The abovc regression relationships can be used to predict the flow values and
vice - versa, over the range of aspect ratios, considered.
(U) Fly as11 - Centeirt Mortrrr a d Con~pasites (ut rr colrstrrnt rl.cpecf rrltio, r = 200)
The flow characteristics of fly ash-cement mortar (13) are presented in Table 4.3. Flow
characteristics of cement mortar and fly ash-cement mortar composites (1 :3) at a constant
aspect ratio (r = 200) and for various fibre contents (0.25 - 2.0%) are presented in
Tablc 4.4 and 4.5, rcspectivcly. 111 the abovc Tables, WID ratios required to obtain various
(low vall~cs ill [llc rltngc 50 -17-0 (ill steps of' 10) Il;~vc bcc~~ cxl~csinlcn~:~lly oh{aincc[ and
the results presented.
(1) Flyash Cement Mortar - 1:3
Comparing the WIB ratios of flyash-cement mortar for the various flow values (Table 4.3)
with that of reference mortar, i.e. cement mortar (fly ash content = 0%; fibre content =
(I1%)) Ibllowing infcrcnccs arc drawn:
(i)
(ii)
WIB ratio gently increases with increase in the required flow values, when the
fly ash content = 0% in the mortar, i.e, for the 'reference' mortar.
As the fly as11 conte~ll increases in the mix, WIB ratio required to
achievelobtain a particular flow value, also increases but gently. The above
phenomenon is foulid to be indepcndcnt of thc range of flov,~ values considered.

(iii)
WI13 ratio required to achieve a particular flow value is found (o reach the
maximum, when tile flyash content is also maximum (i.e.7096) in the mix. The
above phenomenon is also found to be independent of the range of flow values
considered. Moreover, the above maximum %'/B ratios are 0.23 - 0.25 higher
than the WIB ratio of reference mortar at the corresponding flow values, and it
is li>ilnd to be inticpcndciit of the rango 01' \low valucs. This shows that the
additional cicmand Ibr water is primarily d ~ to ~ the c prcscncc of flyash in tlic
mix and that the increase in the WIB ratio at the maximum flyash content
(i.e.@70%) is about 37- 4S0/' with an average of about 42% over the WIB ratio
at corresponding flow values of reference mortar and for the range of flow
values considered.
(2) Cement Mortar Cornpositcs - 1 :3
Incorporation of sisal fibres in the reference cement mortar (1 :3) influences the WIB ratios
required to achieve a desired flow value, as evident from the results given in Table 4.4.
Comparing the WIB ratio of 'reference mortar' with that of sisal fibre cement mortar
composites, and based on critical analysis, following inferences are summarized:
(i)
(ii)
(iii)
'l'lic~.c is a gcnllc i~icl.casc in t11c WIL3 mlio rcquircd to achicvc a Ilow vill~lc, due to
increase in fibre content. The above behaviour is found to be independent flow
values considered.
WB ratio is found to be maximum, when the fibre content in the cement mortar
con~posite is maximum, for the range of flow values considered. Highest WIB
ratio oI'0.77 is requireti Ibs the composite. when thc dcsirccl Ilow valuc is also the
maximum (= 120).
The above phenomenon shows that the increase in W/B is primarily due to
incorporation of fibres in cement mortar a ~ directly ~ d related to the fibre content in
the composite. However, the maximuni WIB ratio required for a desired flow
value at niaxinium libre contcnt (i.e.2.0(!4,) is found to be 0.1 1-0.12 Iiigllcr tIia1-1 thc
WIB ratio at corresponding flow values of reference mortar (1 :3, without fibre and
without fly ash) and it is found to be independent of the range of flow values
considered. In terms of percentage increase in the maximum WIB ratio at
maximum fibre content, it is about 19-22%) with an average of 17% over the W/B
ratio of reference mortar, at corresponding flow values.

) 1,I.loreover. it can been seen that the WIB ratio required for a flow value, is
'ii~scnsitivc' at very low sisal iibrc contcnts in the ccmcnt mortar compositcs, i.c.
upto 0.50%. Only beyond the above fibre content, WIB ratio becomes 'sensitive'
in the composite. This is also found to independent of the range of flow values
considered.
(:omparing the de~nand for water, in tcrnis of the W!L3 ratio due lo the incorporation of fly
;is11 and sisal fibres indcpendcntly in the cement mortar, ('l'ablts 4.3 and 4.4) it is sccn that
the demand for water is generally found to be higher due to the incorporation of fly ash.
in ihct. the increase in the Win ratio at corresponding flow valucs due to incorporation of
llyash is nearly two times the increase in WIB ratio due to the incorporation of sisal
fibres. alone under identical conditions and the range of the parameters considered in
this s1~1cIy.
(3) Flyash - Cement Mortar Composires - 1 :3
The cumulative effect on the demand for water, in the flyash cement - mortar composite
(12) in terms of W/B ratio, due to the incorporation of fly ash and sisal fibres is
summarized in Table 4.5. Based on the critical analysis of the above results, following
ohsc~.vatio~is I iiil'cscnccs arc drawn:
ti)
(ii)
(iii)
'There is a gentle increase in the W/B ratio, due to increase in fibre contcnt and at a
fly ash content of 10%. The above behaviour is found to be independent of the
range of flow values considered, for the above flyash content.
The above trend in W/B ratio, is found valid for various fly ash contents and upto
the maximum fly as11 content considcred i.c. 70%, in tlic coniposilc.
However, the WIB ratio for a desired flow value is found to be higher than the
case, wherein, either sisal fibres or fly ash alone is incorporated in the mortar mix
(1 :3). In other words, there is a cumulative demand for additional water due to the
presence of fly ash and sisal fibres in the mortar mix. Moreover, WIB ratio
required to achieve a particular flow value is niaxiriium wlien the fibre content and
the flyash content in the mortar colnposite are maximum, with in the respective
ranges considered. The actual increase in the WIB ratio, under the above
conditions is nearly constant and lies in thc narrow range of 0.26-0.28. However,
the percentage increase in the WIB ratio, under the above conditions is in the
range of 40-53%, wit11 an average of about 47%, with respect to the WE3 ratio at
corresponding flow valucs or rcfcrcncc mortar ( i .c. 1 :3; libre = flyasli = 0%)). It is

also seen that the increase in the above W/B ratio is cclual to thc cuniulative
j1ict.ense in the demand for water due to the incorporation of flyash and sisal.
fibres. lbr identical valuc ol'thc paromclcrs consicicrcd in this study.
(4) Cement / Cementitious Mortar Composites - 1 :4
I:lo\v characteristics of cenientitious mortar and composites (1 :4: t. = 200; V,. = 0.25 -
7.0% and flyash = 10 -70%) are given in Tables 4.6 to 4.8. 'The above results are critically
31inIyszd and also compared with the flow characteristics of 1:3 cement / cementitious
11lorrar and composites. Based on the above, salient inferences are summarizcd as bclow:
(i) Flow behaviour of cement mortar 1 :4 are similar to that of cement mortar 1 :3.
(ii)
I-Iowevcr, Win ratio of refcrnce mortar (1 :4, flyash = Vr= 0%) gently increases
with increase in the required flow value with the maximum at a flow value of
170, Al the masi~n~im llou v:~luc of 120, the W/R ratio ~.ccliiircd is 0.74 which
sllows an incrcasc oi' aboul 14'% over 1 :3 mortar compositcs. Ilowcvcr, thc
above increase is not substantial.
Moreover, the increase in W/B ratio at the maxinlum flyash content (i.e.70%)
is in the range of 36-45% with an average of about 40% which is nearly equal
to that of cement mortar 1 :3, under identical conditions. In terms of absolute
valuc, ~~~asirn~lln Wit3 ixtios ~11.c gc~~cri~llp li)ilncl (o 0.20 I~igIlc~. Llli111 ~ I I C Will
ratio at the corresponding flow values of reference mortar (i.e. 1 :4; fibre = Vi. =
1% J.
(iii)
(iv)
Flow bchaviour ol'cemcnl mortar composites (1 :4) are also similar to that of
cement mortar composites 1 :3. However, percentage increase in the maximum
W/I3 ratio at ~naxi~nur~i librc conlent is lbiincl to be 28-30'!4, \vitli an avcragc of'
about 29% over the WIB ratio at corresponding flow values of reference
mortar, thus showing as increase of about 70% in the average WE3 ratio over
1 :3 cement mortar composites, under the above conditions.
The phenomenon of cumulative demand for water due to the incorporation of
fibres and flyasli into cement mortar 1:3, is also exhibited in flyash-cernent
mortar con~posites 1:4. The actual increase in the W/B ratio at maxinlum fibre
content and flyash content and at corresponding flow values is found to lie
within a narrow range of 0.49-0.5 1, with and average increase of 0.50, over the
WIB ratio at identical conditions of reference mortar (1 :4, flyash = Vf = 0%).
However, the above increase in W/B ratio under the above conditions ranges

from 69 - 88%, with an average value of about 76%. (over the WIB ratio at
corresponding flow values of reference mortar and for the range of flow values
considered).The above average value is about 61% higher than the average
(percentage) increase 111 LV/B ratlo, over 1.3 flyash - cement mortar con~posites.
(j) Cement / Cementitious Mortar Composites - 1 :5
[:low chasactcristics ol'ccmcr~titious rnortar and compositcs (1 :5; r = 200; Vf.= 0.25 - 2.0%
and flyash content = 10 -70%) are given in Tables 4.9 to 4.1 1. Based on the analysis of the
ahovc rcs~ilts anti coiiip:uing Lliem wit11 thc bchavioili. of' 1:3 i 1 :4 inor[ar composites,
fi)llowing inikrences arc summarized:
(i) Flow behaviour of 1 :5 mortar composites are similar to that of 1:4 and 1:3
mortar composites.
(ii) However, the nlaximunl WIB ratio of the reference mortar (1 :5; flyash = Vf =
0%) fi,r u flow valuc of 120 is 0.82, which is an increase 01' 0.12 (i.c. about
i O1Y") over 1 :4 SC~~I~CIICI: ~iiortar and 0.17 (i.c. aboilt 26%) over 1 :3 rclkrc~~cc
mortar, under identical conditions. In other words, higher W/B ratios are
required for leaner mixes to achieve identical flow values for reference mortar,
which is along expected lines and it is due to the influence of actual binder
content of the mix on the flow values of mortar.
(iii)
I:low bchavio~ir of ccmcnl mortar compositcs (1 :S) arc also similar to Ihat of
cement mortar composites 1:3 and 1:4. However, percentage increase in the
maximum WIB ratio at maxiinum fibre content is found to be 27-29% with an
average of 28%, over the WIB ratio at corresponding flow values of reference
mortar, which is same as the behaviour of 1:4 composites under identical
conditions.
(iv)
The phenomenon of cumulative demand for water due to incorporation of
fibres and flyash into cement - mortar 1:5 is also exhibited in flyash - cement
mortar composites 1 :5. The actual increase in W/B ratio at maximum fibre and
flyash contents and at corresponding flow values lie within a narrow range of
0.59-0.64, with an average increase of 0.62. In terms of percentage increase,
W/B ratio under the above conditions ranges from 79-84%, with an average
value of about 84% (over the WIB ratio at corresponding flow values of
reference mortar and for the range of flow values considered). The above
(percentage) increase is marginally higher (i.e. 10%) than 1 :4 flyash-cement

composites and about 79% higher than 1:3 flyash cement composites; under
identical conditions.
]'rc.nds of the above \,ariation of v~.ater 1 binder ratio 01' flyash - ccrneut mortar. cement
II~o:.~;:I. C ~ I I I J ~ S i~nti ~ ~ Cthc S ccmcntilio~~s lnol.tar composilcs 01'
the range of desired flow values are shown in Figs. 4.3 to 4.1 1
I :3, 1 :4 and 1 :5 miscs l'or
.
I hc sprcad of the fresh composite mortar specimen before and after the required number
of'blows in the table test arc shown in Fig. 4.34 (a) and (b) respectively. It is seen that the
spr~ad of the composite mortar specimen, after the test is uniform, due to the presence of
lil,sc>s a:itl scgscgation ilocsll't taltc place. 'l'his sllows Iho i~scl\iliicss ol'tllc :ii~oic Lcst.
4.2.4 Rheolog of Sisal Fibre Mortar and Composites
(A) Cerfrent Mortar Composites ((nt various aspect ratios)
Cohesion (C) values of sisal fibre cement mortar composites (1 :3,W/C = 0.65 ;1:4,
WiC = 0.67; 1:s. W/C = 0.71) for aspect ratios ranging lion 0 - 300, arc prcscntcd in
'l'nblcs 4.3 (a) to
4.2 (c). 'l'hc variation in cohesion values with respect to fibre constants
for the range of aspect ratios considered are shown in Figs. 4.12(a) to 4.12(c) for 1:3 to
1:5, respectively. Following are the salient inferences drawn from the analysis of the
results in Table 4.2(a) and comparing the cohesion values of the composites with that of
thc ~cfcscncc ~iiix (i.~. witliol~l S~S;II
i 1) 1 :3 Mortar
(i)
(ii)
(iii)
(iv)
fiI71.c ant1 I1y::sh):
Cohesion values of the composites (1:3) are generally higher than that of the
reference mortar (i.e. without sisal fibres and flyash). Cohesion of the composite
increases with increase in sisal fibre content, and the above behaviour is found to
be indepcndcnt of the various ranges of aspect ratios considered.
Cohesion values of the conlposite also increases with increase in the aspect ratio,
for a particular fibre content. The above behaviour is also found to be independent
of the various fibre contents considered.
Rheological behaviour of the mortar composite i.e. 'cohesion' which is a measure
of 'stability' of the mortar composite in 'wet state' bears an inverse relationship
with that of 'flow value' which is a measure of 'mobilily' of the mortar composite
in wet state, over the range of fibre contents and aspect ratios considered.
Higher cohesion values are obtained when the fibre content in the composite is
higher, for all aspect ratios considered. The highest cohesion value is obtained

(i.e.140 kPa) for the aspecl ratio 200-300, and when the fibre content = 2.0% in
the composite, which is about 4.4 times higher than the cohesion \dues of
reference mortar (I :3, without fibres and flyash). Moreover, the actual increase in
ilic maximu111 cohcsion valucs of tlic co~iipositc over the rcfcrcncc mortar gcntly
increases upto the aspect ratlo 65 -135. beyond which tlicrc is slight I'all 1.e. in ihc
cohesion values of the composite.
(1) 1 :3 and 1 :5 Mortar Composites
('oinixirillg (Ilc rhcologic:~I bchztvious of 1 :3 and
1 :5 ccmcni iiio~.l;l~. coiiip~si~cs
/'!'ahlcs 2(b) lo 2(c)], \,villi ~lial 01' i : composilcs, Ihllo~ving inl'c~.cnccs ha\.c bccn i!ra\vn:
(i)
(ii)
(iii)
Variation in the cohesion, values of the composites (it. 1 :4 and 1:5), with
respect to the fibre contents and aspect ratios, and the relationship with flow
values of 1:4 and 1 :5 conlposites, all follow the same trend as that of 1 :3
co~nlx)silcs.
I-Iighcst coliesion valucs obtained for 1 :4 and 1 :5 composiles, i.c., 138 kPa and
134 kPa respectively, are found to be marginally less than the highest cohesion
value obtained for 1 :3 composites, under identical values of the parameters (i.e.
fibre content and aspect ratio).
I-Iowcver, in terms of thc act~~al i~icrcasc in the maxili~uni valuc of cohesion
attained, over the respective reference mortar values, it is about 6 and 8 times
for 1:4 and 1:5 composites, respectively, and about 1.4 to 1.8 times higher,
when con~parcd to the increase in the cohesion value altained by 1 :3 composite.
13) Cohesion Vs Flow Values
The influence of aspect ratios and fibre contents on the 'cohesio~i values' of the mortar
co~nposites are also brought in the l~igs.4.12(a) Lo 4.12(c), as cvidcnt Srom the lncrcasc in
the slope of the regression lines, especially for mortar composites of 1:4 and 1:5 (i.e.
mixes leaner than 1 :3) than 1 :3 mortar composites. It can also be seen that the variation in
the trend between 1 :4 and 1 :5 mortar composites, is insignificant, Trend lines of cohesion
values obtained [Figs. 4.3(a) to 4.3(c)] also exhibit the 'inverse relationship' between the
'[low valucs' [l:igs. 4.12(a) 10 4.12(c)l and cohcsion vulucs Ibr thc various morlar
composites and for the ranges of parameters considered.

I 4, i

(iiij
pnrticiiI1lr ic\'el. tlicrcby contributirig !o the increase in llow value of' the mix.
Hence there will be reduction in the cohesion value/(s) of the mix.
For a chosen flow valiie, coiicsion value of the mortar is maximuni when the
fly ash content is rnaxiniuni (i.e, @ 70%) and it is true over the range of flow
\,:\IIIcs
~ollsidr~.~(I.
i I lowcvci., the inasimum cohosion valiics ol'ilic 11101.1111. CICC~CLISCS, ;IS illc dcsirc~l
(v)
(vi)
flow value increases, which is quite anticipated. The reduction in cohesio~i.e.
at maximum fly ash content of 70% is about 2.5 times. The above reduction in
cohesion values has occurred over 2.5 times increase in the range of flow
vnlucs, considcrcd.Thc nhovc reduction is due to :ihotlt I. I
tinlcs increase in tlic
I i I I I Illc 3 'I'l~is sllo\vs illai fly as11 is scnsiiivc lo
water content in the mix, beyond a certain point, and hence it contributes to the
increase in flow value of the mix.
lncrcase in the maximum cohesion value due to incorporation of fly ash Sor a
desired flow value, decreases gently, as the flow value increases and it is found
to hc within 35-22 iil'a, li,r (llc Ixngc ol'ilow vali~cs considcroii.
It car1 be coniidelltly stated that incorporation of ilyash in mortar is advantages,
and has contributed to the improvement in the cohesion value of flyash cement
mortar, over cemcnt mortar mix (I:),
within the rangc of flow values
considered. In terms of percentage increase in cohesion, for maximum fly ash
content in the mortar mix, it rangcsfrom 38.5%) to 168%). or in other words, the
percentage increase in cohesion is three-fold within the range of flow values
considered. Moreover, higher the desired flow value, higher is the percentage
increase in the coliesion value of the niortar tnix, over the 'reference mortar'.
(21 Cement Mortar Com~osites- 1 :3
Incorporation of sisal librcs in (he ccnicnt mortar mix (1:3, fly as11 conicnl - 0'!4/;,;
Vf = 0.25% -2.0%) has contributed to the increase in cohesion values, over the range of
flow values considered. (Table 4.1;). The influence of incorporation of sisal fibres in the
cemcnl niortar, 011 the cohesion value of the composite is sutnmarized, as given below:
(i)
Due to incorporation of sisal fibres, cohesion value of the cement mortar
co~npositc tins incrcnscd whcn comparccl io the cohcsion vuluc ol' 1.cl'crcnc;c
mortar (fly ash content = Vr = 0%). 'l'he above phenomenon is independent of
the fibre contents in the mix and the range of flow values considered.

ili)
(iii)
(iv)
(v)
!Is tlic fibre contcnt in tlic compositc increases, cohesion valuc also increases
for a particular flow value. l'lic sarlle trend is exhibited for all {low values
considered.
Cohesion value of the composite is maximum when the fibre content is
maximum for a desired flow value. The above phenomenon is found to be
independent of the range of flow values considered.
Tlic actu:tl incrcasc in thc niasiniilni cohesion value of the composite at
maximum fibre content (2.0 %) ranges from 37 to 24 kPa, over the reference
mortar and corresponding to the lowest and the highest values of flow values
considered
In terms of percentage increase, the cohesion values at the maximum fibre
colitcnt in Lhc colnposilc, rongcs I'l.orn 40 - 17_0'%,, over (hc rilllgc 01'
llow valucs
of' considered. Moreover, higher the desired flow value, higher is the
percentage increase in the cohesion value of the composite, over the 'reference
niortar'. The above phenomenon is similar to that of flyash-cement mortar,
under identical conditions. The above increase in cohesion values of the
co~ii~x)sil~, is COI~~J>;II~:II~IC 10 [lie J~CI.CCIIIII~C ~I~CI.C;ISC in ~Iic masini~~~ii colicsio~i
value of flyash-cement mortar mix (Table 4.12) and that there is only a very
slight improvement in the maximum cohesion value attained by the composite.
13) Flyash -Cement Mortar Composites-1 :3
The cumulative effect on the cohesion value of the composite, [due to the incorporation of
sisal fibres and fly ash] for various dcsircd flow values, is sun7niarized in Table 4.14.
Following are the inferences drawn based on the critical analysis of the above results:
(i)
(ii)
Cohesion values of flyash-cement mortar composites are higher lhan (a) that of
the reference mortar (1 :3; fly ash content = Vf = 0%); (b) that of fly ash-mortar
(1 :3; fibre content = 0%) (Table 4.1 2) and (c) that of cernent-mortar composites
(1 :3; fly nsl~=O'%; ctc.) ('l'ablc 4.13).
Cohesion value of the composite are maximum, when the fibre content in the
composite is also maximum; for the range of fly ash contents considered. The
above phenomenon is found to be independent of the flow values considered.
The above trend is identical to the effect of incorporation of flyasli and sisal
librcs scparatcly in rhc celiicnt moslar mix ( 1 :3).

(iii)
(i\')
(v)
The maximuim cohesion value that is attained by the composite is 146 kPa (at
fly ;tsh contcnr=70°A1; VI.= 2%), wl~icli ~CC~C;ISCS wih incrcasc in flow valuc, to
a cohesion value of 66 kPa. over the range of flow values considered. In tenns
of actual increase in the cohesion it ranges from 55 to 47 kPa value [with
reference to the cement mortar (fly ash=O% and fibre content = O%)]
corresponding to the lowest and the highest flow values considered.
Considering the 1iii1xini~l111 i~icrcilsc ill tile colicsion valuc of the composite,
\'~1t11 Llli~t 01' L I ~ c 1llil~illlt1111 ~IICI.C~ISC in LIIC
and
cohesion value o1'1hc mix ( I :3), dilc
to the incorporation of fly ash and sisal fibres, independently (Table 4.12 and
4.13): it is found that, there is 'no cumulative effect' in the maximum cohesion
values attained by the composite. This is attributed to the 'sensitivity' of fly ash'
to incrcnsc in thc water content anti hcncc, pnrr of tlic ~I~CI'C~ISC in the cohcsion
val~~c is lost to compensate !'or thc above bchavio~~s and hence 'cum~~lalivc
effect' in the maximum cohesion value attained by the composite is not
realized unlike the 'water demand' of the composite under identical conditions.
In terms of percentage increase, the cohesion values at the nlaxinlum flyash
and fibre contents, ranges from 60% to 247%, over the reference cement
mortar (1 :3, Ily as!]= Vi. = 0'3)) and over the range of' flow values considered.
Moreover, the trend in the percentage increase of the cohesion values of the
composite, is similar to that flyash-cement mortar and cement mortar
composites: undcr identical condi~ions. 111 otllcr words, tl~crc is a fo~~r-fold
increase in the maximum cohesion value of the composite, in spite of 2.5 times
incrcasc in thc llow valucs. which is a trcmcndous impsovcmcnt in the
cohesion value of the composite.
(4) Cementitious Mortar Composites - 1 :4
Rheological properties i.e. cohesion values of cement mortar, flyash - cement mortar and
flyash - cement mortar composites (1:4; flyash content =lo-70%; Vr = 0.35-2.0%) are
given in 'l'ablcs 4.15 to 4.17, 1.cspcctivcIy. I3~1scd on thc itnalysis ol' ~ hc abovc scs~~l~s anil
on 'comparing them with the rheological behaviour of 1 :3 composites, under identical
conditions, following salient inferences are summarized:
(i)
Rheological behaviour of 1 :4 reference mortar (i.e. cement mortar 1 :4, flyash=
Vr= 0%) with respect to chosen range of flow values arc similar to that of 1 :3
I'C SCITIICC Illortill..

(ii)
(iii)
(i\')
(v)
(vi)
Behaviour of cohesion values of flyash-cement mortar 1 :4 with respect to: (a)
in flow val~~es; (b) incrcasc in ilyasll content in thc above mortar mix and jc)
~iiasi~il~~~il collcsio~l v;~Iiic I'i~i- ;I cllosci~ llow valtlc, arc siliiilar to LII;IL of' tllc
bzhaviour of cohesion of' flyash cement nlorlar 1 :3, under identical conditions.
Moreover, the increase in cohesion values at nlaximum flyash content and over
the range of flow values considered for 1 :4 flyash-cement mortar is coiuparable
to that of 1 :3 flyash-cement mortar, under identical conditions.
I lo\vcvcr, p~cc111~g~in~rc;~s~
col~csion a1 masirnuin Ilyasli conten( ranges
from 38 -182% at corresponding flow values over the reference mortar, which
is marginally higher than that of flyash-cement mortar 1 :3.
Rheological behaviour in terms of col.iesion values of 1:4 cement mortar
co~nposites with respect to: (a) fibre content for a particular flow value and the
tangc ol'flo~~ values considcl-cd; (b) masirnun1 cohesion valilc for tl~c range of
libre contents and flow values considered, arc similar to that of thc bel~aviour
1 :3 cement mortar composites, under identical conditions. Moreover, the act~~al
increase in the cohesion values (19 - 41 kPa) and the percentage increase in
cohesion values (i.e.30-135%) over the reference mortar (1 :4,flyash= Vr = 0%)
are also comparable to that of 1:3 cement mortar composites, under identical
condi~ions.
Rheological behaviour in terms of cohesion values of 1 :4 flyash-cement mortar
composites with respect to: (a) fibre content; (b) flyash content; (c) maximum
cohesion value over the range of flow values considered and (d) 'non-
realization of cumulative effect' are all similar to that of the behaviour 1:3
flyash-cement mortar compositcs, ~~ndcr identical conditions. Moreover, the
actual increase in the cohesion values (i.e.41-54 kPa) and the percentage
increase in the above value (i.e.65-270%) over the reference mortar (1 :4; flyash
= Vf = 0%) are also comparable to that of 1:3 flyash-cement mortar
composites under identical conditions.
15) Celiic~ltitious Mortar Coni~ositcs - 1 :5
Rheological properties i.e. cohesion values of flyash cement mortar, cement-mortar
Composites and flyash-cement mortar composites (1:4; flyash content= 10 -70%; Vf =
0.25%-2.0%) are given in Tables 4.18 to 4.20, respectively. Based on the analysis of the

,~bove resi~lts and on colnpari~ig thcm with the rheological behaviour of 1 :3 and 1 :4
composites, under identical conditions, following salient inferences are sumniarized:
( i ) Rlicologic~~l ix~li;~\~ioo~
01' 1 :5 ~~ksc~icc ~iiostar :111tl mor.(as coml,ositcs
(iij
(ccrncnl f ilynsli-ccii~cn[) arc similal. to [hat 01' 1 :3 and I :4 r.cSc~.cncc mortar
and Inortar composites, undcr identical conditions.
However, the only differelice observed is with respect to the actilal and
percentage changes in the cohesion values attained by the 1:5 liiortar 1
composites, undcr typical conditions. which olonc arc Iiighliglited below.
(a) ,"\clil~~l i11ci.case (i.c. 18-33 l

(i)
(ii)
(iii)
Compressive strength of cement mortar composites increases, with increase in
fibre content upto O.j%, beyond which the strength decreases. The above
phenomenori is found to bc independent of age of the con~posite (i.e. from 28
to 120 days).
Maxirntl~ii strcngtli is nttailicd when [he fibre content in the conipositc is 0.5'%,
!by all the ages considered and that the abovc strength is 25 - 61% higher than
the plain cement mortar strength (at the corresponding ages).
Morcovcr, the maximurn strength attained increases will1 incrcasc in agc and
that there is about 44%, 104% and 112% increase in the maximum strength, at
thc ages of 56 days, 90 days and 17-0 days, rcspcctively, over the 28 days
strength of the cement mortar con~posite at 0.5% ( i.e.26 MPa).
(iv) The maximum long - term strength - gain ratio of the composite is about 2.1
i.e. ratio of the compressive strength @ 120 days (i.e. long-term) to that @ 28
days (i.e, at 'normal age'),
Co~npressive strength Vs fibre content of cement mortar composites also exhibit the above
[rends I:ig. 4.22 (a) to I'ig.4.22 (d) and that the conipressivc strength is Sound to be
maximum @ fibre content =0.5%, for all ages considered.
(B) Fly ash - Cement Mortar Composites
Compressive strength of fly ash-ccment mortar and flynsli - cemcnt mortar composites
(13; at Vs= 0.25% - 2.0% and flyash contents = 10%-70%), @ 28, 56, 90 and 120 days oS
normal curing, are given in Tables 4,21(a) to 4.21(d). Compressive strength Vs fibre
contents for the above parameters are also shown in Figs. 4.22 (a) to 4.22 (d). A closer
analysis of the above results yields the following inferences:
(1) Strength a, 28 davs (Normal - age)
(i)
(ii)
(iii)
Co~npressive strength of fly ash - cement mortar increases with increase in
flyash content, upto 20% in the mix, and thereafter the strength decreases till
the fly ash content is 70% (i.e. the maximum level) in the mix.
Similar trend is examined by flyash - cement mortar composites also, over the
range of fibre contents considered.
Co~~ipressive strength is nii~li~lli~~ii ~vhcn tlic fly ash contcnt is maximum (i.c.
70%) in fly ash-cement mortar and in fly ash cement - mortar composites, and
that the actual strength attained is about 28 -55% of the corresponding cement

mortar 1 cement mortar composite strengths (i.e, flyash content = O%),
range of fibre contents considered.
over the
(iv) Compressive strength of flyash - cement mortar is maximum (i.e.29.5 MPa)
when the fly ash content is 20% in the mortar. The strength of flyash - cement
mortar composite is niasimum (i.e.39.5 bll'a) when the flyash content = 20%
and Vl = 0.5'%, in the composite.
(v) There is at least 40% increase in the maximum strength attained by fly ash -
cement mortar and flyash-cement mortar composites, over the corresponding
strength of cement mortar and cement mortar composites, within the range of
fly ash contents 1 fibre contents considered. This is a substantial increase in the
strength: in spite of' replacement of 01'C by Ilp ash, which can be definitely
attributed to the 'cementitious property' of the fly ash used in this study.
(vi)
(vii)
The niaxinium conlpressive attained by the flyash - cement mortar composite
(i.e.39.5 MPa) is about 103% higher than that of the plain mortar strength (i.e
flyash = Vf = 0%) which shows that there is a substantial gain in the strength of
thc above coniposite.
However, comparable 1 higher strength to 1 than that of plain cement mortar
can be achieved, only if, the fly ash content is limited to a rnaximum of 20% in
the fly ash- cement mortar /composite and the fibre content to 1.5% in the
mortar composite.
(2)'Strenrytli at Later - Agcs (i.e.56 - 130 davs)
Based on the analysis of long-term compressive strength data of the composites, [Tables
4.21 (b) - 4.21 (d)] and comparing them with the strength of plain mortar and cement
mortar composites, following inferences are drawn:
(i)
Later- age strength alid normal - agc strcngtli of thc niortar ; compositcs arc
I'ou~~d to bc similar in bchaviour, with rcspcct to the strength - gain, over ~lic
range of fibre contents and fly ash contents considered.
(ii) However, there is continuous increase in strength beyond 28 days and upto 120
(lii)
days which can be attributed to the 'pozzolanic' activity of the flyash used in
this study for the mortar 1 composites.
'I'he rate of' strength development ceniontilious mortar con~posilc is Sound to be
higher upto 90 days and it is also independent of fly ash contents in the mortar.

iil,)
Comparable / higher strength with / than that of plain cement mortar can be
achieved, even at later - ages, as long as the flyash content is limited to a
maximum of 20% and fibre content to 1.5% in the flyasli mortar i composite,
respectively.
(L ) ('oiisi~i~l.ilig the ~iiasinii~m str-ciigtl~ ol'tlic ccmcnlitioi~s composites at Iatcr agcs
(i.e. at fly ash content = 20%; Vr = 0.5%), the increase in the strength over the
corresponding plain cement mortar strength (i.e. flyash = 0% ; Vf= 0%) ranges
Iloi11 l03'%, to 60'2).
( 1 )
Strength - gain of the composite is higher in normal age, than in later ages,
(vii)
(viii)
OVci' p\;li!I ~llOS(i\l' ~11.~11glIl. ']'his ])I.OVCS the 'cc~nc~llilioiis' i11liI 'pozxo;llnic'
p~.opci.[ics of'lly~~sl~ ~ISCC! ill (Ilcir stuiiy. Mol~covct., ~l)cl,c is it conibinccl positi\/c
effect of the fibre and the fly ash used on the strength of the mortar !
composite.
The maximum strength attained by the cementitious composite (i.e. 76 MPa at
120 days. flyasli contcnt = 20%: VI. = 0.5%) is about 73% highcr than the plain
ccnlc111 11io1'Lul. slrc1lgLI1, \vllicll is vct,y s~~!>sla~llial.
The maximum long - term strength-gain ratio of the cementitious conlposite is
about 1.9, which is also very high and comparable to that of the cement
composite (under identical conditions). This proves that there is positive
influence of tlic chosen pozzolana i.e. flyash, on the strength developnient not
only illiring tlic carly - agc, hill illso, dui.ing Iatcl - i~gcs.
Trends in the variation of conipressive strength of flyash- cement mortar composites: with
respect to the range in fibre contents and flyash contents considered at norri~al-age and at
later-ages, as summarized above are also seen in the Figs. 4.22(a) to 4.22(d). It is also seen
very clearly from the above Figs, that the co~npressive strength of the cementitious
composites is maximum @ Vr= 0.54 and flyash contcnt = 20'>L, fbr all ngcs considc~.cii.
4-2.6 Flexural Strength of Mortar Composites
(A) Cement Mortar Composites
Flexural strength of cement mortar composites (1 :3; Vf = 0.25% - 2.0%) at various ages
28 -120 days, arc presented in 'l'ablcs 4.22 (a) to 4.22 (cl) and lhc variation in thc strcngtli
with the above parameters are also shown in Figs.4.23 (a) to 4.23 (d). Bascd on the

a!inI>sis 01'
the above sesulls and comparing the compressive and flexural strength
behaviour of the composites, following inferences are drawn and presented:
(i)
(ii)
(iii)
(iv)
Flexural strength behaviour of cement mortar composites is similar to that of
the compressive strength, within the range of fibre contents and ages
considcrcti.
Flexural strength of cement mortar composites is also maximum when the fibre
content is 0.5%, for all the ages considered and that the maximum strength is
about 3453% higher than the corresponding plain niortar strength, over the
range of ages considered.
The maxiinurn flexural strength attained (i.e. @ Vs =0.5%) increases with
incrcasc in age and that rhcrc is about lG1l/o, 9I'K) and 120'!/;) incrcasc in thc
strength, at the ages of 56 days, 90 days and 120 days, respectively, over the
n~aximuln strength of the composite (i.e. 4.5 MPa) at 28 days.
The maximum long-term flexural strength ratio of the cement mortar
composite is 2.2, which is nearly the same as that of the compressive strength -
~.nti ol'ccn~cut rnol.i:tl. composites 1111tlcl. idcnticitl condilions.
Flexual strength Vs fibre content of cement mortar composite also exhibit the above trends
[ Figs. 4.23 (a) - (d)] and that the flexural strength is found to be maximuni @ fibre
content = 0.5%, for all the ages considered.
Flexural strength of fly ash-cement mortar and fly ash-cement composites (1 :3) at various
fibre and fly ash contents and at various ages of normal curing are presented in Tables
4.22 (a) to 4.22 (d). From a closer analysis of the above results and comparing them with
the co~npressive strength behaviour of the coniposites, following inferences are drawn:
(1) Strcnnth at Normal - Age (5) 28 days2
(i) Flexural strength behaviour of fly ash - cement mortar and fly ash -
(ii)
cement mortar composites are similar to that the compressive strength,
within the range of flyash and fibre contents considered.
Flexural strength is minimum, when tlie fly ash content is maximum
(i.c. 70'X)) ill thc Ily ash-ccmcrit ~norlas, and in the flyash - ccnlcnt
composites and that the actual strength attained is about 25% - 40% of the

(iii)
(iv)
(v)
(vi)
cor~-csponding cement mortar / ccmcnt nlortar composite strengths (i.c. fly
ash content = 0%): over the range of fibre contents considered. The above
behaviour is also comparable to the conlpressive strength behaviour of fly
ash - ccmcnl mortar / composite.
Flexural strength of the mortar 1 composite is also maximum under
idcnricul conditions as []la[ 01' tl~c coniprcssivc strcng~h of 111ot-tar /
composite. The maximum flexural strength of' llyasli - cement mortar and
flyash - cement niortar composite are: 3.7 MPa and 6.7 MPa, respectively.
There is an increase of 20 - 60% in the flexural strength over tlie
corresponding strength of cement mortari composites, within the range of
Ily;~sll :' li1x.c co~ilcl~ls coilsiiic~.ctl. 'I'hc ahovc incl.c;~sc in s~scrigtli is
st~bs~antial. which again could bc altributcd to t l 'ccincntitioi~s ~
property'
of the fly ash used.
Maxi~llum flexural strength of flyash - cement niortar composite is (i.e.
6.42 MPa, when the fly ash content = 20% and the Vf = 0.5%), is 113%
higher Lila11 the plaili ccrncnt mortar st~.cngtIi, ~vliich is a siibsta~itial gain in
Ilcxurai slrcngtli. 'l'hc above sircngtli - gain is compnr.ablc to thc gain in
compressive strength of the composite, under identical conditions. In fact
there is a slight improvement in strength-gain, under flexure.
Similar to the behaviour of compressive strength, comparable flexural
strength than that of plain cement niortar can be achieved, only if the fly
ash contcnt is iiini~cd to a maximum of 20'%, in the Ilyash mortar I
composite and the fibre content to 1.5% in the mortar 1 composite.
(2) Strength at Later - Ages (i.e. 65) 56-120 days)
(i) Later-age and normal age strength behavoiur are similar, over the range of
paramctcrs considered.
(~i) 'I'ozzolanic action' at later ages is also evident fro111 strengths attained by
the mortar/composites, beyond 56 days and upto 120 days.
(iii) Considering the maximum flexural strength attained (@ Vf = 0.5% ; fly
ash = 20%), during the later ages, the increase in flexural strength ranges
from 113 to 70%, over the corresponding plain cement mortar strength.
The above bchaviour is colnparable to that ol' tlie compressive strength,
under identical conditions. In fact, there is a slight improvement in the

(iv)
(v)
ahovo s!i.cngtIi - gain. Morcovcr, tlic 'cciiicillitious' and '~oz..zolnnic'
propcrLics 01'
tlic fly ;1s11 ;~nd[lie co~nbinc~! pc)sitivc cf'1'Cct 0S tllc jibre and
the fly ash have also been established in influencing the flexural strength
of the composite.
The ~naxirnurn flexural strength of 12.6 MI'a attained at 120 days (VI. =
0.50%; fly ash content = 20%), is about 70% higher than the plain niortar
strength at the corresponding age. l'hc abovc strength - gain almost eqi~als
the con~pressive strength - gain, under identical conditions.
Moreover, the niaximum long - term (flexural) strength - ratio is 1.97 (i.e.
ratio of' 111aximi1m ilcxur.al slrcnglli (3 120 days lo that of tllc slscngth @
28 days) ~vhicl~ is also equal to the behavoiur of the coniposite in
conil~~.~~ssioi~,
I rends in the variation of flexural strength , the fibre content and flyash content at which
the above strength is maximun~, are all similar to that of the compressive strength of the
mortar composites, as seen from Figs. 4.23(a) to 4.23(d) and on comparing them with the
trends seen of Figs.4.22(a) to 4.22(d).
4.2.7 Split -'l'cnsilc Str-cngtli of ~Mort;il- Conlposites
(A) Cement Mortar Composites
Split - tensile strength of sisal fibre cement mortar co~nposites (1:3) at various fibre flyash
contents and at various ages (38-120 days) are presented in Tables 4.23 (a) to 4.23 (d).
Split tensilc strength Vs fibre contcnls li)r rllc nbovc parnmclcrs arc also shown in
Figs.4.24 (a) to 4.24 (d). From the analysis of the above results and on comparing the
above strength behaviour with that of compressive and flexural strengths, following salient
inferences are drawn:
(i)
(ii)
Split - tensile strength behaviour of cement mortar composites is similar to that
ol' thc cornpressive and flexural strengths, wilhln the range of Iibic contents
and ages considered.
Split-tensile strengtli of cement mortar composites is also maximun~ when the
fibre content is 0.5%, for all the ages coilsidered and that the lnaxilnuln
strength is generally about 20 - 30% higher than the corresponding plain mortar
strength, ovcr the rnngc ofagcs consiciercd.

tiii!
(iv)
'he mnsimiim split - tensilc strength increases, with age and that the increase
is ~iboii~ 2SO,iO';,b
(i.e.5.O MPa), at 28 days.
and 5496, over the maximum strength of the composite
The maximum long - term split - tensile strength - ratio of cement niortar
composite is 1.6, which is slightly less than that of cement mortar composites
in conlpression and flexure, under identical conditions.
( llatio of' thc niasimum splii-tcnsilc s~rcngtli lo thc maxinium compressive
strength of the conlposite under identical conditions, and for various ages, is in
the range of 13 to 19%. with an average value of 15.8%. The above (average)
ratio indicates good performance of the composite, under direct tension.
'i'lic aho\c rscntls ;ii.c csliibi~cd in I:igs. 4.24 (;I) - 4.24 (11) and [liar ~lic s~~.ong~li is
masin~unn @ fibre content = 0.5'/0, for all the ages considered.
(B) Fly ash - Cement Mortar Composites
Split-tensile strength of fly ash - cement mortar and sisal fibre fly ash-cement composites
(1:3) ;I( V;II.~OLIS lit31.c and ily ash contents, and at varioi~s agcs of normal curing arc
presented in 'Tables 4.23 (a) to 4.23 (d). Comparing the strength behaviour of the above
composites with that of the compressive and flexural strength behaviour, following
inferences are drawn:
(i)
(ii)
(iii)
Split-tensile behaviour of flyash-cement mortar and fly ash - cement mortar
composites are similar to that of the behaviour under compression and flexure,
within the range of parameters considered.
Split - tensile strength is minimum, when the flyash content is ~naxirnum i.e.
70% in ~hc Ilyash - ccmcnt ~iiort~u and Ilynsh - ccmcnl colnpositc ~uid thni lhc
actual strength attained is about 55 - 64% of the cement mortar i cement mortar
composite strength (i.e.flyash - content = 0 %), over the range of fibre contents
considered. The above behaviour is also comparable to that of the behaviour of
the other two types of strength (i.e. compressive and flexural) of the composite.
Split-(cllsilc of' tllc lilo~.[i\~. 1 coinposilc is iilso rnnxi~ii~~rn 1111ilcr iclcnlicirl
conditions, as that of the compressive and flexural strengths of nort tar /

coniposite. 'l'lle maximum split - tensile strength of flyash - cement mortar and
flyash - cement mortar composite are : 4.7 MPa and 5.9 MPa, respectively.
i ) There is an increase of about 17 - 40 % in the strength over the corresponding
(v)
(vi)
cement mortar ! composites within the range of parameters considered. The
incl.casc is slllwl;~nlial ;111tl cornlx~sahlc to thc corrcspoii~ bchaviour of Ihc
other two types of strength, considered.
Maximum split - tensile strength of flyash - cement mortar conlposite
(it. 5.9 MPa, @j fly ash content = 20 %, Vf = 0.5 %), is 42% higher than the
plain cement mortar strength. The above percentage increase in the maximum
strength is about one-third of the increase in the n~nxini~~m coniprcssive and
llcx~~ral strengths, cvaii~ated under identical conditions.
Comparable I higher split - tensile strength with / than that of plain cement
mortar can be achieved, only if, the fly ash content is generally limited to a
maximum of 20% in the flyash mortar 1 composite and the fibre content to
1.5% in the mortar 1 composite. This behaviour is also idenrical with the
behaviour ol'othcr two strengths considered.
(2) Strength at Later-Ages (i.e. 56 -120 davs)
(i)
Later age and normal - age split -tensile strength behaviour are similar over the
range of parameters considered. Influence of 'pozzolanic action' is evident
from tile slrcngtli altaiiied by the n~ortn~~/composiks bcyond 56 days and uplo
120 days.
(ii) Considering the maximum strength of the composites (at Vr = 0.5%;
(iii)
(iv)
fly ash = 20%) during the later - ages there is an increase of about 30 - 48%,
over the corresponding plain cement mortar strength, which is substantial.
Mnsinium splil-lcnsilc strcngtl~ 01'9.2 MI'a atk~incd 01 20 days, (Ilyasll content
= 20%; V1. = 0.50%), is about 48% higher than the plain mortar strength a1 the
corresponding age. The above long-term strength-gain is about 70% of the
strength-gain of the other two types of strength, under identical conditions.
The maximum long-term split-tensile strength - ratio (i.e, ratio of maximum
split tensile strength (@ 120 days to that at 28 days) is 1.6, \vhicli is less than
16%, when compared to rlie otlier types of strength. However, it can be
confidently stated that there exists a similar behavouir among the three types of
strengths of the mortar/ composites.

(v)
Ratio of maximum split-tensile strength to the compressive strength under
identical conditions and for various ages, is in the range of about 12 to
15'!/;1.with :In :lVCl':lgC v:lille 01' 14.0(%1. 'l'hc i~bovc (avcragc) ratio is colnpar.ablc
to that of the beiiaviour of cement mortar composite and indicates a good
performance of cementitious composite, under direct tension.
Trends in the variation of split-tensile strength Vs fibre contents are similar, including the
;lllll
at which the abovc strength is maximum, to that of the compressive strength
/~CSLII.;I~ S L I ' C I I ~ L I I
to 4.24 (d).
Of'~~lll~ll[iliOll~ 1110rLi11. C ~ I I I ~ ~ S ~ L C S , >IS CV~CICIIL ii.oln {hc I:igs. 4.24 (11)
4.2.8 Impact Strength of' Slabs: Mortar and Composite
(A) Cemcnt Morfar atid Cemenf-Mortar Conzposite Slabs
Impact strength characteristics of cement mortar slabs and cement-mortar composite slabs
(@ 28 days) are presented in 'able 4.24 (a). It can be seen from the above results, that the
energy absorbed after initiation of first crack and upto failure is only nominal (i.e. from
9.25 to 10.0 .Tonlcs only). I-Icncc, tlic inlicrcnt ductility of tlic ccnicnt mortar slab, wliich is
rcllcclcii in 'I,,' valuc is vcsy less a~ict is ccjual to I .Oil. 'l'llc 'above villilc is ralicn as tllc
reference', to obtain the relative performance of various mortar slabs 1 composite slabs.
As the fibre content in the cement mortar slab increases, energy required to cause
'initiation of crack' and 'final failure' goes on gently increasing and that energy absorbed
is ~naximum @, 2%) fibre content, i.c. i 8.9 and 35.5 Joulcs, respcclivcly. 'l'his shows the
ductility imposed by the fibres on the composite. In terms of energy absorbed there is an
improvement of 2.04 and 3.56 times than the corresponding energy required for the
'reference mortar slab'.
Residrlal impact strength ratio (I!,) wl~ich is a measure of ductility inherent in the material,
ill~i~oscs gently wit11 incrc;lsc in 1ibr.c contcnt li)r tllc ccmcnl rnorlitr composilcs :uld is in
range of 1.27 to 1.88 for the above composite, wilhin the range of fibre contents
considered. However, I,, of cement mortar composites, relative to that of the cement
mortar slab (i.e. reference, with Vf= O%), denoted by 'I,, , ranges from 1.1 8 10 1.74. This

~i:es the range of ductility improvement that could be achieved due to incorporation of
fibres (i.e.0.25% to 2.0% in this study), in cement mortar slabs.
(2) I,ater - Age Behaviour (i.e. 56 - 120 davs)
!~l,l~oct strcngtll cliaracicristics ol'ccmcn~-mortar s!abs at latcr-ages (i.c. 56-120 days) :we
gi\.c~i in 'l'ables 4.24 (b) to 4.24 (d). Based on critical anal\.sis ofthe above results and on
comparing them with the early-age behaviour, following inferences are presented:
(i)
(ii)
(iii)
Later-age behaviour of cement mortar slabs are similar to that of early-age
bchaviour, Lvith rcspcct to the ericrgy absorbed. I lowevcr, increasc in energy
;~hsorbccis s\~bst:~nti:~l upio 00 clays nncl illat [lie ~nasimum val~ic is icacllcil 61)
120 days, within the range of ages considered.
Maximum energy absorbed for initiation of crack and at failure @ 130 days
are,l3.8 and 18.0 Joules respectively, @ 120 days, which is about 1.5 and 1.8
times over the corresponding values of the reference mortar slab.
In Lcnlis ol'!,,, i11cr.c is only a gcntlc variation over [tic va~.ioirs agcs consiilcrctl
and lies will1 in a narrow rangc of 1.20 to 1.30. I-Iowevcr 'I,,
of thc composites
is in the range of 1.1 1 to 1.20, (i.e.about 20%) indicating only a marginal
improvement in the ductility of the composite slabs, over the early-age
behavoiur, within the range of later-ages considered.
(B) Fly ash - Cerncnt Mortar and Flyash - Cerncnt Mortar Conlposite Slabs
(1) Normal - Age Behaviour (@- 28 davs)
Impact strength characteristics of flyash-cement mortar and fly-ash cement mortar
composite slabs at 28 days, are given in Table 4.24 (a). Based on the analysis of the above
results and comparing them with the behaviour of cen~ent mortar 1 composite slabs,
following inferences are drawn and presented:
(i)
Energy absorbed for initiation of crack and at failure of fly ash-cement mortar
slabs increases, with increase in the fly ash content in the mortar upto 20%,
beyond which, there is a drastic reduction, i.e.til1 the flyash content in the
morlar is 70'X). '1 his is duc to highcr rcplaccmcnt lcvcls of01'C by fly ask (i.c.
40-70%) in the nlortar slab, which might have led to incomplete strength -
development within the normal age considered.

(ii)
The above trend is also exhibited in I,, , but the changes are found to be gentle,
when compared to the energy absorbed by the slab.
(iii) Maximum energy absorbed by the fly ash-mortar slab (i.e.at fly ash content =
20°41 in tlic mortar) is 16.7 and 20.0 .louIcs, at 'first crack' and at failure,
~~i*s~~ccl~\~cl~ , wl~icl~ is I ,X I i111cl 2.0 1i111cs lligl~c~. tl1;111 ~licor~.cspo~~di~lg cticrgy
absorbed by the 'reference mortar'. This increase may be attributed to the
'ccmetitious property' exhibited by the fly ash used in this study, during the
carly-age.
(iv) Actual 'I,,' values, of fly ash-cement mortar slab. lies in the range of 1.14 to
(v)
(vi)
(vii)
I .O. 1.01. llic I.angc 01' Ily ~rsll contents coi~sicicl~cil. I Io\vcvc~.. will1 ~.cfi'r.cncc to
thc reference mortar, 'I,,' lics in the range of 1 . 1 I to 0.93. the maximum value
corresponding to fly ash content = 20%, and the minimum value corresponding
to fly ash contcnt = 70%~. Iletice, it can bc stated safcly that thc fly ash-cemcnt
mortar slab with fly ash content = 20%, has given a better performance in tenns
of d~~ctility ovcr thc ccnicnt mortar slab and fly ash-ccnicnt mortar slabs, wit11
higlicr Ilyash coll~cllts in Lhc slab,(i.c.
20'X/;,).al normal ngc.
Normal - age behaviour of flyash - cement mortar composite slabs are similar
to that of cement mortar composite slabs, with respect to the energy absorbed
for a particular fly ash content and for the range of fly ash contents considered.
I lowcvcr, the encrgy absorbcd by the composilc slab is maximum, when thc fly
ash content in thc liiortal. colnposi~c is 20')/;1, bcyonil wliicli, drastic rcduclion in
the impact strength behaviour is observed, which is similar to the behaviour of
fly ash- cement mortar slab under identical conditions.
Maximum and minimum energy absorbed (for initiation of crack and at failure)
by the mortar coniposite slab, at 20% fly ash content are : 22.2 and 59.5 joules
((il), 2'%, 1ib1.c colilcnl) a~~tl 17.7 :~iitl 20.5 ,jot~lcs(at 0.2Si!4, !ihl.c colllcnt),
respectively. The above values are 1.91 and 2.65 times (for 0.25'% fibre
content) and 2.4 and 5.95 times (for 2.0 % fibre content), respectively, over the
energy absorbed by the reference mortar slab, which
shows the tremendo~~s
improvement in the ductility and the role of sisal fibres in enhancing the
ductility of thc composite.
(viii) In terms of 'I,,', the relative improvement in ductility is 1.39 and 2.48 with
respect to the reference mortar slab and corresponding to Vf = 0.25% and Vf =
2.0 % and at a flyash content of 20%. Comparing the above values with 'I,,'of

the fly ash -cement mortar slab, at fly ash content = 20% and VI. = 0% i.e.
1.11, the relative improvement in the ductility of fly ash-cement mortar
composites (3 fly ash content = 20%; ,@ 0.25/0 and 2% fibre content), in
terms of I,, are: 1.25 and 2.23, which again is a tremendous increase. This
sliows [lint there is cumulative positive influence of the inherent cementitious
~I.o~cI'[~ of' tllc fly asti liscii alicl tile cl~icfili[y 01' [lit librcs ill crllianci~ig [Ilc
performance of the fly ash-cement nlortar composite slabs over the range of
fibre contents: even at the normal - age.
(2) Later-Age Behaviour (@, 56- 120 days)
Iiill';~ct sl~.crlg~li cli;~~.;~c[ci.i.~tics
01' i1),;1sh -ccmcllr Ii1oi.tar slahs anti Ily ash-ccrncnt mortar
composite slabs at taler-agcs (i.c. 56-130 days) arc givcn in 'l'ablcs 4.24 (b) lo 4.24 (d).
Conlparing the above results with that of normal - age behaviour and with that of cement
mortar 1 composite slabs, following inferences are drawn:
(i) Behaviour of fly ash-mortar slabs at later-ages are similar to that at normal -
(ii)
age, based on the cricsgy ahsor-bctl by tlic slabs aiid tlic range of fly ash
contents considercci.
However, there is continuous improvement in the energy absorbed by the
mortar slabs beyond 56 days and upto 120 days, which is due to the
'pozzolanic action' of the flyash used, at later-ages, irrespective of the flyash
content in the timrtar. Rut, ill spite of the above 'pozzolanic action', the
strength of flyash mortar slabs couldn't matcli the strength of' cement-mortar
slab (in terms of energy absorbed), especially, when the fly ash content in the
mortar slab is greater than 20%. Therefore, energy absorbed by the fly ash-
cement mortar slabs are also lnaximulll when the fly ash content in the mortar
(iii)
is 20%, cvcn at latcr -ages.
I:ncrgy :~bso~~bcil by tllc Ilynsli-ccnicnl morlar slz~b is mz\simum $6 120 days (at
a fly ash content of 20%). The above energy corresponding to initiation of
crack and at failure, are 20.3 and 32.5 Joules respectively, which is 2.19 and
3.25 times the energy absorbed by the 'reference mortar slab'. The above
values are also higher than at nonnal - age i.e.1.2 and 1.6 times, respectively,
~~ntfes identical contlitions, wliicli sliows that Llic 'pozzolanic action' or fly ash
used has played a prcclomi~iant role in enhancing ~lic rll~ctility of ~lic mortar
slab, during later - ages.

( ) i,'I>. ;tsll - ccnicnt Inor.Lur cciniposilc sl~~bs csliil>it siriiili~i l-cllavio~l~., i1t lalcr-
ages. with respect to cncrgy absorbed over the range of' fibre contents and fly
ash contents, considered.
,
Energy absorbed by the flyash - cenient mortar composite slabs is maximum
when thz fly ash content in the composite is 20% and for the range of fibre
contcilts considcrcti. 'l'lic nbovc bcl~a\,iour is sii~~ilar to that 01'
fly ash - ce~iicllt
mortar co~iipositz slabs at tile normal - age ancl that of' cenicnt mortar
composite slabs at all ages. Energy absorbed by the composite slab is
ma sir nun^ I@
120 clays ( Ilyasli content = 2O'j/o), col.rcsponding to 0.25%, and
2.0% fibre contents in the composite, are: 40 and 82 Joules. respectively. 'I'he
rlbovc values are 4.32 lilnes and 8.2 tirnes the cncrgy absorbcd by the refercnce
ri1o1-liu slab and 2.27 ~iriics nilti 3.00 times than that of' tlic ily :!sli-ccrncnt
mortar composite slabs at nonnal-age and under identical conditions. The
above behaviour clearly proves the 'positive influence' of the 'conibined action
of fibres' and the 'pozzolanic action' of fly ash in enhancing the ductility of the
composite slabs at later-agcs.
(\'I) In 1c1.1iis of' 'I,.,', Lllcrc is only a gcntlc inlpr~)v~nic~i~, over lllc silngc 01'
(vii)
paranleters considered. Corresponding to the maximu~n energy absorbed (i.e.
fly ash content = 20%, at 120 days), it ranges from 1.95 to 3.05 over the range
of fibre contents considered. In terms of relative improvement in ductility
('I,,'), the range is 1.81 to 2.82. Con~paring the above performance of the
coilipositc \vitIi tllilt 01'
Ily ash-ccmciit [nortar composite at normal- age and i hi^
of cement illortar composites, at all ages, tliere is a tremendous increase in the
ductility of the composite at later-ages also, once again proving the combined
positive influence of fly ash and fibres, over the range of parameters
considered.
Tn casc, eo~iiparablc / liighcr impact streligtli of the composite is desired to 1
than that of the reference mortar slab. at all agcs, then, the flyash content bc
restricted to a maximum of 20% and fibre content to 1.5% in the cementitous
composite.
Impact strength Vs fibre contents for the various ranges of parameters and ages considered
are shown in Figs. 4.25(a) to 4.25(d). Trends with respect to incrcase in fibre and flyasli
contents, as summarized above are also seen in the above Figs. Moreover, trends in the

ositcs (i.c. sIaliil;~~.tl sl~cci~iic~is), li)llowing i~li'crcnccs rl1.c ilrawn:
(i)
(ii)
(iii)
(iv)
Behaviour of composite mortar slabs are generally similar to that of flexural
strength of standard specimens of mortar and composites, within the range of
parameters and ages considered.
Flexural strength of reference Inortar slabs (CM 1 :3, fibre content = fly ashl
content= O'K,) is Soi~nd Lo bc 3.03 MI'a, (at 28 days), which is comparnblc to the
strength of reference inortar specimens under flexure. However, the strengths
are always lower, at all later-ages. Moreover, the later-age strength of slabs
(a120 days) are about 30% lower than the strength of flexural specimens.
Flexural strength of fly ash-cement mortar slabs, have similar strength
bcliaviour with that ol' Ilexural spccimciis, for all fly ash colitelits and for all
ages considered.
Flexural strength of cement mortar composite slabs and flyash-cement mortar
composite slabs are maximum at the fibre content of 0.5% and at all ages,
which is also similar to the flexural behaviour of composite specimens
(evalualcd by thc slantiard proccdurc). I-lowevcs, Ihc maximum strcngtli
obtained by the composite slabs are always less than the maxin~u~ii strength

attained hy the spccilncns (in flcx~nre) at all agcs considered. The above
plicnoiiici~o~l nlab hc il~ic lo iiic '~.csiii~ial slrcss' pi.cscni in the slal, spccimcns
due to the impact rest, conducted earlier.
I:Iesural strength of mortar conipositc slabs Vs fibre contents, for the various parameters
cnrisidered are shown in Figs. 4.26 (a) to 4.26 (d). Composite inortar slabs exhibit similar
ircniis as [hat of various lnortar conlpositcs, for thc above strength, including the
~i~lainrncnt 01' ~iiaxinlum strength. The primary objective of' tlic abovc test is to obtain the
.reference data' for determining the 'flexural toughness factor' (I-[) of the composite slabs,
iifti.1. exposing them in NaOH and, hence, to eval~iate the 'durability of the composite'.
fractured speciniens of composites after the flexural test using the impacted speciniens,
(Sol. [hc rangc ol' 17aramcters considcrcci), arc givcn in I:ig. 4.37. It is sccn that all
spccicnicns, exhibit a typical 'Ilcsural ii~il~irc' anti tlial librc I'racturc is obscs\lcd.
4.2.10 DurabiliQ of Sisal Fibre Composite .Mortar Slabs
LA) Evaluation of Durability Based on 'I,,: -
Iii~~i:~ct sl~.cllglh ol'ccnicli( i' Ily :IS\>-ccnicnl iiio~.la~. sluhs, ccincnl / I1y;rsh - cciilcnt nlorlar-
co~npositc slabs, alicr exposing Llici~l in NaOl l niccli~i~ii, arc given in 'l'ablc 4.26, li)r
various fibre contents. Comparison of 'I,,'
values before and after exposing the composite
slabs in NaOH medium are given in Table 4.27. From a critical evaluation of the above
experimental data, following observations are obtained:
(i) I:., values of cenicnt nort tar ancl Ily ash-cctiicnc inortar slabs dccrcases afcr
exposure in NaOI-I. In other words, the ability to take impact loads al'ter exposing
the slabs in the alkaline medium has reduced, due to interaction between the
matrix and the medium under consideration, leading to strength-loss of the matrix
after exposure, which is reflected in the I,, values of the slabs.
(ii) Whcn the fly ash content in the fly ash-cement mortar slab is 20%. 'I,-,' values
after exposure is maximum, considcsil~g thc range of fly ash contents c.onsidered.
However, it is less than the corresponding value (i.e. 1.60) before exposure in the
alkaline medium. This shows that the 'negative influence of the alkaline medium'
on the fly ash-cement matrix is minimum, thereby, the durability of the matrix is
relatively enhanced at the above fly ash content.

(iii) Morcovcr, 'I,,' values for all fly ash co~itents upto 60% in the fly ash-ccmc~it
niortnr arc liiglicr than the cexcnt mortar. not only before but also after exposure,
iii llic alkaiinc inctliur~i. 'l'iicsc i~g~~in sliow ~II;II iiicot.poratio11 01:
Ily ;isli cnlianccs
the durability of the matrix, against the negative influence of'allialine niedi~im like
NaOH on the matrix. Therefore, fly ash incorporated in higher - volumes i.e. even
ilpto 60% in the fly ash-cement mortar slabs can match the durability of the
cement mortar slab, when exposed in KaOH medium.
[i\ i 'I;,' L;I~LICS 01' CCI~CI~~ 11iOi.litt. cotiil)osilc s I ~ I I ~ s ~I~CI.C;ISCS will ~I~C~C;~SC in lih1.c
content, al'tcr exposurc in the ~dliulirii: iilcdi~~m, wlicii coliiparcd to ~hc I,,
valuc
before exposure and it is found to be independent of the fibre content. 'Irs' values
of the above composite slabs afrer exposure have the same trend as that of slabs
before exposure in the alkaline medium and that it is maximum when the fibre
contcnt is li~asinlurn i.c. 7_.0'%, iii tlic CCII~CI~~
mortar. co~i~positc slabs.
(v) 'Irs' values ol'lly asli-cement mortar composite slabs alicr exposure cxliibit similar
trend as that of 'I,,'
values of cement mortar composite slabs, over the range of
fibre contents and fly ash contents considered and that it is maximum when the
fibre content is maximum (i.e. 2.0%) in fly ash-cement mortar composite slabs,
for a particular fly ash content.
(vi) I-lowever, 'I,.,' values of' llyasli-cemcnt ~i~ortar compositc slabs aftcr cxpos~irc in
the alkaline medium is maximum, when the fly ash content is 20% , and it is true
for the range of fibre contents considered. The above trend is also similar to the
trend before exposure of the above coniposites in the ail

intion on in 'I,,'
values after exposure in the alkaline medium have also been coniputed
:]nd esprcssed as a percentage of relative change in values ( Eqn. 4.3 ) with respective to
1 1 : ~ I,, \;~\i~cs oI7i;riiicd 1~c.li)l.cspost~~,c in iiic ;llli;llinc ~iictli~lm. Sol. :\I1
~o~~~iiiercil.
the ~ypcs oi'slnbs
[R2-R1 I
Ileviation in 'I,,' = X 100 ...
I
I)c\ i;llio~: ill 'I,,'
\,;:lllcs 11111s ol7l;iincti arc gi~cliri 'T;ihlc 4.28. /\ closer lnoli at [he ;tbovc
~.csiilis p~.csciits an intc~.csti~ig sccllario, i.c. (i)
'I'l~c deviation in I,,
values of' all plain
mortar slabs, are all negative, indicating nearly failure of matrix, due to exposure in the
alkaline medium; (ii) the deviation in 'I,,'
positive as 'I,,'
values of ail composite mortar slabs are all
values of co~nposite slabs after exposure are higher than the correspondillg
~~alues before exposure for tlie reason Is stated earlier; (iii) From the above trend, 'I,,'
L ~ ~ I I L I ~ i11.c S all riii~ii~~i~~~ii (irrcspccLi~~c 01. llic type 01' IIIOI.I;I~ / cor~ij~ositc), wl1c1i tlic lly i~sli
contcnt in the mortar is 20%. 'I'he above result shows that the ~ilatrix and fibres are least
affected when the flyash content in the composite is 20%.
Variation of 'I,,'
Vs librc contents of inortar 1 compositc slabs, (bcf'orc and after exposure
in NaOH medium) are shown in Figs. 4.27 (a) - (b). The above stated trends are clearly
see11 in tllc ;:hove I:igs.
Fractured specimens after evaluating the durability of the composite, by the impact test,
are shown in Fig. 4.38. It is found that the failure patterns are also found to be similar to
the patterns observed, before the specimens are subjected to the durability tcst, and
evaluated by the impact test
iB) Evaluation of Durability Based in Flexural Toughness index (I1.)
Flexural toughness of cement lflyash-cement mortar slabs, cement mortarifly ash-cement
mortar composite slabs, before and after exposure in YaOH medium are presented in
Tables 4.29 and 4.30 respectively, for various fibre contents. Cornparis011 of 1.r values
bclbrc ancl alicr csposing [llc colnposi[c slahs ill tile alkali~~c li~cclit~~~l i11.c l ~ ; . c ~ in ~ ~ ~ (
Table 4.3 1. Deviation in IT values after exposure in the alkaline medium have also been
computed and expressed as a relative change in values
values obtained before exposure in the alkaline medium, similar to 'I,,'
, with respect to the IT
values and

,,, ~L,~ci!~ed
.., . in 'i'albli. 4.32. I:~.orn a closer look 01' tilc above. fblio~ving observations arc
;123de:
(i) I valiles of various mortars ! composites exhibit the same trend as that of 'I,,'
values, with respect to the range of parameters considered.
(ii) I valucs arc all 17iini171~11ii (irrespective of the type of mortar / composite),
~viien tllc llyiisil c~~iiteiit in the mortar is 20%. ']'he above fiict shows that the
matrix and fibres are least affected when the flyash content in the conlposite is
20%.
I'ariation of 'Ir' Vs fibre contents of mortar 1 composite slabs, (before and after exposure
in N:tOl 1 mciiiuln) arc shown in Fig. 4.28.
It can therefore be stared thal the 1, valiies as defined as used here. can be confidently used
to evaluate the durability of natural fibre composites.
4.2.11 Sisal Fibre Corrugated Roofing Sheet
'The above characteristics of sisal fibre corrugated roofing sheets in CM 1 :3 and in fly ash-
cement, mortar (1:3, fly ash content 10 - 30%) are given in Table 4.33. It is seen from the
above results that the sisal fibre corrugated roofing sheets (of mortar i composite) couldn't
match the strength of a comnlercial type of corrugated sheet, popularly available in the
Indian market. Incorporation ol' fly ash upto 30% in tlic fly as11 - cement mortar (I :3), has
yielded comparable load carrying - capacity (i.e. flexural and splitting loads) with that of
cement mortar roofing sheets. Incorporation of sisal fibres into the cement mortar matrix
has gently increased the load carrying - capacity of the above loads upto 1.0 YO of fibre
content, beyond which, the load carrying - capacity have decreased and found to be
~ninimum whcn thc fibrc content is maximum i.c.2.0%, in the cement mortar conipositc.
Similar trends in the above strengths have been observed for the fly ash-cement mortar
roofing sheet also, for the range of flyash contents, considered.
Incorporatioll of sisal fibres into ce~nellt mortar and flyash - ce~ncnl 111ortar has improved
the load carrying - capacity of the above in the composite corrugated sheets, upto a fibre
conlclil 01' 1%)
cciiicnl 11ioi.tai. composite sliccts. 'l'lic maximum Ilcx~~ml load atlaincd
by the cement / flyash - cement mortar composite corrugated sheets are generally found
to be about 25% higher than the cement I flyash- cement mortar roofing sheets (reference,

~villlol~i sisal li\>~.cs). :I[
I .OiXr fihrc co~ilc~it, arid withill tllc ri111gc 01' llyi~sli contents 1 librc
contents, considered. However, the maxi~niim flexural load (i.e, about 180 kg) carried by
the coniposite roofing sheets are found to about 85% of the corresponding strength of the
'commercial type roofing sheet' tested under identical conditions.
Tl~c bcliaviour of tlic conipositc roofing slicets undcr tlic 'splitting load' sliects is found 10
hc .sig~liIic~i~ltly Jil'l21.cni. w1ic.11 co~npascil Io llic Ilcx~~ral lonil cassyi~lg - capacily,
especially, for fly ash content at 20% and fibre content = 1%,
at which the splitting load
carried by the above conlposite is maximum and that there is 66% increase in the splitting
load over fly ash mortar sheet (with fly ash content=20%) and 100% increase over that of
the cement mortar sheet. The above improvement in the splitting load of the composite
SIICC~S
is I~CIIICII~O~IS. \vl~icIi is ; I ~ I I ~ ~ I ~ lo ~ I (IIC ~ C ~ ~)osi(i\,c
I
~I~~~LICIICC
oI'I1y ;~sil i111d III>I.cs in
[lie co~iipositc. I-Iowevcr, the iiiaxi~iium splitting load of the above con~positc is about 87'%
of the corresponding load of the commercial roofing sheets considered and equals the
performance of the above con~posite under flexure load. Moreover, the increase in
splitting loads of the composite is found to be generally double the increase in flexural
loads and it is foulid to be indcpendent oftlie type of mortar used in the composite. When
tlic fly as11 conlent in the co~i~positc is 30%, the maximum splitting load of tlie composite,
even though has reduced to nearly 45% of the strength of cement mortar sheet and 28% of
that of fly ash mortar sheet with fly ash content = 30% , it is still comparable to the
strength of cement mortar roofing sheet. Hence, it can be safely considered that at fly ash
co~itent = 20% and fibre content = 1.0%, tl~c flexural and splitting loads of the composite,
yicld nearly comparable rcsults with that of tlic commercial roofing slicct considercd.
However, further improvement may be possible by adopting better casting procedures,
which incidentally may lead to incorporation of higher sisal fibre content in the composite,
and hence improvement in overall performance of the fibre sheets.
Fig. 4.29 and 4.30 show the variation in the above stre~~gtlis for the various mortar /
composite, in tlic Ibrm ol'a hislogram whcrcin, thc abovc trcnils arc csliibitccl.
(B) Impact Strength
The results of the above test on sisal fibre corrugated sheets in CM 1:3 are given in
Table 4.34. It is seen that, the sisal fibre corrugated roofing sheets perform very poorly
when compared to thc 'commercial typc', in tcrms (hc actual cncrgy absorbcd undcr thc
impact load. But, the 'ductility' nleasured in terms of 'I,,',
of the com~nercial typc of'

corrugated sheet is lower than almost all mix combinations considered for the impact
stuii ics.
Inco~poration of sisal fibres in the cenlent mortar had generally contributed to comparable
"marginal
in~proi,ernent in the impact strength and 'post-cracking behavior', i.e. 'd~~ctility'
111casurcd in terms of 'I,,',
lo that of plain cement mortar shects, upto 2'% of jibrc contenl
in the composite sheet. Inlpact strength characteristics of fly ash cement mortar composite
co~.rug;~ccd shccts arc ilol signi[icaiilly impi.ovcd tii~c lo ~hc incorporalioii oS Ily ~isli,
especially, the 'ductility' of the composite, as evident from the I,, values.
However, in
terms of actual energy absorbed there is substantial improvement up to at least 1% fibre
content and with 10-30% fly ash content, in the composite. From the point of actual
energy absorbed (i.e. at initiation of crack and at failure) and ductility in terms of I,,,
cos~x~gatctl hl~ccts with 2011/;r Ily ;~sli anil i'%, IiI71.c coiitcnr in tlic composilc, arc hc((cr/
compiisablc lo tllut ol'ccnlclii nlortar- cors~lgatccl sl>ccts {i.c. control).
Variation in I,, with respect to fibre contents, shown in the form of histograms (Fig. 4.3 I),
for the various mortar / con~posites, exhibit the trends as slated above.
(C) Wder Absorptiori
W:I~~I. ;~I~sol.ptio~~ cl~:~~~~~clc~~islic~s
of' \;:)sio~~s 11loI~lili. conlposi~cs i11.c givc~i in 'l':~l~lc 4.35,
Even though the percentage of water absorption was found to be more than two times for
cement and fly ash cement mortar based corrugated sheets, when compared to the
comn~ercial type sheets, cement niortar and fly ash-cement mortar co~iiposite corrugated
sheets have shown improved performance with respect to water absorption characteristics.
The impsovemcnt i.c. reduction in thc watcr absorOcd, incrcascs with fibre contcnl ~ipto
1% in the cement 1 fly ash-cement mortar composites and over the range of fly ash
contents considered. In fact the best performance is obtained when sisal fibre content is
1% and fly as11 content is 20%) in the composite used f'or the cosrugatcd shccts, for which
the water absorption is the lowest (i.e. about 36% of the commercial roofing sheet). Fly
ash ccmcnt niorlas conipositc shccts linvc shown bctlcs pcrformancc (i.c. in Lcrms of Icsscs
percentage of water absorption) over the entire range of Ily ash contents considered, whcn
compared to the commercial type and cement mortar composite sheet.
The above
phenoinenoil is generally due to the impermeability imparted by the flyash to the niatrix.
The variation in water absorption with respect to fibre contents for the various mortars /
conilositcs, shown in Pig. 4.12, cshihit ~lic nhovc sti~tcd lrcnds.

Fractured specimens of corrugated sheet after the impact test and splitti~ig test on
ci,rl.~~g;~lions (Vl.= I .O'Kj ; llyi~sh conicnl - O -- 30'!4,) i11.c sliown in I:igs. 4.39 to 4.40. I1 is
sceli tha~ the spccinlcns exhibit a typical f'ai1~11.e paiicrn i.c. along the corn~gation, ~lndcr
the two types of loading.
(D) Water Tightness
Results of the watcr tiglitness tcst on tile various types of corrugated shccts (i.c. celi~cnt/
\Iv ahl~-ccilic~it iliol.lal. co~npositch) ir1.c givc~l in 'l'ablc 4.30 i111tl ill I"ig.4.33. 11 is sccn
froin the above that the sheets of cement mortar composites exhibit comparable 'water
tightness' characteristic with that of the commercial type, upto 0.75% fibre content in the
composite , beyond which, tlie performance is comparable with the 'commercial type',
based 011 the water tightness exhibited by the cement mortar composite.
Ilou'cver, the water tightness oi' Ily ash - cemznt composites arc generally beitcr than thc
cement mortar composite sheets for all fibre contents and fly asli contents and that the best
results are obtained when the fly ash content in the fly ash-cement mortar composites is
20% and fibre content is 1%. The above improvement in the characteristic can again be
attributed to the i~npernieability that is imparted to the composite, by fly asli.
Results and discussion based on the comprehensive experimental investigations,
encompassing thc characteristics of sisal fibrcs; ~vorl

7rhc best possiblc combina~ion of Ilyasli and librc - coiitcni for sisal fibre roofing slicct has
been identified so as to obtain conlparable performance with that of a popular and a
commc~.ci~\i lypc looling si~ccl. Salicnt conclusions bascd on ~lic prcscnl strrdy arc
in chapter 5.

Aspcct
74
Table 4.2 (a): Workability and Rheological Properties of Sisal Fibre Cement Mortar Composites (at various aspect ratios)
(1:3 mix, W/ C = 0.65, r = 0-300)
SI.
No.
1
2
.3
4
5
6
Note: (1) (A)-indicatesflow value f%j; (8)-indicates cohesion (Pa)
[ii) Flow valzre=lIZ.O% und Cohesion = 32 kPa for reference mortar ( 1 -3, ~virhozrtjhrer andj7y as/7)
Table 4.2 (b): Workability and Rheological Properties of Sisal Fibre Cement Mortar Corr~posites (at various aspect ratioc)
(1:4 mix, Wl C = 0.67, r = 0-300)
SI. Fibre Aspect Ratio
No. con tent 0-35 I 35-65 65-135
(yo) A B I A I B A , B
1 0.25 127 1 25 i 1261 30 1128
--
Fibre
content
(yo)
0.25
0.50
-
0.75
1 .00
1.50
2.00
-- .- .- ~
0-35
A
- 125.7
118.9
.- - -..
-.-
~- -- 91.3
B
3 5
44
2 0.50 L_~L__L 32 _-
35-65
A i B
124 1 42
102.6 1 56
- -. - -. -. .- . -
-1-1 '2 -_- ' -
40 106 I 42
3 0 75 1032 I '38 ---- 1 96 I 46 90 -
4
1 .OO 876 68 76 1 I 83 ~~ 7
- --- - -
5 1.50 83 7 96 -- ---- 74 - 8
6 - 2.00 --. - 66.8
Ratio
65-135
A 1 R
122 1 52
95.6 59
p~
-~ 60.6 ~-.
-- i 76
-. 53 1 74.8 -- 64 .-~
71.4
87 71.1 1 99 58.3 i 106
64.41 100 59.5 1164 55.3 123
62.3 1-72 55.9 1 124 53.3 1 127
- -
Note: (1) (.4)-in(ijcure.~f201(. vc~lzrc I%,. /B/-it7Jicr1ie.s rohr.sion (kPa)
(ii) E-lo~v vulttc- 111. 7% u11d Cohesion = 23 hPa fr referznce tnortrrr- / I:f. ~r,irhozrr-fibre7 unriflj. ush)
-- --
-. -- - - - .- -
135-200 -- -
- -- 200-300 -- .--
A ; H A B
110.5 53 105.5 -- .
--- - -- 6 -- 3
85.9 1 70 78
76
63.0 i 102 57.1 105
4
54.3 117 52
131
44.5 I I26 42.3
36.8 I36 30.5 140
1 134 1

Table 4.2 (c): Workability and Rheological Properties of Sisal Fibre Cement Mortar Composites (at various aspect ratios)
(1:5 mix, WI C = 0.71, r = 0-300)
S1.
No.
1
2
Fibre
content
(%)
0.25
0.50
.O-35
A
128
126.3
B
18
26
'
Aspect Ratio
35-65 65-135
A B A B
126.1 25 113.8 32
86.5 36
105.5 40
A
107.2
101
135-200
B
3 6
47
A
105
98
200-300
B
40
52
Note: (i) (A)-indicatesflow value (99); (B)-indicates cohesion (Pa)
(ii) Flow value=llO.l% and Cohesion = 17 kPa for reference mortar (1.3, withoutfibres andjy ash)

yahlc 4.3: Flow Chsri~cteristics of Flyash-Cement Mortar
(1:3; flyash content=O -70'2,; fibrc content = O'X, )
I S1. Flyash I Waterlbinder ratio for flow values of 1
1 No content
50
60 70 80 90 100 110 1 2 0
I (Oh)
[ 1 0 0.53 0.54 0.57 : 0.59 0.60 0.62 : 0.64 0.65
: 2 ! 10 ----
0.56 0.57 0.59 0.61 0.63 0.64 ; 0.66 j 0.68 I
1 7 20 0.58 0.60 0.62 0.64 , 0.66 1 0.68 0.70 1 0.71 1
Tihblc 4.4: Flow Char~trtcristics of Sislil Fibrr Ccriicnt Mortar Coml~ositcs
(1:3; Ily ~rsll con(cn( = O1%,; I'il)rc conlcnl = 0.25'%, - 2%; 1. = 200)
I F1 Fibre i
Yo content I
I
1 (Oh) 1 50
1 1 0.25 1 0.53
60 70 80 90 100 110 120
0.54 0.57 0.59 0.60 0.62 0.64 0 65
Note: (I) Flow values are expressed us a percentuge

Table 3.5: Flow Cl~aracteristics of Sisal Fibre Flyash-Cement Mortar Composites
(13; n ;ISII cou(cl~t = I o-70'xr; fil,~~
r. = 200)
31.
1 " 1 (w)
cOlliclll = 0.2s-z.o~,;
, 1:ibrc 1 Water:bindcr ratio ['or flow values of I
content
SO 60 70 80 1 90 100 110 120
r--
1
. -
1
+----------
0.25
1
1
(A) Flyash Content = 10%
0.56 0.57 0.58 0.60 0.62 0.64 0.68 0.67
2 0.5 0.56 0.58 0.59 0,61 0.63 0.65 0.67 0.68 i
0.75 0 . 5 7 0.59 0 6 0.62 0.64 0.65 0.66 0.69
-+----
1.00 ! 0.59 0.6 0.63 0.64 0.66 0.68 0.70 0.72
1.50 '0.61 0.63 0.65 0.67 0.69 0.71 0.72 0.74
2.0 0 . 6 4 0.66 0.68 0.70 0.72 0.74 0.76 0.78
(l3)Flyash Content = 20%
&
_ - ._ I .....-.. ...
I
6
-
, 7 1 0.25 0.57 0.59 0.60 0.62 0.64 0.65 0.67 0.69
10
1 00
I 1 1 I 0
I2 k"
11
13
- 0.25
14 --6Tj
15 0.75
17
117 1 1.50
/_-i_l._
!X 2.0
0,76 1
0.64 0.65 0.67 0.6 0.70 0.72 0.73 0.75
005 Oh7 008 0,70 0 0.71 0.75 0.77
0.08 0.00 0.70 0.72 0.7'1 0.75 0.77 40.75)
(C) Flyash Content =40(!h
0.67 0.68 0.70 0.71 0.72 0.74 0.75
0.69 0.70 0.71 0.73 0.74 0.76 0.77 0.78
0.69 0.71 0.72 0.74 0.7s 0.76 0.78 0.80
0.71 0.72 0.74 0.75 0.76 0.78 0.80 0.81
0.73 0.75 0.76 0.77 0.79 0.81 0.82 0.84
0.7.1 0.70 0.77 0.70 0.81 0.82 0.KI 0.85

~
Table 4.6: Flow Characteristics of Flyash-Cement Mortar
(1 :4; flyash content=0-70%); fibre content=O%; r =200)
SI. 1 ii'lyilS~I
No. , content
j (%)
1 1 0
-
50
0.58
- .- - ---- . .
Wittc1.1 I)iritlcr rutio for. flow vlil11cs 01'
- - -- -- -- ----
-- -
60
I --
70 / 80
0.60 0.63 / 0.65
90
0.68
100
070
110
0.72
120
0.74
Tablc4.7: Flow Characteristics of Sis:il Fibrc Ccmcnt Mortnr Composites
(1:4; flyash contcnt=O'%,; fibre content=0.2S1%,-2'X/;,; r=200)
1 SI. 1 Fibre 1 Water/ binder ratio for flow values of 1
1 No. content
50 60 70 80 90 100
--------
(%)
1 0.25 0.58 0.60 0.62 0.64 ' 0.67 0.69 0.71 0.73
2 0.50 0.61 0.65 0.68 0.71 0.74 0.77 0.809 0.83
-- 3 0.75 0.64 c66 0.60 0.72 0.75 ! 0.78 0.8 1 0.84
- .
4 1.0 0.67 0.70 0.730.7(',
---
0.78 0.812 0.84 0.88
5 1.5 0.71 0.74 0.78 0.81 0.85 0.88 0.91 0.93
6 2.0 0.74 0.77 ' 0.80 0.83 0.86 1 0.89 0.92 0.95

Table 3.8: Flow Characteristics of Sisal Fibre Flyask-Cement Mortar Composites
(1:4; flyash content = 10-70%; fibre content = 0.25-2.0%; r=200)
- -
51, l'ibre 1 1Vi1tcrIbi11deratio for !Ion values of
ho content
I
I
'
lJ(iil) 50 60 u 70 80 90 1 0_ 0 _ _ 110 -- 120
-4
1
I (A) Fly:1\11 Content = 10'X1
- -
0 00 0 62 0 65 007 0 60 0 7 1 0 711 0 76 1
0 63 0 65 0 67 0 70 0 72 0 74 0 77 0 70
075 I066 069 071 074 0.76 0.79 081 084
4 100 073 076 078 081 084 086 089 092
5 150 078 080 083 086 088 091 094 096
6
i
20 1082 085 087 090 092 095 097 099
' 12
I
1 I
2.0 10.85 0.89 0.92 0.95 0.98 1.01 105 1.08
I (C) Flyash Content =40%
025__j0.72 074 0.77 0.80 0.82 084 0.87 0.89
I.
17
18
19
; 20
1 21
i 22
I
1.50 1 0.89 0.91 Oi94 0.96 0.98 1.01 1.04 1.06
2.0 10.93 0.95 0.98 100 1.02 1.05 1.07 1.10
1 (D) Flyash Content =60%
0.25
0.5
0.75
0.80 0.83 0.85 0.88 0.90 0.93 0.96 0.98
0.88 0.91 0.93 0.96 0.99 1.01 1.04 1.07
0.91 0.93 0.96 0.99 1.01 1.04 1.06 1.09
1.00 ! 0.93 0.95 0.98 1 .O 1.03 1.05 0 8 1.11 1
(E) Flyash Content = 70%
25 1 0.25 0.87 0.9 0.91 0.93 0.95 0.97 0.99 1.01
26 0.5 0.94 0.96 0.99 1.01 1.04 1.06 1.08 1.11
0.75 0.96 0.98 1.01 1.03 1.06 1.09 1.10 1.13 1

'I'able 4.9: Flow Charilctcristics of' Flyash-Cement Morti~r
(1:5; flyash content=Q-74)(%; fibre content=O'Y~; r=200)
1 -
1 SI. 1 i{ 1~ihh11 Wiltcl bludcr riltio lot. [low v~~Iuc'\ 01
- - - - - - - - - - - - - -
I NO. 1 contcnt --
-
50 60 70180--'-< % I ~ ~ o - I ~ -
(%)
1 0 0 67 069
0 71 0.73 0 75 0.78 0 80 0 82
--~
2 10 0.70 072 074 076 078 080 0.82 084
1 3 0.83 0 85 '0.87
-7
20 0.73 0 75 0770.79 0.81
40 0.79 0 81 0 83 , 0.85 0 87 0.89 091
0 93
60 0 85 0 87 0 8 9 0 I 0 01 0 05 0 07 0 90
76 - 04 1-0 - oo
7);) I 1 o -.
- ' fi - 5~ 1 1 6 I 1 1 ilL1 1 I ( i ~
1 ro(7 1
Table 4.10: Flow Characteristics of Sisal Fibre Cement Mortar Composites
(1:s; flyash content=O'%; fibre content = 0.25'%-2(Y0; r =200)
I Sl. I ITil>~-c, I W:ttcr./ Itir~tlcr I-:tiio libr- llo\v \,l\it~c.s
No.
1
contcnt
('%)
0.25
50 60 1 711 80 90 100 1 10 120
0.65 0.67 / 0.69 0.71 0.73 0.75 0.77 0.79
of
I

Table 4.1 1: Flow Characteristics of Sisal Fibre Flyash-Cement Mortar Composites
(1:s; flyash content = 110-70'%,; fibre content= 0.25- 2.0%; r =200)
S I . Fibre Waterlbinder ratio for flow values of
\o content
I (Yo) r~~ 6 0 70 8 0 9 0 1 0 0 110 120
I
(l3)Flyash Content -- = 20°/0
0.81 0.87 0.85 0.87 0.89 0 . 0.03 (5
0.83 O.S.5 0.88 0 0 0.01 0 0 0.98 1.10
fl
0.97 1.0 1.03 1.06 1.08 1.13 1.16 1.19
0.98 1.0 I05 1.08 1 . 1 5 I 8 2 1
1.03 1.06 1.10 1.13 1.16 1.19 1.23 1.26
1
I
(C) Flyash Content =40%
I 13 0.25 0.92 0.95 0.97 0.99 1.02 0 1.06 1.09 i
~
1 Ill
,-- ..--- - -- 0.5 10.94 0.96 0.99 I . 1.03 1.07 1.09 1.12
.,
1 5 0.75 103 0 i.00 1.12 1.15 I 1.21
16
1 .00 11.05 1.08 1.11 1.14 1.16 1.19 1.21 1.24, I
, 17 1.50 1.09 1.12 1.15 1.18 1.21 1.25 1.28 1.31~
18 2.0
1.11 1.14 1.17 1.20 1.24 1.27 1.30 1 . 3 3 ~
-
19
2 0
2 1
0.25
0.5
0.75
1 01) Flvash Content =60%
I
1.07 1.10 1.12 1.15 1.17 1.20 1.22 1.25
1.10 1.13 1.16 1.18 1.21 1.24 1.26 1.29
1.13 1.16 1.19 1.22 1.25 1.28 1.32 1.35
1
i 1 i (E) Flvash Content = 70% 1

__-_I
Table 4.12: Rheological Properties of Fllyash-Cement Mortar
(12; Ryash ~ontent=0-70~/;,; fibre content=OOh; r =ZOO)
-- -.--------.._.I__--.._I~--___
I ->ir--[-FG;l-s h I Cohesion (Id's) for flow values of I
Table 4.13: Rheological Properties of Flyash-Cement Mortar Composites
(1:3; flyasli content=O%; fibre content=0.2Sn/;,-2%; r =200)
I S1. Fibre 1 Cohesion (Pa) for flow values of
I
50 60
70 80 90 100 110 120 ,
( I
-- - __- .^
1
-_^_.
_
_
I 035 I 110 94 87 76 60 40 35
35
1 2 0.50 ' 114 102 90 78 I 68 54
40 1 28
107 9 5 ; 8 2 ) 7 1 58 -
48 3 3 ,
4 1.0 ; 121 110 98 84 1
--- 75 60 50 37
' 5
114 101 90 ' 78 64 I 55 40
-_~_.___i____p-
6
120 106 95 80 70 58 43
1

'I'iiblc 4.14: liheological I'ropertics of Sisal Fibre Flyash-Cement Morti~r Cornpositcs
(1:3; flyash content = 10-70% fibre content = 0.25-2.0%; r =200)
I
(A) Fljash Contcnt = lO(%
-
I 025 110 94 87 76 60 49
~
35 25 1
05 114 102 90 78 68 54 40 28
0 I16 I07 95 82 7 1 58 48 33 1
1 1 (B)Flyash Content = 20°/0
7 1 0.25 117 107 95 8 0 7 1 59 4 6 33
I
----- 2 20 . I - 134 - 122 I I 08 92 75 6 l I9
(C) l~lqt~sli Content =10'%,
9
13 0 25 120 113 101 88 80 66 52 40
11 05 I122 115 103 90 8 1 67 57 42
15 075 I 128 120 106 93 s 3 7 I 59
45
I6
1 .OO 131 123 108 97 84 74 62 47
j
17 1 50 133 126 I l l 99 87 75 63 5 1
18 2 0 I37 130 115 100 90 77 65 54
136 126 118 103
130 120 108 100
(E) Flyash Content = 70%
I - 25
- -- 025
- 138 1 IR I05 97 86 75 64 53
1
1 26 ----
0 5 Ill 121 I I0 09 87 76 66 55
134 124 113 102 90 80 69 58
28 1 00 138 128 117 105 94 83 7 1
I 29 1 4 2 132 120 109 98 88 75 6o 1
30 1 20 146 138 124 114 I05
90 80 ii 1

P
Table 4.15: Rheological Properties of Flyash-Cement Rqortar
(1:4; flyash content=O-70%; fibre content=0%; r =ZOO)
r----
SI. 1 1;ly:ish I Cohesion (Itl'il) for flow villucs of -7
Table 4.16: Rheological Properties of Sisal Fibre Cement Mortar Composites
(1:J; flyash contcnt=O%,; fibre content=0.25'%,-2'%,; r 3200)
1 SI 1 Fibre '
50 1 60 1 70 80 90 100 1 1 0 120;
I ' (%) I>
1
102 96 I 82 /
---I
0 25
60 56
1 46 33
23
1 2 0.50 108 198 : 83 174 61
50 36 25
3 1 075 -- I I (I 101 1 88
1
75 67 53 .-
44 3 1
-I-
4 I 0 - 116 - I _-. 104 - 1..-_1--
80 60 56 - - 47
---- 34
--
5 120 ; 108 1 97
- 15
96 83 73
59 52 7 X
6
-1 2 0 75 66 54 I 40
-

SI. , Fibre 1 Cohesion (kPa) for flow values of
No, I content
I ( ) 50 1 60 1 70 80 90 100 110 120
, (,4) Flyash Content = 10%
- -- 025 ---
1 104 95 85 72 63 52 4 1 30
0 S 1 o7 0 X R 8 70 0 54 I I 32
075 1 110 100 0 I 80 00 -5 X 17 i 5
I00 1 \ 1 4 I05 94 82 74 60 49
I08 96 84 77 62 52
6 110 102 89 82 67 55 44
I - -
-
(R)Flgash Content = 20%
7
025 1108 99 89 75 66 55 43 3 1
8 0 5 112 103 92 80 70
57 46 34
- 0 75 I I5 105 0 5 84 72 6 1 49 17
10
I 00 - I I0 I10 98 86 7 8 63 52 4 1
I I 150 1 123 113 10 1 88 8 1 65 5 5 43
9
- --
(C) Flyash Content =40%
- 13 0.25 113 107 95 82 75 62 49 37
14 0.5 I 114 109 98 85 77 64 54 40
I
L
I
19 , 0.25
1 20
1 0.5
21 / 0.75
1 22 / 1.00
1 23 1 1 50
I 24 1 2.0
i
25
, 26
27
28
! 29
1 30
0.25
0.5
0.75
1 .OO
1 .SO
2 0
(D) Flyash Content =60%
117 109 98 88 78 66 57 42
120 112 100 90 80 70 59 49
124 114 105 94 84 72 63 53
127 118 110 97 89 77 65 55
131 122 113 10 1 94 8 1 68 59
136 128 I I5 10'3 98 83 73 62
(E) Fly:isll Coutcnt = 70%) -
~
120 I l l 100 92 80 7 1 60 49
123 113 103 93 83 72 62 52
126 116 107 96 85 75 65 55
130 120 109 99 88 78 67 57
133 124 114 102 93 82 70 59 i
137 - 131 119 107 98 84 72 63 J

--
1 p
1
2
I *
.)
4
I 5
I 6
1
'Tahlc 4.18: Rhcological Propcrtics of Flyash-Cctnent Mortar
(1:5; lly;~sll con tcnlt=O-701X,; lil)rc coatcnt=O1X,; r =200)
Cohesion (kPa) for flow \ alues of
1
I
((%) 50 60 7 0 80 90 1 0 0 1 1 0 120 1
0 78 71 68 57 53 3 8 2 9 16
10 100 85 74 63 60 42 34 18
20
- 104 ,--i
88 85 68 5 3 44 38 38
It------
40
107, 06 ---_ 0 I 74 08 ,__-_ 57 -- 45 3 1
-.-
60 106 98 93 77 70 1 60 51 35
70
111 102 1 95 I 75 75 64 55 45
Table: 4.19: Rheological Properties of Sisal Fibre Cement Mortar Composites
(1 :5; fly;isl~ contcnt = (I1%,; libre contcnl = 0.25 - 2.0'%, r = 200)
SI. ,
No.
Fibre
content
1 (%)
I 1 0.25
2 0.50
50 60 70
96
90 77
101 92 80
Cohesion (Id") for flovc values of
80 90 loo i
I
110 120
56 52
43 30 21
69 57 , 47 43 I 23

l'ahlc 4.20: Iihcological Properties of Sisal Fibre Flyash-Cement Mortar Composites
(1:s; flyash content = 10-70%; fibre content = 0.25 - 2.0°h; r = 200)
I (A) Flyash Content = 10% I
I 1 i 0.25 97 89 80 67 59 49 38 28 1
I
-
~ (B)Flyash Content = 20%
7 0.25 I 101 93 83 70 62 52 40 29
8 0.5 105 97 86 75 66 54 43 32
9 0.75 ! 108 99 89 79 67 57 46 35
10 1 1.00 I I i 103 92 80 73 60 40 40
83 76 62 52 42
117 108 100 87 80 66 54 44
I- : - 1 15 106 9 5
L :.-j.-_
2- _-
I 16 1.00 1 IS 109 9 6 8 7 7 6 6 6 5 4 42 I
1 17 1 1.50 I 1 I8 I l l 99 88 8 0 68 5 6 45 1
I (I)) Flynsh Confcr~t =6O'%, . ..
I 10 0 . I10 I02 0 7_ H i -1 i 67, 5 1 10
~
113 105 04 85 75 00 5 5
5 116 107 99 88 79 68 59 50
22
23
24
I 00
1 50
2.0
119
123
128
I l l
114
120
103
106
108
9 1
95
97 84 88
92
73
76 78 6 1
64
68
52
5 jS 8
(E) Flyash Content = 70%
25 1
025
104 94 86 75 67 56 46
(I 05 I00 07 8 8 7X 6 R 5 8 4
1
/
j
j;:
I

Table 4.21(a): Compressive Strength of Sisal Fibre Flyash-Cement Mortar Composites
(13; constant flow value=112'Y0; @ 28 days)
hl.
I Il~utlcr co~ilc~ll ( onil)r.e,\i\c 5Lrellfillr (~1111111') ii( fi111.c ~011te111\ of
1.00% 1.5% 2.00%
I
/
Table 4.21(b): Compressive Strength of Sisal Fibre Flyash-Cement Mortar Composites
(1:3; constant flow valuc=112'%); (ij 56 days)
I SI.
so.
I
Binder content Compressive strength (~lrnrn) at fibre contents of ;
('X;)
*vl
1
I F-4
Table 4.21(c): Compressive Strength of Sisal Fibre Flyash-Cement Mortar Composites
(1:3; constant flow value=112%; @ 90 days)
SI. 1 Binder content ((%) Compressive strength (~lmm') at fibre contents of 1

'l'il[)lc 4.2 1 ((I): ~'o~nprcssivc Str~~~gti~ of Si~i11 Fil)rc l ~ly;~sI~-C'c~~~c~~~
h'lortiir C:o~~~posi(cs
(1:3; constant flow value='il2(%; @ 120 days)
I
--
SI. I Binder content Compressive strength ( ~imm~) at fibrc contents of
I
'I'ablc 4.22 (;I): Flcsurai Strcngtli ofSis:~l IJihl-c Flyi~sll-Ccrncnt Mort:~r Composites
(1:3; constant flow v:~luc=l 12%; (21) 28 dilys)
I
i $1. Binder content ('10) Flexural strength ( ~/mm~) at fibre contents of 1
No.
/ 1
OPC I;* OO!, 0.25'X 0.5%) 0.75'X) 0 0 1.S'Yo 2.OO'X
Table 4.22(b): Flexural Strength of Sisal Fibre Flyash-Cement Mortar Composites
(1:3; const;lnt flow vi~luc=l 12'%,; G) 56 tli~ys)
SI. i
No. ~
1
2
3
j
4
- .-. -
,5
6
Binder contcnt ('%) Iti'lcrur;ll strength (~irnm') i ~ fibrc t contcnts of 1
OPC FA 0% 0.25% 0.5% 0.75% 1.00% 1.5% 2.00°/0 1
! I
100 0 3.4 4.4 5.2 4.6 14.1 13.8 3.3
90
10 4.4 5.3 5.8 5.1 14.6 14.4 3.8
80 20 5.1 6.0 I 6.7 6.5 ' 5.6 / 5.4 4.7
60 - 40
, .. ,...,..
2.7 1 3.9 ! 4.6 ..
4.0 3.9
.....
13.1 2.8
I .- -~ . .- ,
40 60
2,u 1 2.8 , ..-i.15--. 3.0 2.3 i 2.1 I .9
30
70
2.2 1.9 11.7 1.5
1.4 1 2.2 1 2.5

Table 4.22(c): Flexural Strength of Sisal Fibre Flyash-Cement Mortar Composites
(13; constant flow value=112"h; 90 (lays)
SI.
No.
Binder content
(%) - 1
()I)( I !,A 1 0% 0 5 %
Flexural strength (~lmm') at fibre contents of
1 - -- --- -
1 0 I 7 I.OO(%) 1 i.i(X) 1 L.0O1%,
Table 4.22(d): Flexural Strength of Sisal Fibre Flyash-Cement Mortar Composites
(13; constant flow vill~e=112'%); @ 120 days)
1 SI. Binder content ((K) Flexural strength (iY/mm2) at fibre contents of 1
'1';rblc 4.23(;1): Split 'l'cnsilc Strength of SisiiB I'il)rc i;lyasl~-Ccment Mortar Cotnposilcs
(1:3; constant flow value=112(% ;@ 28 days)
SI. 1 Binder content (Oh) Split tensile strength (~imm') at fibre contents of i

~
7';1hIc 4.23(b): Split Tcnsilc Slrcr~gtllr of Sis:tl Fibrc Flyirsh-Ccment Mortz~r
Conipositcs (l:3; constant flow valuc=1 12% ; @ j 56 days)
SI.
No. )
Binder content Split tensile strength (y/mm2) at fibre contents of
('A))
--
OPC F4 0% 0.25% 0.5(% 0.75'%) 1.00'%) l.sO/O 2.00'%)
48 40 39
Table 4.23(c): Split Tensile Strength of Sisal Fibre Flyash-Cement Mortar
Cornpositcs (1:3; constant flow vi~lue=l 12%; 6) 90 days)
I
I SI. Binder content Split tensile strength (31rnrnL) at fibre contents of
No.
I
SI.
No.
Table 4.23(d): Split Tensile Strength of Sisal Fibre Flyash-Cement Mortar
Composites (1:3; constant flow value=112%; @ 120 days)
-- -
Bindcr Content I h q i t tensile strength (~lrnrn) at fibre contents of
((Yo)
I
OI,C j j 0% 1 0.25~~~
j o.s"~) 0.75% 1 1.00% 1 1.50~~
2.00% 1

T'able 4.24 (a): Impact Strength of Sisal Fibre Flyash-Cement Mortar Composite Slabs (1:3; constant flow ~alue=112~!; 28days)
(377 Fibre 1 Impact strength (J) and res~dualrrlpact stre~lgtll
- - - -- -- -- ---
No. content
(Yo)
-
-- 1
- 2
- 3
- 4
- 5
- 6
7
Note (1) A- Impact shen~th - at rnrtratron of crack (rn Jouies)
B- Impact strength at final crack(fu11ure ojspecrn7e)i (117 Joztles)
C- Resrdual impact strenph (denoted as I, J
(11) Fly ash confen1 ~ndrcnred 15 rn the form of a blnori Drtjdrr of OPC and PA
(111) Energy rnrpartedper blow = 0 97 J (for (I hf offail of 20cnlj
(rv) The above are equalh nj~pircnble for data repot red 171 Tables In Tables I ZI(b) ro 124(d)
(I,)
for fly ash coriterlts of
m
P
Table 4.24(b): Impact Strength of Sisal Fibre Flyash-Cement Mortar Composite Slabs (1 :3; constant flow value=112'%; 56clays)
Impact strength (J) and residual impact streiigth (1,)
-- -
for fly ash contents of

'l,il~~lc -I.S(ii): ~ ~ ' I C X I S'~I'CIIR~II
~ I ~ ~ ~ I oI'S~S~II l~'il)~.c ~('I~IIS~I-{'CIII~II~ h'lOl'(ili' {'OIII~)OS~~C SI~II)S
(1:3; coilstant flow value=112'%1; four-poitit loading; (ui~ 28 di~ys)
SI. Binder content Flexural strength (~lrnm') for fibre contents of ~
I
((%)
l
No.
OPC FA 0(!40 0.25% / 0.5'lb T0.75(!40 1.00% l.5'!40 1 2.00iX
'I'i11)lc J.25(b): IJICXII rill St~.~l~gtl~
01' Sisi11 I;ibrc I'lpitsll-Clcn~cnt M0t-ti11- COIII positc Slal)s
(1:3; constant [low valuc=112'%); four-point loading; [ui 56 tlays)
I SI. Binder content Flexural strength (P4/mm2) for fibre contents of ~
so. 0I
1 OpC FA 0.:. 0 . 0 O.j(yv o,li(: I.UO(. I l.i(s 2.1111(:0 ~
I 7-
'1';lhlc 4.25(c): I~lcsor-ril Strcngth of'Sis:~l Fibre F1yilsl1-Ccmcrit Mortiil- Composite Slabs
(1:3; colrstirt~I Ilow virluc=l 12'%,; I'orl1.-l)oin1 Ioatli~~g; irr' 00 clays)
Flexural strength (iV/mmL) for fibre contents of
I
0.5% 1 0.75% 1.00% 1.5'X~ 1 2.00% 1
' - 2 ' 90
- -- 10 4.91 5.34 5.82 5 60 5 52
3 80
4 GO
--
5 40
6 30

'rable 4.25(tl): Ii'lexural Strength of Sisal Fibre Flyash-Cement hlortar Composite Slabs
(12; coasl:lnl Ilo~ vitloc=I 12'%,; Sour.-l,oiat lo:lding; 6) 120 tlilys)
1 Sl. Binder content Flexural strength ( ~ l . / r n m ' v

Table 4.26: Impact Strength of Sisal Fibre Flyash-Cement Mortar Composite Slabs After Exposure in NaOH
(1:3; constantflow value =112%; r=200)
I S1. I Fibre I
Impact strength (J) and residual impact strength (I,,) for fly ash contents of
Note: (i) Energt, for one blow = 0.99J (Height offall = 21cm)
(ii) A- Impact strength at initiation of crack (in Joules)
B - Impact strength atJna1 crack (in Joules)
C- Residual impact strength (Id
(iiij Flv ash content indicated is in a binary binder of OPC onLi r~ ~ s(FA)
h

Table 4.27: Comparison of Residual Impact Strength Ratio of Sisal Fibre Fly ash- Cement Mortar Composite slabs (Before
and After Exposure in NaOH)
(1:3: Constant flow value =112%; r=200)
-- -
I Sl. I Fibre I Residual impact strength ratio (I,,) for flyash contents of 1
No.
1
2
3
4
5
6
7
content
(%I
0
0.25
0.50
0.75
1 .OO
1.50
2.00
R,
1.30
I .33
1.70
1.97
2.20
2.32
2.53
0 O/o 10 O/o I 20% 40% . 60%
70 '10 --
t----
R2 R1 R2 I R1 R2 K1 R2 R 1 R2 .- R1 i Rz
1.22. 1 .50 1 .40 j 1.60 1.58 1.50 1.40-- 1.31
1.25 1.23 : 1 .OO
1.70 1.65 1.81 / 1.95 2.00 1.61 1.71
1.41 1.67 1.35 ; 1.50
2.00 1.81 2.08 1 2.25 2.35 1.75 2.12 1.65 2.00 1.41 1 1.67
2.25 2.00 2.38 / 2.43 2.46 1.81 2.27 1.75 2.1 1 1.62 ! 1.75
.-
2.53 2.30
2.56 1.98 2.33 1.85 2.27 1.75 / 2.00
-
2.68 2.42
2.88 2.21 2.66 2.15 2.53 7.00 / 2.16
2.88 2.60
3.10 2.71 2.82 2.42 2.66 2.15 ) -2.28
: 1- :::
2.88 / 3.05
Note: R, - Residual impact slrength raiio (I,] before immersion in NaOH rnediun~ and qfier 120 clays ofnormal crri-ing (US given
Table #.24(d))
R1 - Residual in~pacl strength ratio (1 J after immersion in NaOH medirtrn and afier 120 days ofnormal curing (us giver
Table -1.26)

'I'ablc 4.28: f'f'f~ct of I;:sl)osur.e in Xi1011 on the I,, ofSis:ll I;i[)l-e I'ly ;bsh-(:crncne Mor.t:tr.
Composite Slabs
(1:3; Constant flow value =112%; r = 200)
7g--~K-l----
- - -
Deviatiorl in I,, for Plyas11 contents of -1
NO.
content
.
18.60
I .O +20.00 t14.78 t1.99 t17.67 t22.70 +14.28
6 1.5 t18.96 t14.04 i5.88 123.92 1 t17.67 I8.00
pp
7 2.0
0
,vll/~':
!/I '/I(' ,l/lOl'O l/l~l'll///ol~ 1l/'l1 c'll!('ll/ll/~'~/ ll'l//l /'~'\/)01'/ i 0 i,$ l 'o/llc'~ f~/'/~,l'~l~/l-/lfl!'~'l/
IIIOI'/~~I' ,\/(l/l,~.YII/)/L,( /1,11' !O /IOI.IIIO! C,!II.~II,L,/~~I' ! 20 1/(/1',\
(iij 7 % ~~bo\'e ~ 1 ~ 1 1 1 i~ic/~c,u/e
1 ~ ~ (11r ~ ~ 1 1 ~ ~ ~ in 1 ~ (IIC 1 0 1 I,, ! (!/://!' ll.\~!-/~~l,\~'l/ t~~i)\~/~i/~ ,\/i~!).s
uJer c7gitlg in n'uOH 123 28 days and as given bi 7hhlr 4.2 7

Table 4.29: Flexural Toughness Index of Sisal Fibre Flyash-Cement Mortar Composite Slabs
(1:3; Constant flow value = 112'/0 ; r = 200 ; @, 120 days)
( SI. I Fibre 1 Toughness index {A21(.-il+Az)) for fly ash contents of
No. content
-- --
0% 10%
(".I
A
BT A B C A
1 n 1322 1 700 1 o 316 11693/
Note: (i 0) -Area of the load-d~splacement diagram upto [he pre-cracking slag- (A,)
(B)- Area of the load-displacement diagram njer the post-cruckit7g ~fnge-(A~j
(C)- Flexural loughness wder -(IT)=
(jl J @)+Ad)

Table 4.30: Flexural Toughness Index of Sisal Fibre Flyash-Cement Mortar Slabs After Exposure in NaOH
(1:3; constant flow value =112%; r =200)
I S1. I Fibre j Toughness index {A2/(AI+A~))
No.
1
2
3
4
5
6
7
for fly ash contents of
.content 1
,
i
(%) j 0% 10% 20%
40% i 60% 70%
-
i A B c A B c A B
C A I B c .---A
B c
0 j 1006.5 368.5 0.268 1103.5 408.1 0.270 1722.3 306.0 0.151 1 902.82 503.4 0.358 1 1284.3 777.1 0.37 823.9 276.1
---
0.25 1 790.8 701.2 0.470 694.4 / 1289.6 0.650 1119.2 869.7 0.380 / 799.0 ' 485.6 0.378 ! j6C18 645.2 0.ili ! 895.0 622.0
0.50 / 198.6 846.7 0.810 1134.4 638.0 0,360 , 1262.6 1824.4 0.591 i 1091.2 1240.3 0532 403.8 1 661.6 0.621 : 445.5 615.3
0.75 i 629.5 1887.5 0.750 339.0 1275.0 0.750 1066.0 2882.0 0.730 1 1303.3 861.6 0.398 / 461.4 / 387.6 0ISI , 453.0 771.4
-.
498.1 0.370 680.0 / 60ib 0.470 1145.2 3867.8 0.728 1 952.5 - 1065.5 0.528 1 2505 1 1836.5 0.880 146.5 667.5
2392.0 0.73 933.9 1984.0 0.680 925.0 3435.0 0.788 299.5 1140.5 0.792 1 262.0 1033.0 0.7% j 334.0 362.0
1084.0 0.770 288.0 912.0 0.760 106.0 1218.0 0.920 1 749.0 1667.2 0,690 171.4 / 1469.6 0.898 j 123.2 57.0
1.00 848.1
1.50 1 885.4
2.00 i 325.0
' __-__-.I--
ATT
c
0.251
--
0.410
0.580 ,
0.6F
0.820 I
0,520
0.770
Note:
(A)-.ires of the load-displacernznt diagram upto he prc-crocking stage- (A,)
(B)- Areu of the load-di~placerncr~ diugranl after the posr-crocking stage-(A j
(C)- Fle~ural toughness inde.~ - I ={AJ(A,+AJ)

Table 4.32: Effcct of NaOl-l on thc Flcxural Torigllncss Indcs of' Sisal Fibrc
Composite Slabs
1 §I. Fibre Deviation in 1, for fly ash contents of 1
No. cootcn t
I 5 1.0 i40 68 -53.59 I t3.11 / i-28 15 t29 41 I 1-32 90
Table 4.33: Flexural and Splitting loads of Sisal Fibre Flyash - Ccrnent Mortar
Corrugated Roofing Sheets
(1:3; specimen size: 250 X 500 X 6mm)
I §I. ( Fibre / Characteristic loads at fly ash contents of 1
!vole: (1) (A)- Flexural Load (kg); (B) Splitting Load by)
(2) Strength of reference sheet (ACC brand), cornrguted sheet, commercial Qpe =
209 kg and 10.77 h' re.ypec(ively, for (A) & (B)

'~,~~blc 4.33: 1oj

Table 4.36: Water Tiglltness of Sisal Fibre Flyash-Cement Corrugated Sheets
(1:3; with and without fibres; after 2411rs)
1 SI. ; Fibre Water tightness for flyash corltents of 1 I
so,
co,,(c,)(
O'%,
(OX) ~
10':/0 20'%/;, I"-' 30'2,
--
-- 0 I L --r-- N
Y
0.25 i L
I I
i 2
īN ~
h'ote: (I),I/oiniion indicated ahol:~ hinv iiie,,ioilowing meani~ly:
/i) IV- " Nojkue wirier" idrips) on ihe ~mn'er siiie qfihe sheet
jii) L- " Signs of dampness is observed", but slich area do not exceed 50% of the iota1
waiei pooled area
iiii) M- " Dum1)nes.r is ohsen~ed" and /he dump area exceeds 50% oj'rhe ~r:iilo.pooled
area
(ivj S- " WQICI ~lropletx are ob.re/ve(i ~iniier the sheel.
(3) ll'tr,c~~. ii,ql7lilclv.c o/'cotiir,icr~,id c.o~.rii,ymrii ,r./~l~c~t ii'os oh.ri,~.~'i~tl lo con/i,r111 /ri
"/V ".
1111~ l ~ l / ~ l ~ ~ ~ l l ~ l '

Flow Values (%)
Fig. 4.3 : Flow Values Vs Water /Binder Ratios of Flyash- Cement Mortar
(1:3; Flyash = 0 - 70%; Vr= 0%) )
~
Flow Values (%)
l
Fig.4.4: Flow Values Vs Water / Binder Ratios of Sisal Fibre Ccmcnt
Mortar Cornposites (1 :3; flyash = O0/i ; Vr = 0.25 - 2.0'%, ; r = 200)
269

Flow Values ('%,)
(a) Flyash Co~ltent IQ'Yo
045 C T - - T i IT---- I
30 40 50 60 70 80 90 100 110 120 130
I'low Valucs ('%,)
~ (b) Fly ash content..20%
I
Fig. 4.5(a) - (b) : Flow Values Vs Waterminder Ratios of Sisal Fibre Flyash - Cement Mortar
Composites (1:3 ; flyash content = lo%, 20% ; Vf= 0.25% - 2%; r = 200)

I
I
055 - I - 1-7 - - --I - 1
O 40 50 60 70 SO 90 100 110 120 130
Flow Valr~es ('%,)
(c) Fly ash content= 40%
-
30 40 50 60 70 80 90 100 110 120 130
Flow Values (YO)
(d) Fly ash content= 60(%
I
I
I
Figo4.5(~) - (d) : Flow Values Vs WaterIBinder Ratios of Sisal Fibre Flyash - Cement Mortar
Composites (1:3 ; flyash content = 40% ,60% ; Vf= 0.25% to 2%; r = 200)

1.05 I
4 O'X
Flow Values (%)
I
I
(c) Fly ash content=70%
j(e) : Flow Values Vs WaterIBinder liatios of Sisal Fibre Flyash-Cernent I
Composites (1:3 ; flyash content = 70% ; Vf= 0.25 - 2%; r = 200)
1 Flow Value (O/O) \ I
I
I _
_ ._. _. .. ._ ^ __._
_ . ._ -- - ---.
Fig. 4.6 : Flow values Vs Water I Binder Iiatios of Flyash - Cernerlt Mortar
(1:4; flyash = 0 -70%; Vf = 0%)
I

Flow Valllc ('%,)
I
Fig. 4.7 : Flow Values Vs Water 1 Binder Ratios of Sisal Fibre Cement Conlposites
(1:4; Vf = 0.25 - 2.0%; flyash = 0%; r = 200)

I
I
0 45
20 30 40 50 60 70 SO 00 100 110 I20 130
I Flow Value (%)
(a) Fly ash content =10°/0
Flow Values (%)
(I)) Fly as11 cootcnt =20'%)
Fig. 4,8(a) - (b) : Flow Values Vs Waterminder Ratios of Sisal Fibre Flyash - Cement
Mortar Composites
(1:4 ; flyash con tent = 10 - 20% ; Vr = 0.25Oh - 2%; r = 200)

(c) Fly ash contcnt =40'!40
Flow Value ('%)
(d) Fly ash corltcnt =GO%,
Fig. 4.8(c) - (d) : Flow Values Vs WatertBinder Ratios of Sisal Fibre Flyash-Cement
Mortar Composites
(1:4 ; flyash content = 40 - 60% ; Vr= 0.25% - 2%; r = 200)

I
Flow VaSue (%)
(e) Fly ash content =70°/o
1 -
Fig. 4.8(e) : Flow Values Vs WateriBinder Ratios of Sisal Fibre Flyash-Cement Mortar
Composites
(1:4 ; flyash conterlt = 70%) ; Vr = 0.25 - 2'%,; r = 200)
Flow Value (%)
Fig.4.9 : Flow Values Vs Water 1 Binder Ratios of Flyash - Cement Mortar
(1:5; flyash = 0 - 70% ; fibre = 0% )

0.55
!
I
0.45 ,
I
20 30 ,iO 50 011 70 XI1 00 I00 1111 I30 I
Flow Valuc ('I/))
Fig.4.10 : Flow Valucs Vs Watcr I Sindcr Ratios of Sisal Fibrc Ccmcnt Composites
(15; Vr = 0.25 - 2.0%; flyash = 0%); r = 200)
20 30 40 50 60 70 80 90 100 110 120 130
Flow Value (%)
(a) Fly iis h = 1 0'%,
" Fig. 4.11(a) : Flow Values Vs WaterlBinder Ratios of Sisal Fibre Flyash-Cement Mortar
Composites
(1:5 ; flyash = 10% ; Vf= 0.25 - 2%; r = 200)

0.55
0.45 I I / ,
1
20 30 40 50 60 70 80 90 100 110 120 130
Flow Virlt~c ('%)
(b) Fly ash =20'%,
Flow Value (%)
I
I (c) Fly ash Content =40%
Fig. 4.11(b) - (c) : Flow Values Vs Water/Rinder Ratios of Sisal Fihrc
Flyasll-Cenlen t Mor-tt~r Composites
(1 :5; flyas11 = 20%) - 40'% ; Vf = 0.25 - 2%; r = 200)

Flow Value (%)
(d) Fly as11 Content = 60'%,
I
I
I
0.65 -r-- - - .-,- - -- .- -T- - - -7- I - I
20 30 40 50 60 70 80 90 100 110 120 130
Flow Value (%)
(e) Fly ash Content =70°h
I
!
Fig. 4.11(d) - (e) : Flow Values Vs Waterminder Ratios of Sisal Fibre Mortar
Flyash-Cement Composites
(1:5 ; flyash = 60% - 70% ; Vf = 0.25 - 2%; r = 200)

I
Cohesion (@a)
Fig. 4.13: Flow Values Vs Cohesion of Flyash - Cement Mortar
(1 :3 ; flyash = 0 - 70% ; Vf = 0%)
I
130 r-
I
I
I 110
1
- 100 1
' 40
I
1 301 I I I , I 1
I
10 20 30 40 50 60 70 80 00 I00 110 120 130
Cohesion (kPa)
I
Fig. 4.14 : Flow Values Vs Cohesion of Sisal Fibre Cement Mortar Composites
(1:3 ; Vf= 0.25 - 2.0% ; flyash = 0% ; r = 200)

I 40
I
i
30 I----
- r '-1- 1 - --- -- -.- --, -- -
I 10 20 30 40 50 60 70 80 90 100 110 120 130
I
Cohesion (Wa)
I
I (a) Fly ash content = 10%
l
1-
Fig. 4.15 (it) : I'low Vulucs Vs Colicsio~l of Sisi~l Fibre Flyash - Ce~llcril Mot-tar
Conlposites (1:3; flyr~sll contc~tt = 10'%, ; Vr= 0.25 - 2%; r = 200)

I
Cohesion (kPa)
Cohesion (ItPa)
1 I
I (c) Fly ash content =40% I
I
- - - -- - I
Fig. 4.15(b) - (c) : Flow Values Vs Cohesion of Sisal Fibre Flyash-Cement Mortar
Composites
(1 :3 ; flyus11 con tc11 t = 20 - 40'5) ; Vf = 0.25 - 2%; I- = 200)

40
30
20 70 JO 50 60 70 80 90 100 110 I20 110 140 150
Cohesion (kPa)
(d) Fly ash content =60%
I
I
Cohesion (kPa)
(c) Ijl, ash content =70%
Fig. 4.15(d) - (e) : Flow Values Vs Cohesion of Sisal Fibre Flyash - Cement Mortar
Composites
(1:3 ; flyash content = 60% - 70% ; Vf= 0.25% - 2%; r = 200)

Cohesion (kPa)
Fig.4.16: Flow Values Vs Cohesion of l'lyash Ccment Mortar
(1:4; flyash = 10 - 70% ; Vf = 0%)
I
i
I
I
40
30
10 20 30 40 50 60 70 80 90 100 110 120 130
Cohesion (kPa)
I
- - -- -- - I
Fig. 4.17 : Flow Values Vs Cohcsioll of Sisal Fibrc Ccmcrlt Mortar Co~nposites
(1:4; VI = 0.25 - 2.0% ; flyash = 0% ; r = 200)
1
I
I

(a) Fly ash coatcr~t =lo'%,
10 20 30 40 50 60 70 80 90 100 110 120 130 140
Cohesion (kPa)
(b) Fly ash content = 20%
Fig. 4.18(u) - (b) : Flow Values Vs Colicsioa of Sisi~l Fibrc Flyash-Cernctit Mortar
Composites
(l:4 ; flyash = 10% - 20% ; Vf= 0.25 - 2%; r = 200)

40
30
-
10 20 30 40 50 60 70 80 90 100 110 120 130 140
Cohesion (I&)
(c) Fly ash content =4Q0/;,
- --
10 20 30 40 50 60 70 80 00 100 110 120 130 140 150
I
! Cohcs ion (lil'a)
1
I
(d) Fly ash content = 60%
Fig. 4.18(c) - (d) : Flow Values Vs Cohesion of Sisal Fibre Flyash-Cement Mortar
Composites
(1:4 ; flyash content = 40 - 60% ; Vf = 0.25 - 2%; r = 200)

110
3 0
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
Cohes ion (ItPa)
I (e) Fly ash content = 70%
Fig. 4.18(c) : Flow Values Vs Cohesion of Sisal Fibre Fly:lsh-Cenmcnt Mortar
Composites
(1:4 ; flyash con terl t = 70'%, ; Vf = 0.25 - 2'%,; 1- = 200)
~ Cohesion (kPa)
1
Fig.4.19 : Flow Values Vs Cohesion of Flyas11 Ccmcnt Mortar
(1 :5; flyash = 10 - 70'% ; VVI = O'%))

Cohesion (kBa)
-.
Fig. 4.20 : Flow \/slues Vs Col~csion of Sisal Fibrc Ccn~ent Mortar Co~npositcs
(1:5; Vf = 0.25 - 2.0% ; flyash = O'YO ; r = 200)

Cohesion (kPa)
(a) Fly ash content =lo%
Cohesion (kPa)
(b) Fly ash content =20°h
...____ __ __________I---- -
Fig. 4.21(a) - (b) : Flow Values Vs Cohesion of Sisal Fibre
Flyash - Cement Mortar Composites
(l:5 ; flyesh = 10 - 20% ; Vr = 0.25 - 2%; r = 200)

40
30 I
20 30 40 50 60 70 80 90 100 110 110 130
Cohesion (kI'a)
(c) Fly ash content =40%
40 1
I
00 1
20 30 40 50 60 70 80 90 100 110 120 130 140
Cohesion (kPa)
(d) Fly ash content =6O%
- - -- --- 1
Fig. 4.21(c) - (d) : Flow Values Vs Cohesion of Sisal Fibre
Flyash - Cement Mortar Composites
(1:s ; flyl~sll = 40 - 60'%, ; Vf = 0.25 - 2%; r= 200)
I
I

120
s roo 1
V
00
- 80
70
60
50 1
h 110
$ I
I
I
I
(e) Fly ash content = 70%)
Fig. 4.21(e) : Flow Values Vs Cohesion of Sisal Fibre
Flyas11 - Cement Mortar Conlposites
(1 :S; llyilsll = 70'%, ; Vf = 0.25 - 2'%/;,; r = 200)

2 5 L o ,
+ &
E a
Y
0
- 8 a
,
2
i 2
re G
0

0 0.15 0.5 0.75 1 .O I .5 2.0
Fibre Content ('YO)
(a) Before Exposure
0 0.25 0.5 0.75 1.0 1.5 2.0
Fibrc Content ( Oh)
(b) After Exposure
Fig 4.27 (a) - (b) : Residua1 Impact Strength Ratio (I,,) Vs Fibre Contents of Sisal
Fibre Flyash -Cement Mortar Composite Slabs
(1:3; Deforc and After exposurc in NaOH; flyash = 10 - 70%)
298

0 0.25 0.5 0.75 1.0 1.5 2.0
Fibre Content (%)
(a) Before Exposure
Fibre Content (%)
(b) After Exposure
Fig 4.28 (a) - (b) : IT VS Fibre Contents of Sisal Fibre Flyash - Cements Mortar
Composite Slabs
(1:3; Before and after Exposure in NaOH; flyash = 10 - 70 %)

3 200
&
a
g I50
Conur.erc~al Type
m 20%
30%
50
0
Fibre Content (9'0)
Fig.29 : Flexural,Load Vs Fibre Contents of Sisal Fibre Flyash - Cement Mortar
Composite Corrugated ~hiets
(1:3; @ 28 days; flyash = 0 - 30%)
1 Commerc~al Type 1
ITihrc Con tcet ('%,)
Fig.30 : Splitting Load Vs Fibre Contents of Sisal Fibre Flyash -Cement Mortar
Composite Corrugated Sheets
(1:3; @ 28 days; flyash = 0 - 30%)

I Fibre Content (% ) I
Fig.4.31: Residual Impact Strength Ratio (I , ) Vs Fibre Contents of Sisal Fibre
Flyash -Cement Mortar Composite Corrugated Sheet
(1 :3; @, 22 days; flyash = 0- 301%,)
Q For Commercial Type
a 0%
El 10%
0 0.25 0.5 0.75 1.0 1.5 2.0
Fibrc Con tcn t I'%))
Fig.4.32 : Water Absorption Vs Fibre Contents of Sisal Fibre
Flyash - Cement Mortar Composite Corrugated Sheet
(1:3; @ at 28 days; flyash = 0- 30%)

1 Fibre Content (%) I 1
N - No free water on
2% the under side of
1.5% I the sheet
L - Signs of dampness
is observed
0.25%
0.00%
Commercial
(a0% flyash r 10% flyash 020% flyash 030% flyash aCommercial Type I
Fig.4.33 : Water Tightness Index Vs Fibre Contents of Sisal Fibre
Flyash -Cement Mortar Corrugated Sheet
(1:3; @. at 28 days; flyash = 0 - 30%)

(a) Cement Mortar Composite - Before Imparting Reqd. No. of Blows
(b) Cement Mortar Compsite - After Blows
Fig. 4.34 : Flow Table Test with Cement Mortar Composite
(before and after imparting reqd. no. of blows)

(a) Sheared Specimens (Front View)
(b) Sheared Specimen (Top View)
Fig.435: Photo Showing the Sheared Specimens of the Composite

(a) Plain Mortar
(b) Sisal Fibre Composites
(Vf = 0%; Fly ash = 0 -70%) (Vf = 0.25%; Fly ash = 0 -70%)
(c) Sisal Fibre Composites
(Vf = 0.5%; Fly ash = 0 -70%)
(d) Sisal Fibre Composites
(Vf = 0.75%; Fly ash = 0 -70%)
(e) Sisal Fibre Composites
(f) Sisal Fibre Composites
(Vf = 1.0%; Fly ash = 0 -70%) (Vf = 1.5%; Fly ash = 0 -70%)
(b) Sisal Fibre Composites
(Vf = 2.0%; Fly ash = 0 -70%)
Fig. 436 : Fractured Specimens of Composites Mer the Impact Test

(a) Plain Mortar
(Vf = 0%; Fly ash = 0 -70%)
(b) Sisal Fibre Composites
(Vf= 0.25%; Fly ash = 0 -70%)
(c) Sisal Fibre Composites
(Vf = 0.5%; Fly ash = 0 -70%)
(d) Sisal Fibre Composites
(Vf= 0.75%; Fly ash = 0 -70%)
(e) Sisal Fibre Composites
(Vf = 1.0%; Fly ash = 0 -70%)
(f) Sisal Fibre Composites
(Vf = 1.5%; Fly ash = 0 -70%)
(b) Sisal Fibre Composites
(Vf = 2.0%; Fly ash = 0 -70%)
Fig. 4.37: Fractured Specimens of Composites After the Flexural Test Using the
Impacted Specimens

(a) Plain Mortar
(Vf = 0%; Fly ash = 0 -70%)
@) Sisal Fibre Composites
(Vf = 0.25%; Fly ash = 0 -70%)
(c) Sisal Fibre Composites
(Vf = 0.5%; Fly ash = 0 -70%)
(d) Sisal Fibre Composites
(Vf= 0.75%; Fly ash = 0 -70%)
(e) Sisal Fibre Composites
(Vf = 1.0%; Fly ash = 0 -70%)
(f) Sisal Fibre Composites
(Vf = 1.5%; Fly ash = 0 -70%)
@) Sisal Fibre Composites
(Vf = 2.0%; Fly ash = 0 -70%)
Fig. 4B. Fractured Specimens After Evaluating the Durability of the Composite
by the Impact Test

Fig. 4.39: Fractured Specimens of Corrugated Sheet After the
Impact Test of Corrugations
(Vf = 1.0%; Fly ash = 0 -30%)
Fig. 4.40 : Fractured Specimens of Corrugated Sheet After
the Splitting Test of Corrugations
(Vc= 1.0%; Fly ash = 0 -30%)

CHAPTER 5
CONCLUSIONS
In this chapter, salient conclusions, based on the extensive experimental investigations
carriedout and the comprehensive discussion on the rheological, strength and durability
characteristics of sisal fibre cementitious composites, are presented. The relative
performance of the sisal fibre roofing sheets, has also been highlighted. A few specific
icconi~iiciiiiaLio~is bascti 011 ovc1.1111 IISSCSSI~~CI~~ i IISCSLIIIICSS of the prcscnt study, arc also
gl\~Cll.
5.2 CONCLUSIONS
Salient conclusions, based on the comprehensive experimental investigations carriedout
and on the range of various parameters considered in the present study, are sumnlarized
below.
5.2.1 Salient Fibre Characteristics
(1) The maximum water absorbed by sisal fibres is about 160% and that saturation
capacity has reached at the end of six hours itself. The above percentage of water
absorption is found to be higher than the reported value for Brazilian sisal iibres.
I Iowever, the resulting problem is overconle by adopting suitable mixing procedure to
produce composites.
('3) 'Watcr rctcntion capacity' of sisal librcs as evident lion tlic rcsulls of 'altcrnatc
wctting and drying' tcst, is ncgligiblc.
(3) There is no change in the diameter of the fibre and hence in the volume of the fibre,
when the fibres are subjected to 'alternate wetting and drying'.
5.2.2 Flyash Characteristics
(I)
Flyash obtaincd from 'lignitc osli' sourcc and ilscd in this study, has substantial
quantities of fine particlc bclow 75 and 45 microns.
(2) Flyash used, mainly conlposed of silica, alumina, iron oxides and calcium oxide
(CaO). The presence of CaO exceeding lo%, makes it to exhibit ' self hardening'
property during early age and 'pozzolanic property' during later - ages.
5.2.3 Workability of Sisal Fibre Composites
(A) At voriorrs Asl~ect Koti0.v (r = 0 -300)
1. 'Mobility' of the mortar composite, in general, is impaired by incorporation of
sisal fibres and that there is a desirable aspect ratio (of sisal fibres), beyond which,
the mobility of the mortar composites is drastically affected and hence not
desirable from practical considerations.

1). Influence of the aspect ratio and fibre content on the 'mobility' determined in
terms of flow values of all sisal fibre cement nlortar con~posites (1 :3 1 :4 and 1 :5),
is similar over the range of the above parameters considered. However, reduction
in mobility in terms of flow values for the highest aspect ratio (i.e.200 - 300) and
Iiighcst fibrc contcnt (i.e. 24) for 1 :4 and 1 :5 sisal fibsc mortar composites, are
ncarly 30'i/;, of' I :I mortar con~l>ositcs.
3. Maximum iibrc conlcnl that can be ~~sccl in thc sisal fibrc cc~iicnt mortar
composite, in case, it is intended to achieve atleast 50% of the mobility of the
reference mortar then, (i) aspect ratios less than 65 and upto 1 .O% of sisal fibres or
a maximum fibrc content of 0.5%, for aspect ratios greater than 65 for 1:3
composites; (ii) the entire range of fibre contents and aspect ratios considered in
this study, for 1 :4 and 1 :5 composites, are recommended to be adopted.
3. I.incar i,cgrcssion rcla(iansliips obtaincd for all sisal iibrc ccmciit mortar.
composites and aspcct ratios ranging fi-om 0 -300: will Iiclp to sclcct proper aspccr
ratios and fibre contents, considering the 'mobility' of the con~posites.
(13) /it Constant Aspect Ratio ( r = 200)
5. There is additional demand for water due to incorporation of flyash, to achieve i
obtain a particular flow value, for the cementitious mortar. The above phenomenon
is found to be inticpcndcnl oi'llic range of flow \~alucs considcrcd. It is found that
thc incrcusc in Wil3 ratio at masimnm Ilyas2i content (i.c. 70'M)) in the mortar. is
about 30%, 40% and 35% , higher than the W/B ratio of reference mortar, over the
range of flow values (i.e. 50 -120) and the mortar mixes (1:3, 1:4 , and 15,
respecti\lely), considered.
6. Flow behaviour of 1 :3, 1 :4 and 1:5 sisal fibre cement nlortar conlposites are
similar, under constant aspect ratio (= 200). WIB ratio required for a desired flow
valuc is 'inscnsitivc' at low fibrc contents (i.c.0.5[%) and beyond that becomes
'scnsili'i/c'. *l'hc ahovc plicnomcnon is iridcl,cntlcn( of' the range of' /low vnl~~cs
considered.
7. Increase in WiB for cement mortar composites (1:3 ; 1:4 and 15; r = 200) is
primarily due to incorporation of sisal fibres in the cement mortar. There is an
increase of abo~~t 17% in the WiB ratio of 1:3 cement mortar, at maximunl fibre
content (i.e.2.0%) to achieve a desired flow.
8. I.cancr sis;11 lihrc ccmcnt rnor~nr composites (1 :4 and 1 :5; r = 200) require about
30%0 incrcasc in WIi3 ratio ovcr the corrcspoi~ding rcfcrc~lcc morlw, at masi!i~um
fibre content (it. 2.0%) to achieve a desired flow. 111 other words, the leaner
cement mortar composites, require about 70% increase in WIB ratio over 1 :3 sisal
fibre cement mortar composites, at maximum fibre content, to achieve the desired
flow values.
9. There is a 'cumulative demand' for additional water, due to incorporation of flyash
and sisal fibres in the cementitious composites (1 :3; 1:4 and 1 :5; r = 200), for a
desired flow valuc. 'I'Iic above plie~~omcnon is fn~~nd to bc valid Ibr the range of
parameters considcrcd.
10. WIB ratio required to achieve a particular flow value is maximum, when the sisal
fibre content and flyash content in the cementitious mortar composites (1:3; 1:4
and 1:s; r = 200) are maximum (within the ranges considered). 'The average

percentage increase in WIB ratio. under the above conditions is about 47% for 1:3
cementitious composites, over the corresponding reference mortar, which is quite
substantial.
11. Leaner sisal fibre cementitious mortar co~nposites (1:4 and 1 :5; r = 200); require
;~hout 76%) and 8404 iiicrcnsc in maximum W/n ratio over tlie corresponding
I.C~~I'~IICC 111OI~1:1I'. 1 0 ;IC~~~C\'C
~);ll'li~lilili' 110~' V;I\\IC, ~lililci. idc1ilic;11 ~iII'l~lllCl~l.~ ;111d
collclilioiis. 111 olllcr wo~.ils, tlici.c is all avcr~~gc i!icscasc 01' 00 - XO'X1 innsi~iium
WIB ratio over 1 :3 cementitious mortar composites (i.e. richer con~posites), under
identical conditions.
52.4 Iihcology of' Sisal Fibrc Composites
(41) At Vnriorrs Aspect Rnfios (r = 0 - 300)
I , lillcological bchi~vioul. 01' [lit ccinciitilio~~s 1iioi.[;11. c011113ositc i.c. 'coIicsioi>' --
whicli is a measure ol'ihc 'stability' 01' tlic mortar / co~iipositc, bcars on 'invcrsc
relationship' with that of 'flow value' - which is a measure of 'mobility', over the
range of fibre contents and aspecr ratios considered.
2. Influence of fibre contents and aspect ratios on the 'stability', determined in terms
of 'cohesion values' of all sisal fibre cement mortar coniposites (1 :3, 1 :4 and 1 :5),
is similar, over the range of the above parameters considered.
3: Iliglicr coliesion valucs arc obtained wlicn tlic sisal Libre content in tlie cemcnt
mortar composite is higher, Sot. all aspcct ratios considered. Maximum cohcsion
values of 1:3, 1:4 and 1:5 cement mortar composites are almost equal and it is
about 140 kPa and attained at identical aspect ratio (i.e. 200 - 300) and fibre
content (i.e.2.0%) of the composite.
4. Highest cohesion value obtained for the 1 :3 cement mortar con~posite is about 4.4
higher than the cohesion values of the corresponding reference mortar. Even
tlioi~gli, similar behavioi~r is csliibitcd by Icancr ~iiiscs (i.c. 1 .4 tulci 1 :5 ec~iic~it
mortar composites), they liavc gaincd 0 and X times tlic cohesion valucs of' [lie
corresponding reference mortar. In other words, leaner mixes have gained higher
cohesion, when compared to the rich mix (1:3), due to incorporation of sisal fibres,
over the respective reference values of corresponding plain mortar.
5. Linear regression relatioiiships obtained for all sisal Gbrc ccment mortar
composites and covering the range of aspect ratios 0 - 300, will help to select
propcr aspect rn~ios and fibrc contcnls, considcriiig tlic ' stability' of thc
conil7osilcs.
(B) At Constanf Aspect Ratio (r = 200)
6. Rheological behaviour of 'stability' in terms of cohesion values of flyash - cement
mortar (1 :3, 1 :4 and 1 :5), with respect to flow values, flyash content in the mortar
mix and maximum cohesion value for a chosen flow value, are similar, under
identical condition.
7. Incorporation of Llynsh has con~ribu(cd lo tlic irnprovcnlcnt in thc 'stability'
i.e. cohesion values of ccmcnlitious mortar arid that thcrc is an incrcasc ol' about
2.5 times in the cohesion value of the ce~nentitious mortar, at maximum flyash
content (i.e. 70%) and the range of flow values considered. The above
phenomenon is found to the same for all the mortar mixes considered.

8, Incorporation of sisal fibres in cenlent mortar composites has contributed to
substantial enhancement in the cohesion values , irrespective of mortar mixes
considered. Cohesion value of the composite is maximum when the sisal fibre
content is maximum. The above phenomenon is found to be independent of the
range of flow values and mortar mixes considered.
9. In tcrms of percentage increase. the cohcsion values at maximum sisal fibre
co~ltclll in Lllc ccilici~l niorlai. con1lx)sitc railgcs I'l.o111 i~l~o~lt 30 -- I KO'MI, ovci Lhc
rangc of flow values considered and thc cohesion values of respective reference
mortar (i.e. 1 :3, 1 :4 and 1 :5).
10. Cohesion values of the cementitious mortar composites are ~naxinium, when the
sisal fibre contcnl ill Ilic composite is also n~axinlun~, for the range of flyash
contents considered. 'I'he above phenomenon is found to be independent of flow
values considered and also similar for all the mortar mixes (1:3, 1:4 and 1 :5),
considcrcil.
11. In terms of percentage increase: the cohesion vlues of' Ilyash - ccmcn~ mortar
composites at maxi~num flyash content (i.e. 70%) and sisal fibre content (i.e.2.0%;
r = 200) ranges from about 60 - 275% over the respective reference mortar and
over the range of flow vaii~es considered. The above trend is similar to the
bellaviour of flyash - cement mortar and cenlent mortar conlposites, under
identical conditions. There is a four - fold increase in the cohesion value of flyash
- cenicnl inol.tnl. coi~ipositcs (1 :3, 1 :4 and 1 :5), in spite of 2.5 times increase in the
lloc\ \;:rl\~cs.\vliicIi is it II~CIIICI~I~OIIS ~IIII>I.~VCIIICIII ill (IIC colirsioli v i ~ l 01' ~ i [tic ~
composite.
12. There is 'no cumulative effect' in the gain of cohesion values due to the
incorporation of flyash and sisal fibres in the cementitious composites (1:3, 1 :4 and
1 :5) which is attributed to the 'sensitivity' of flyash to water content in the mix. In
spite of the above behaviour, there is positive and substantial influence of sisal
fibres and flyash co~itents in the composite, in enl~ancing the 'stability' of the
composite.
5.2.5 Strength Behaviour of Mortar Composites
(1:3, r = 2OO;flyash = 0 - 70%; V'= 0.25% - 2.0%)
1. Compressive, flexural and split-tensile strength behaviour of sisal fibre cement
mortar composites (1 :3) and sisal fibre cementitious composites, are similar over
the range of parameters and ages (normal age i.e. at 28 days, and at later - ages
tipto 120 days), considcrcd. All tlic ahovc stscngtlis attain the i~iaxirnum al
identical Iibrc content and Ilyasli content in thc mortar composite (i.c. llyasll
content = 20%; sisal fibre content = 0.50%).
2. In case, comparable / higher strengths (compressive, flexural, split - tensile) are
desired for the cementitious composites, to / than that of reference mortar strength
(i.e. flyash = fibre content = 0%) then, the maxin~un~ flyash content be limited to
20% and the sisal fibre content to 1 .S%, in the cementitious composite.
3. 'file 'ccmentitious' and 'poozzolanic' pl.opcrtics of the Ilyash uscd havc contributcil
to the in~provement in the various strengths both at early - age and at later-ages.
Moreover, there is 'combined positive effect' of the flyash and sisal fibres, in
enhancing the performance of the mortar composites.

4. M;~sini~il~i col~ipl.cssivc strcngtli :~tlaincil I,y llic ccmcn1 mol-[ar co11ilx)silc is :lho~~t
20 MI'il j:tr$ sis~~l li1)r.c co~ltclit (VI)- 0.5(1/1,), at thc i~ormal - agc. 'l'llc itbovc
maximum strength attained by tlie cemcnt mortar conlposites (1 :3) is about 25 -
61%, higher than the plain cement mortar strength, for the range of ages
considered. The maximum long-term strength-gain ratio of the cement mortar
composite (i.e. ratio of compressive strength @ 120 days to that at normal age) is
about 2.1.
5, 14axi1~iuni conpressive strcngth attained by tlie flyash - cement mortar composite
(i.c. tlic ccilicntiliol~s Inosli11. conlposilc) is tlboilt 305 MI';\ (ctij VI. =.: 0.5'Xr; ilynsh
cr)n(c~\l 3_0'!0). itt ( I ~ c 110r111~11 ilgC. 'l'li ~I~OVC I ~ ~ ~ I X ~ IS~I.CII~~~I
I ~ L I ~ I i~ttitill~~l
~
cenientitious mortar composites, is 60 - 130% l~ighcr Illan the rel+erence mortar
strength, for the range of ages considered. The maximum long - term compressive
strength - gain ratio of the cementitious composite is about 1.9, and comparable to
thc behaviour of cement mortar composite, ilnder identical conditions.
by 111~
6. Maximum flexural strength attained by the cement mortar composite is 4.5 MPa (at
VI = 05). a1 tlic nol.nial - agc. Tlic above ~~insi~lli~ni strcngtli nt1:iincd by tlic
ccmciit nloslar composi[cs is ;~houl 30 - 50'%1 Iligl~cr than lllc rcl'crc~~cc mortar
strength and for the range of ages considered. It is Sound that the long - term
(maximum) flexural strength - ratio is nearly the same as that of the compressi~e
strength - ratio.
7. Maximum flcxural strcngth a~taincd by thc cementitious - mortar composite is
about 6.4 MPa (@ Vf = 0.5, ilyash content = 20%), at the normal - age. Maximum
flexual strength attained by tlie cementitioi~s mortar composites is 70- 1 13% higher
than tlic rcSerenc,c mol-tar st~.cngtli Tor tlic rnngc of'agcs, considcrcd. 1-ong - term
maximum strength - ratio oS the above conlposite, nearly ecjuals that of tile
strength - ratio of the composite, in compression.
8. Maxinium split - tensile strength attained by the cement mortar composite is 5.0
MPa (@ Vs =0.5), al the norn~al - agc. The above maxi~num strength attaincd by
the cement mortar composites is about 20 - 30% higher than the reference mortar
strength and for the range of ages, considered. It is found that the long- term
(masinium) split- Ic~isilc strc~~gtll ratio is 1lbo11t I .6, which is sliglitly lcss Ilii~n Lhc
other two strengths considered.
9. Maximum split - tensile strength attained by the cementitious mortar composite is
about 5.9 MPa ( @ Vf= 0.5, flyash content = 20%), at the normal - age. The above
maximum strength attained by the cemelztitious composites is about 30 - 48%
higher than the reference mortar strength, for the range of ages, considered. Long -
term (maximum) split - tensile strength - ratio of the composite is 1.6, which is
same as that or ccmcntitious composites, hilt, sliglitly less Ilinn Ilic otlicr- two
sl~~c~igtl~s, co~isidcr-ctl.
10. Ratio of the maximum split-tensile strength to tlie compressive strciigth of cement 1
cementitious mortar composites evaluated under identical conditions, is about
15% (average). The above ratio indicates once again the good performance of the
composites, under direct tension.

5.2.6 Impact Strength of Slabs: Mortar and Composite
1 . I'c~-fi)~~rl\;~r\cc ol'sisal lil~i-ccrllci~riliotik IIIOI.I;II. eoliil>ositcs i~lclt~cling
01' lhc co~i~pc'silc, caii he cvuli~;~lccl will1 case arl~l co~\lic!clicc l,y 'i.csicli~:~l irl~pacl
strength factor' (I,,) and 'llexural toughness factor' (I.i,).
[lie il~~l.i~hilily
2. Residual impact strengtli ratio (I,,) which is measure of ductility inherent in the
material ranges from 1 .I 8 to 1.74. for the cement mortar composite slabs relative
to that of the reference cement mortar slab, at normal-age and the range of sisal
fil-~rcontents considered.
in.iprovcnicnr iil tile ililc[ili~y (as 111cas~11.ccI by I,,) ol'llic
cement mortar co~uposite slabs, over thc early - age belinviour, within the range of'
later - ages considered.
- ,
. I'licrc is only a ~ni~rginal
4. Flyash - cement mortar slabs with flyash content = 20% gives a better perforniance
in terms of ductility over the cement mortar slab and flyash - cement slabs with
higher flyash contents (i.e. > 20%): under all ages considered.
5. Impiict strcngth bcliaviour of flyash - cenicnt mortar cornlositc slabs arc sinlilar to
that ol'cc~ncnl mortar conipositc slabs, at no1.11ia1 and latcl. agcs ~virli rcspcci ~o tlic
energy absorbed, and the range of flyash contents considered. I-Iowever, there is
further improvement in the energy by the cementitious composite slabs at later -
ages. The energy absorbed by the cementitious composite slab is maximum, when
the flyasll content is 20'%, for the range of fibre contents considered.
6. In ternls of residual impact strength ratio (I,,), the relative improvement in ductility
of flyash-cement mortar coniposite slabs at normal-age is 1.39 and 2.48, over the
rcfcrence mortar slab and corresponding to the niininium (0.25%) and maximum
(2.0%) fibre content and a1 optlmum flyash content (20%).
I,, is maximum and ranges from 1.81 to 2.82 (at 120 days, flyash content = 20%)
for the range of sisal fibre contents considered.
7. In case, con~parable or higher impact strength is desircd to bc achieved, for thc
flyash - cement mortar composite slab, to 1 than that of reference mortar slab at
normal and later-ages, then. the maximum flyasli content be restricted to 2044 and
the fibre con(enl to 1.5% in the cementitious composilc.
8. Impact strength behaviour has found to be greatly influenced by the combined
action of sisal fibres and the 'cementitious' and 'pozzolanic' action of the flyash
used, in enhancing the ductility of the composites, at all ages.
5.2.7 ~lexuiral Strength of Slabs: Mortar and Composite
(by fog - poi~tt Ionding metliod)
1. I'lexural strcngth bcliaviour 01' composite mortar slabs alc gcncrally s~milar to that
of standard specime~ls (of mortar and composites), within the range of paramelers
and ages considered.
2. However, the maximum strength obtained by the composite slabs are always less
( by 30% - average) than that attained by the specimens (under flexure), at all ages
considered, which may be attributed to the 'residual stress' present in the slab
spccinicns by virtue of tlic carlicr impact load sub,jcctcd on them.

5.2.8 !)urability of Sisal Fibrc Mortar Composite Slabs
I. I,, and I! valucs coiilii rcllecl Lllc clia~lgca 111 Lhc s~~,crlglIl ~ILIC 10 Llle inlc~.aclioli
between thc matrix and the medium considercii (i.c. NaOI I) and hence can be used
with confidence evaluate the durability of the mortar composites.
2. Deviation in I,, and IT values are minimum ( irrespective of the mortar 1 composite)
when the flyash content is 20% and hence it can be considered that the matrix and
the fibres are least affected when the flyash content in the composite is 2056, for all
fibre contents.
5.2.9 Sisal Fibrc Corrugatcd Rooting Sllcct
(1:3;J7L.~sh content = 0 - 30%; Vj = 0.25 - 2.0%)
1. Sisal fibre corrugated roofing sheets of (mortar i composites) couldn't match
match the high strength exhibited by thc con~mercial type corrugated roofing slieet
considered, with respect to the flexural and splitting loads and with in tile range of
sisal fibre contents (0 - 2%) and flyash contents (0 - 30%) considered in this
study
2. Flexural and splitting loads of cement mortar (1:3) and flyash - cement mortar
corrugated sheets are comparable, within the range of flyash contents (10 - 30%),
considered.
3. Incorporation of' sisal Jibres into cement mortar and flyash - cement mortar matrix
has contributed to the enhancement in the flexural and splitting loads and that the
above loads are maximum at sisal fibre content of 1.0% in the above composite
rool'shccls. over the range of' ilyash and lihrc conrcncs, considered.
3. Maximum flexural load of about 180 kg carried by the cement / cemen~itious
mortar composite corrugated sheets, is about 25% higher than the load carried by
the reference mortar roofing sheet, at sisal fibre content of 1 .O% and co~lsidering
the range of flyash and fibre contents. The above maximum flexural load is about
85% of the 'commercial type roofing sheet', tested under identical conditions.
. 5. There is tremendous improvement in the splitting load carried by of the flyash -
cement mortar composite roofing slicet and that thc above load is niasimum
(i.e. 922 N or 92.2 kg) at flyash content = 20 'Yo and sisal fibrc content = 1%. I'hc
above maximum load is about 87% of the load carried by the 'comn~ercial type
roofing sheet', evaluated under identical conditions.
6. Even though, the actual energy absorbed by the commercial type roofing sheet is
higher under the impact load, the ductility of the above roofing sheet, measured in
terms of I,, values are lower, than all mix combinations considered for the impact
studics of'thc sisal fibrc co~nposilc.
7. From the point of actual energy absorbed (i.e. at initiation of crack and a1 failure)
and ductility in terms of I,,, corrugated sheets with flyash content = 20% and sisal
fibre content = 1% in the composite, are better 1 as conlparable to that of i.e.
cement mortar corrugated sheets).
8. Flyash cement mortar composite roofing sheets (flyash = 20%; Vf = 1%) have
shown the best performance in terms of lowest water absorption (i.e. 36% lower
than comlnercial roofing sheet), and in terms of water tightness, wlien compared to

the 'commercial type' and cement mortar composite roofing sheets. The above
phenomenon is generally attributed to the imperrneabiliry imparted by the flyash to
the mortar matrix.
o!'sisi~l libre i1y;ish - ccmcnt ~nortnr
colnposilc rooling shcct ( V,. = 1%; Ilyasli contcnt = 30'!41) developed and
investigated, is co~nparable to that of a comn~ercial type roofing sheet and hence
the above product can be considered as an effective alternative to the commercial /
conventional roofing sheets, so far widely used.
0 l~'1~0111 ill1 OVCI.;~~~ ~ISSCSSIIICIIL, lii~ I~cI.~'o~I~~;~I~cc
10. However, f~~rther improvement in the performance of sisal fibre flyash - cement
mortar composite roofing sheet is possible (i) by adopting better casting
l7roccd\lses, which may incidcntnlly icnd to incorporation of higher fibrc content in
ti~ con~posito and (ii) by optimizing the sliapc and size ol'corrugations ol'the shccl
through refinement of tests and procedure for load and energy required to 'split the
corrugations'.
5.3 RECOMMENDATIONS
Following few specific reconlmendations are made from an overall assessment 1
usefulness of the present study:
(i)
The mixing procedure advocated in the study is recommended to be followed to
ensure workability, strength and durability of the natural fibre composites.
(ii) Fibre characterization and rheological studies are recommended to be adopted for
mix proportioning of natural fibre cementitious conlposites so as to achieve the
desired workability, strength characteristics and to ensure a relative durable
material1 product.
(iii) It is necessary to dcvclop il Sew licld - oricntcd and cost - cll'cctivc mctl~ods to
nleasure rheological and workability cliaracteristics of' natural fibrc ccmcn~itious
conlposites and product/(s) based on them.
5'4 SUMMARY
Based on the comprehensive experimental investigations, the importance and role of
rheological studies of natural fibre (say sisal) cementitious co~nposites in influencing their
various characteristics in wet and harclcncd statcs havc bccn b1.0~1g1it 011t C I C I I ~ I ~ 'I'lic
positive inilucncc 01' thc Ilyasli used (~vliich has both ccincnlitious and powolanic
properties) and the interaction of sisal fibres in such a matrix, which have contributed to
the enhancement various strength and durability properties of the cementitious composites,
have been highlighted. The ease and the confidence with which, certain simple tests and
procedures could help to evaluate the properties of cementitious composites, have been
presented. A few recommendations which need the attention of Professionals have been
madc.

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Cooperation), 1991.

APPENDIX

Fly ash Production and Utilization in Various Countries*
I
i Italy 01.44 00.90 I 63 1 1988 1
----
03.93 01.92 49
Nct 11cl.lu11ds - 00.74 00.72 07
-.
I-.-_
1 l'ola~~il
20.50 04.50 15 1989
I
Romania
27.00 00.70 1 03 1 1989
Russia ---
125.00 11.50 09 / 1989
South Africa 13 .00 00.58 ----
-.-
Spain
Sweden
LJI<
1 .. ...~ - ..
- 08.70
00.14
12.54
_ -.
1 lJSA , 65.1 0 --
01.22
00.08
06.12 -
15.90
Nore: I. (*) - as reporled by Clarke, L. B. (I 993)
2. Lalesr data 1701 avc~iluhle
.- 04
i 14
57
40
24
1987
----
1989 - 1989

Chemical Characteristics of 53 - Grade of Cement (IS: 12330 -1988)
max.
4 2 . 5 % man 1 4
when C3A is 1
5 or less 3% 1
mas. ~vlien
C3t2 is
: greater than
I i
.Appendix - A3
Con~positional ranges of fly ash from different countries (%) [Wesche- 19911
\
Country
I (:on1 losition ---- --
SiOz
A1 lo3
Fe 203
Compositional Ranges of Fly ash from Different Countries
Canada Dcnmarli Francc Germany Spain US,4
. 48-56
22-33
4.2- 11
- -
48-65
26-33
- - .
47-51
26-34
3.3-8.3 1 6.9-
- - --
42-55
24-33
5.4- 13
--- --
32-64 40-51
- .
21 -35 j 17-28
5.1 -2.6 8.5-19
so3
1
I
Loss on ignition
I
I
---- --- I 0,l- '0.04-1.9
I 1
I
0.2-4.0 / 0.3-
06
1 2.8
3.1-4.9 ' 05- 0.8-58 05- 10 1.2- 18
I ----
4.5

I
Appendix- A4
i
Countq
Chemical Rcquiremcnts for Flyashes in Diffcrcnt Countries [ Wesche(l991)1
Standard ,_.__ Chemical _ requirement (%)
NO. I SIC~: G- m i i i,o~
1
1 AIL:~K~~I~
- _- --
Australia AS-1 129
-----
-- 2.5 i --
Austria , ONORM \/I -- -- 1 -- 3 . 5 1 --
8.0
70 1 --
-- 15
--
1
1 DIN - r-.--
5-MX
. ...-.-- . - .
1
- .--.- .
1 Gcr~nany
~ 1045
-.-
India I.S.:3812 35 70 5 1 3 --
12 1.5 --
Japan JIS - 45 -- -- --
5
1 .0
,4620 1
-.-,-
--
'Spain"
_
1
' Turkev TS-639 -- 5 5 _-,, .._ C. i 10 -- 3
, - - I -I--- --_ --_-
I \!,I< I~S-~XO I
4 2.51 --
I___-- - . ._.
_ _. - ._I__- _ < ._ --- , 7 1.511.3 - 0.5
, ..
1 *YE -- 70/7@ 515 41J .-=I- -- ' 313 i I
US" , A S - -- 1 7 5 515 -- 16/12 -- 313
1- !
USSR
:Vote: (*I - Requiremenis for Ciass -C and Class-Ffiy ashes are indicated as value1 l value
('*) - Fir.\-/ nriti secoricl w1iie.s reprcse,i!.s for ctr~ioii on(/ corio.c/e re.s/~cc/ivel,i~
(i) S - Xi():, :1 - ;I/ :Oi , i.'- /I'(' ,,O; (11) 7j'lo I~~,~,!~~I~oIII~,!I/,s
irro /)l~.sc,ii o!i ,vj~i~c.iJic~iirori.v ;r~~c:i/ci/,/(~
!W/,
I
- -
5 I
I
1
GOST - i 40 -- -- 3 3
4269 -l-.
1
I
!ij~!r~

-
Appendix - A5
Mi~ximum residue (in (!4, rctaincd) on a
45 sieve, iis specitied in various 1nternation;il siandartls (*)
1.
2.
3.
4.
5.
6
I7
! ---
I --- --
Australla
50
Canada
34
Germany 1 50
Japan
2 5
Spain
14
II I<
I125
kj
__ S,A __ I 14
- I"__
Maximum
I type 1 I Very lligll I Very high
--- I Wide differences but less
1 rating / activily 1 inapplicable ibr use in 1
I 1 1 concrete and may cause 1
Note: The above Clirssijicurion is according to Droejc,S und reporred by Wesche (I99 1)

Categorization of Indian Flyashes Based on Particle Size
Below 1Opm (Sharrna, 1990)
' SI. ] Llange for Category
/ No. I particle size
Lime reactivity
(kg /crn2 )
Classification of Indian Filyahes Based on
LoI(Sharma, 1990)
S1.
No.
Classification
Range of
Lo1 values

.
Comparison of Compositional Ranges of the Flyash Studied with other Bndian and
International Flyashcs
Remarks
, . - -. . -. .. ~~
0 0 0 -
.- . .- .. -
Ilascil 011 I~iicr.n;~tioliaI
I
Wesche (1 99 1j
Based on Indian flyashes, 1
as reported by Chopra &
others (1 985); CRI
(1 984); Sharma (1 985);
I
13osc (1985); ClZi
( 1 970); Sh~u,n.i;~
1
+-
(1 989),Sha111a (1990)
1-18 15- 3-12 0-1 1 Based on lignlte basedash
1 1
of U.S.A and reported by
Frohnsdroff & others
10-14 1 1 - 4-4 3 --- 1 Rased on lignite - based
1 17 ' ash of the present study
1
I
Appendix - -410
Classification of Indian Flyahcs Based on
Lime - Reactivity Values (Sharma, 1990)
Classification
Range of
Lhc reactivity
1 (kg / cmz )
! I. 1 < 50% P 1
Note: Type I -for surgical plasler industr),
Type 2 -for ammonlum suiphale indusrry
Type 3 -fospotfery industry
Tvpd -for cemenl ind~rstry

I'ROCEDLIIE FOR DETEIlYllNIYG THE LENGTH, DIAMETER
NATURAL FIBRE
The length of the sisal fibre is measured by a metallic scale of ieast count oile ~nillin~eter
,411 the fibres are stretched on to the scale and ~ ls length is noted. Similarly, tile diameter of
the sisal fibre is measured by an apparatus called 'Flo~v- Technics', which is generally
used for nicasurlng the diameter of llic Lcxtilc fibres in ~cxtilc industry (or) w~tli a
~nic~orntcl (availahlc 111 s~scngth ol' mnrcrials lab of I'I:(:). I'llc d~ainctcr IS mcasu~ctl n\
four points along the length of the fibre. .A total of 50 representative salllples were
randomly selected for measuring the length and diameter of tile sisal fibres. The above two
parameters as measured are given in the Table B.l for the selected 50 samples of sisal
fibres and the coefficient of variation is arrived, both for length and diameter of the fibres.
Table B.2 Length and Diameter of Sisal Fibres in Natural Dry Condition
- I--
SI. Lcngth I)i;lmcter I Cocficicnt
I
Variation

I'ROCEDURE FOR DETERR/BlNlNG THE CHEMICAL COMPOSITIOS OF
NATVXLAL FIBRES
B 2.1 Estimation of Hemi-Cellulose
Hemi-Celluloses are non-cellulosic, non-pectic cell wall polysaccharides. They are
regarded as being composed of xylans. ~nannans, glucomannans, galacrans and
arabinogalactans. Hemi - celluloses are categorized i~nder 'unavailable carbohydrates',
sincc they are not split by the digestive enzjnles of the human syste~n.
Refluxing the salnple with a neutral detergent solution removes the water-solubles and
materials other than the fibrous component. The left out inaterial is weighed after filtration
and expressed as a neutral detergent fibre (NDI;)
!Mnteri~fs Required
I I Yo~~lial 13ctcri:cnr Sol~~lioll
I)cc

I-iern~cclli~lose = Neutral detergent fibre (NDF)- Acid detcrgcnt fibre (ADF) .. (13-1)
B 2.2 Estimation of Lignin
Lignln's are phenol~c polyrne1.s present 111 the cell walls of' planls, wh~ch arc rcspons~ble
together with cellulose, for the stiffness and rigidity of plant stems. Lignin's are especially
aisoc~atcd w~th woody planla, whercrn ~~plo 30%) of the organic maltcr of trecs consist of
lign~n L,ignin acts as a physical basrics against invading pathogens.
Principle
12cllu\11lg tlic libic pocvdc~cil s~111lplc cvlth ,rc~tl dclc~gcnr holutlon rcmovc5 tllc w,~tcisolubles
and nlaterials other than the fibrous con~ponenls l'he lei1 - out material is
weighed after filtration, dried, treated with 72% H2SO4 and filtered, dried and ashed. The
loss of weight on ignition gives the acid detergent lignin.
Materials
I Ac~il ilclci gcllt \oIii[~ol~
; !72'X> I I!SO, (\V/\l)
LJ Acetone
U Round bottom flask and refluxing set
O Muffle furnace
i-1 Sintercd glass cn~cible- G2
U Whatman No. 1 filter paper
Procedure to Find the Acid Detergent Fibre (ADF)
Take 1 g of fibre powdercd sample in a round bottom of flask with 100 ml of acid
dctcrgcnt solution. Ilcat the ahovc mixture up to boiling tcnlpcralurc for 5 to 10 rnini~tcs.
Heating should be reduced to avoid foaming as boiling begins. Reflux the lnixture for 1 hr
after the onset of boiling Adjust the boiling level to slow down to even level. Remove
contnincr, swirl and liltcr the conlcnts through a p~c L V C I ~ I I C ~ sintcrcd glass cruciblc ((3-2)
by suction and wash with hot watts ~wice. Wash w~th acctonc and brcak up the lumps.
Repeat acetone washing until the filtrate is colourless. Dry at 100' C during over noght.
Weigh the sample after cooling in a desiccator. Express ADF content in percentage as
follows.
Calculation of acid detergent fiber:
ADF = (Wo-Wt)* 100IS

Wo- wc~glit 01 i)\!ci!-iity ci\i~ibI~ ~~i~l\iiiiiig libel,
\{I,= lilt cil weight ol oven-ill q ci ~~cihlc.
S= oven-dry sample weight
Procedure to Find the Acid Detergent Lignin (ADL)
Transfer the ADF residue to lOOml beaker with 25 -50 ml of 72% sulphuric acid i.e.
I12S0,1 Allow 11 to stand fot 3 hrs w~tli ~ntcrtiiiltenlly surrlrlg cv~th a glass rod Dilute thc
,~citi wit11 d~~till~d Wiltel '~iid f'il(c1 ~ li~th j>~~c\~c~ghccI Wl~

(4) Robertson, J.B. and P.J. Van Soest.il981 j. The detergent system of analysis and ils
application to human foods: In: W.P.T.James and 0.Theander (Ed.j.The Analysis of
Dietary Fiber. pp 123 -1 58 Marcell Dekker, New York.
Soluble cellular
co~nponents
Acid-detersent extraction Hemicelluloses
1
t
( measured as
weight loss)
Acid -detergent residue
i
72% 1-hSO.q l~vdrol~sis
Cellulose (measured as
wcight loss)
Lignin,cutin,and insoluble-mineral residue
Y
KMnO,, oxida~ion
* Lignin (measured as
weight loss)
Cutin and insoluble -mineral residue
Asli at 550" ('
It Cutin weight (mcasurcd loss) as
InsolubIe-mineraI residue
Fig. B-1: Plant Cell Components in the Analytic Fractions of the Sequential
1)ctcrgcnt Systc111 of 1lol)crtson ilr~tl Vn11 SOCS~ (1081)

Appendix - C.1
Method of M~sing the Virrious Ingredients of' Natural Fibre Cenaent mortar
Ccmcnt, wnd and ilsal lib~cs here batchcci b) *c~ght and mlxlng %as done by hand
(~~iir~it ,111(l \

+
--
[sisal Fibres Cut in to Required GGh]
Wet the Sisal Fibres
for 5 n~inutcs
-- - - - - - - -- --
C
Pre weighed
I
Dry mixing of Cement ,Flyash and
Fine Aggregate
OPC, Flyash, Fine
Aggregate and Water
Abrad~ng of' Wetted Sisal fibres
1
wit11 the Dry n~ixture of above
Abraded Sisal Fibres above should
be uniformly dispcrscd manually on
thc abovc remaining dry mixturc
I
Ili~.ougl~ mixing of thc above wit11
I'rowcl for 2 to 3 minutes
.Addition of water
!
1
Pour into the moulds
T
Allow to set for 1 day
ready for
Compaction by
I-land /Vibr.ntion
Preparing the
4--
Apply release
4-- moulds
agent
I llSC
- - -
, .
1 I t
t I
Demoulding
4
Curing the Specimens
f
Testing of Specimens
Fig. C-1: Flow Chart for Preparing Sisal Fibre Cementitious Mortar

A Novel Approach for Two-Parameter Study of Cement 1 Cementitious
Composite Mortar
Sliearing strength of soil, which is defined as the resistance to sheari~zg stresses and
consequent tendency for shear deformation is an important factor for the design of slope
stability iuid foundations ol'thc sti-ucli~rcs. .411alogous to soil, cement 1 ccn~cntitious niorlar
also has shcar rcsisiancc, \.vhich is dci-ivcii by: (i) i-csistancc clue Lo iritcrlocliing of
particles; (ii) frictional resistance between the individual sand grains (due to sliding
friction, rolling friction or both); (iii) adhesion between soil particles (or) 'cohesion'.
Generally all mix proportions (i.e. from 1: 1, to 1 :6; usually adopted for structural
applications) has shear strength in wet state, due to which it is worl

.Worltabilityl of the mortar ruix in the literature. The flowability (or) niobility is less in
thc I-ichcr or composite 01. ccmcntitious or ccmcntitious composites duc to parlicit
in~erlzrcnccs in the 11iix.
Hence from the above discussion, it can be inferred that various mortar mixes can be
studied with two (different) parameters, i~amely 'cohesion' (stability of tlie mix) and 'flow
value' (mobility of the mix), with the existing conventional methods successfully. The
above two parameters indirectly affect the strength and durability of the cement
ice~iientitious composites. However, it is not possible to establish a relationship between
or. link thc ficsli arid harde~ied characteristics, in this part or tllc work. But, the above
paranleters nlay help to understand thoroughly the behaviour of the various rno~"ir mixes.

Appendix - 52.3
In the direct shear test, two types of application of shear are possible- one in which the
shear- stress is controlled (called stress - controlled shear box test) and the other, in wliich
the shear- strain is controlled (called strain - controlled shear box test). In the present
work, strain -controlled type, is adopted i.e, the shear displacement is applied at a constant
rate by means of a screw operated nianually (or) by motor. The shear force and shear
displacement is measul.cd using digiinlizcd systcm. 11-1 ihis tcst, tl~c kiilurc- planc is
piedcteri~~ii~cd which is the horizontal plane. 1)iffcrcnt samples of the same nlix arc tcstcd
under different normal loads and the results are plotted to obtain the failure envelopes. The
schematic view of the test-set - up is shown in Fig.C-2.
The salient steps involved in the test are as follows:
1. Fix the upper part. of the box to the lower part using the locking screws. Attach
the base platc to tlie lowcr part.
2. I'lace thc grid platc in the shear bos keeping thc grid at right anglcs to tlie
direction of shear. Place a porous stone over the grid plate.
3. Prepare tlie mortar for the chosen mix.
4. Place the mortar sanlplc in tlie box, tamp it gently. Fill it upto 10 to 15 rnm depth
in the top half of the shear box.
5. Place the box inside the box container, and fix the loading pad on the box. Mount
the box container on the loading frame.
6. 13ring the ~ ~ppc~. halfol'tllc hos in co11lact \villi loail ccll (2kN capacity)
7. Mourit tlic lonciing yoltc on ihc ball placed on thc loading pad.
8. Mount LVDT horizontally to measure the horizontal displace~nent (or) shear
displacement in the sample. (The vertical displaceme~it is not noted in the present
investigation).
9. Place the weights on the loading yoke to apply a normal stress of 25 k~lrnm'
10. Remove the locking screws and adjust all the values to zero.
11. Apply thc horizontal slicnr load at a constant rate of 0.5mm imin. till the
spcci~llcn ll~ils 111il I>O(C (lit SIIC;II. 1'01.c~ o~lly.
12. 12cmovc tllc sample and clcan the box ([or dry conclition) and lilt it wit11 another
sample of fresh mortar of the same mix and apply a different normal stresses of
50, 100,200,400 kh:1mm2 etc. The test observations taken for the various nixes
(i.e. 1 :3, 1 :4 and 1 :5) at different nor~nal stresses and the corresponding data for
the above lnixes are given in Table C-1 to C-3 and plots of shear stress vs. normal
stress are shown in Fig. C-3 to C-5. From the above plot, cohesion of the mix is
obtained fro171 the intercept of the graph 011 the y-axis, and reported.

~
-
Table. C-1: Shear Strength (at failure) of hlortars at Various Normal Strcsses (1:3; Flow value: 100%)
S1.
NO
1
Type of Mortar mix
Cement mortar
Shear Strength (r) kPa
1 / 2 1 3 1 4 1 5
) 2 1 Cementitious 1 74.7 1 1 0 2 . 0 ~ ~ 5 _ - 0.500 ~ 4 9
3
4
mortar
Cement mortar
Composite
(@ 1 % sisal fibre content)
Cementitious
mortar composite
(@ 1 % sisal fibre content)
. -
63.0 1 86.0 1 105.9 1 133.9 1 175.6
84.8
91.4
109.0
115.0
136.9
-
163 0
21c7
145.0 --17-0 -227.1
--
Trend Line Equation
'T = c A o tan cp7
r = 42 T 0.450
- - --
T= 59 - 0 520
--
T - 65- 0 530
Cohesion (c) Angle of Internal ]
(kpa) I Friction (cp) in degrees
44 1 24.0
Note: 1, 2,3.4,5 represents [he normal srresses of SOkPn, IOOkPo IiOkPu, ZOOkPa. 300kPa r~rpectively,
- normal stress
Tab1e.C-2: Shear Strength (at failure) of Mortars at Various Normal Stresses (1 :3; Flow value: 100°A)
-- - - . -. . - -- .
S1. Type & f s i x Shear Strength (T) ~ --
kPa Trend Line Equation Cohesion (c)
No 1 2 3 1 - 5 'T= c - rs tan cp' (kPa) -- -- Friction
.- .
1 ~%rnent mortar 73.0 108.6 144.0 179.5 250.5 T = 38 1 - 0.710 --- . 4 1
2 Cementitious 81 .S 1 17.2 152.8 188.5 259.7 r - 46 + 0.730 47
-
(cp) in depes
~
mortar
- - -- ~- .
3 Cement mortar 92.1 128.5 164.9 201.3 273.9 T = 56 + 0.730 56 36.0
Composite
(@ 1 % sisal fibre content) . ~
4 ~e~n

-
I S1. I 'I'v~e
,I
No
1
TabIe,C-3: Shear Strength (at failure) of Mortars at Various Normal Stl-esses (1:5; Flow value: 100%)
of Mortar mix 1 Shear Strength (z) kPa
-- L. ,,
I i 2 3 4 5
Cement mortar
76.7 / 112.5 148.0 - 184.0 , 255.6
1 2 ( Cementitious 1 80.0 ' 116.7 1 153.5 1 190.4 264.0
I
I mortar
--
3 1 Cement mortar
I Cdrnposite
(@I% sisal fibre content)
4 Cementitious
mortar composite
(a1% sisal fibre content)
,
98.1 j 136.0
1
173.9
Nofe: 1, 2.3.4.5 represents the nornial srresses qf j0kPa. IOUkPa, 15OkPa. .OOkPa, 3OOkPa respectivelv.
'd
2 u - normal srrers
I
21 1.8 287.6
,
Trend Linc Equation I Cohesion (c) /
'r = c + G tan cp'
r = 39 + 0.720
r = 44 + 0.730
Angle of 1nternafl
(kPa) / Friction (cp) -. in degrees
38 35.6
44 / 36.4 I
I
I

a- Motor for the desired constant rate of displacement; b- Normal Load (25,50,100,200,400 kN/mm2)
c- Shear box; d- LVDT; e- Load Cell of 2 kN ; f- Plane of Shear; g - Shear Load and Displacement indicator
Fig. C-2: Schematic View of Direct Shear Test Apparahls (Strain Control)

250
h
2 200
zi IS0
* Cernent Mottar
I
1 s Cernent~tious Mortar. ,
VI
VI 1
I
100
G
L
I
A Cement Mortar
-
50
F
U- Cornposrte (1% fibre
X~ctncnt;lioiis Mo11;ir
0 50 100 150 200 250 300 350 Colllpoiite (,%
Normal Stress (kNirn2)
content)
IGg. C:-3: Shc:br Str,css Vs. Not-~nal Stress (at Ikilur-c) o[.Varions Mortslrs
(1'3 miu; Vr= 0.5'%; 0;l;low v:tluc = 100%,)
I
+ Ccincnt bf orlar
1 1
I
El4 Ccmentitious Mortar
A C:clncriI M ortar
' Composite (1% fibre
content)
0
0
100 200 300
' X Cement~tious M ortar
Conipositc ( 1 % librc
400 content)
I'ig. ('-4: ~ltri,! St~.css Vs. No~.rnrll S(t.css (111 I'r~iiul.c) ol'Vrlrious Mol.(rll.s
(1 :4 n~ix; Vr = O.StX); I'low vall~e = 100'Y0)

A Ccncnl Mortar
Cor~iposite( 1% fibre
content), ,
x C:cncn(~l~oi~s i1x)rt;lr'
coini~ositc ill ( I '%,lillri:
colllclll)
Fig. C-5: Shear Stress Vs. Normal Stress (at failure) of Various Mortars
(1:5 mix; Vr= O.SO/O; Flow value = 100%)

Experimental Validation of the Size Effect of the Shear Box on the Cohesion Value of'
the Composite Mortar
Since tlie failure plane is predetermined in the direct box shear test, the size of this failure
plane area should be establislicd, Also tlie size effect on thc normal stress distributio~i on tlie
shear failure plane is to be investigated. The normal size of the shear box is 60 x 60 mm and
the other size of the box selected in tlie present study is 80 x 80 mm, keeping tlie thickness of
lllc spccinlc~i as sil~iic (i.c.25 111111). 'l'liis study \vi~s cal.rictio~~t i ~ t val,io~~s walcr ccmcnt ~xlio
(i.c.0.3,0.4,0.5,0.6,0.7 and 0.8) Ihs I :3 mix (plain mortal.) only. i:os ci~cli ol'thc above mixcs
and for each size of' shear box , the shear strength at failure is noted at five different normal
stresses 25. 50, 100,200, and 300 kh'/mm2 and the cohesion of each mix determined from the
plot the normal stress verses sliear stress. The cohesion of the different mortars of 1 :3 at
various WIG ratios for the two sizes of the shear boxes considered in this sti~dy is gi\ien in
Table C-4, and the variation is also shown in the form of liistogra~ns (Fig. C-6). From the
above ~.csults, it is seen that tlic si7,e of tlie specimen (i.e. sliear box) does not affect the shear
311,css i\~lil I ~ C I ~ C C lllc coli~sion 01' j l i i b nliscs. I ,:II.~cI. six ()I' (he spccitii~~i (i.c. [)ox size 80 s 80
111111) lii~s ;I (CIIIICIICY lo ~IICI.C;ISC [lie collcsioll V~I~L~CS sligiilly t111cI LIUII ~Ilc irlc~.casc ill col~csio~i
of' thc mix within 10% of the coliesion values obtained using standard box size (i.e. 60 x
60mm). Hence: it can be safely concluded that the size of specimen doesn't have any
significant influence on the coliesion of the mixes.

Table C-4: Size effect on the Cohesion of the Cement Mortar
at various W/C ratio (I :3; cement, sand ratio)
Note: (I) shear box of size 60 x 60 x 25 mm (standard size)
(2) shear box of size 80 x 80 x 25 mm
direct shear box siLe
BYd Cohesion values for
direct shear box size
WIG mtjo

Appendix - C-5
The impact as reported in this study was conducted by means of a typically fabricated
instrument. The test setup consists of two parts. One part, consist of chute like arrangement,
made up of mild steel flat mounted on four legs per~nanently with gentle slope so that the steel
ball would be ablc to roll over ii s~nootlily witliout deviating from its lincar path. The otlier
part consist of a pedestal having exactly a square in dimension (300 x 300 x 20 mm inside)
tilade up ofstccl anglcs wliicli support the spccinicn (i.c, slab) on its Sour cdgcs.
'l'lic spccilnens WCI.C ~)lil~~~i gently over rile pcilcslal, wliicl~ has becn lir~iil~, iixcd on a I-igitl
platform. The steel bail is released from the starting point of the chute which rolls under
gravity and drops / hits the centre of the slab. The dropping of the steel ball is repeated, till the
failure of the specimen. Initial and final cracks would occur due to the impact of the steel ball,
for each specimen, which were observed and noted in the observation table. The number of
blows for causing the initial and final cracks is converted into impact energy, based on the
calculated inipnct energy pcr blow for the prcsctit cxperimcntnl sct-up. The calci~lntion of
i~np;~" cti~rgy 11~1. ~ ~ I o \ Y is bric(1y iIcs~~.ib~d h~lo~li.
Computatiori of In~pcrc( Etlergv pcr Blow for a height of fall of' 'It '=2OOmm.
The transit of the steel ball through chute and on to the slab surface is shown in the Fig.C-7.
Based on the principles of Engineerina Mechanics. following are stated:
Velocity at lllc stiuting point 'A' = 0.0 ni/s
Uistance Iravclcd by llie slcel ball lion^ 'A' lo '13' i.c. 's' = 0.45 ni
Time taken by the steel bail to travel between 'A' to 'B' i.e.'t' = 2 sec.
Initial velocity at point 'B' i.e. velocity of projection, ('u') = (sit) = 0.225 mis
Maximurn height of the projcctilc path traced by the ball from the starting point 'B' = 0.2 In
When the steel ball is released from the paint 'A', runs it travels a distance of 0.45 m before it
reaches the point 'B' and then it traces a trajectory with an angle of inclination of 'a = 5.74" ',
called tile angle of projection, bcibsc it strikes the point 'C', on top surf'ace of ~lic slab. While
slcci b~ll is moving in the ~rajcc~ory, the initial vclocity '11' can bc rcsolvcd into two
components, i.e, horizontal (V,) and vertical component (V,) respectively. 'The distance
between the point of projection, i.e. 'B', and the point where the path of projectile meets and
strikes the slab surface i.e.,point 'C' is termed as the range of the projectile. The vertical
component of initial velocity is 'V, = 1 Sin(a)' and the horizontal component of the initial
velocity is 'V, = u Costa)'. Since the pro.iectile or steel ball moves in the downward direction
fronl point '0' to 'C' , the acceleration due to gravity is positive i.e. g = 9.81 rn/s2, (since tile
rnolion is towards the direction of gravity). The horizontal component of initial vclocity 'V,'
remains constant. It is assumed that the clTect of'horizontal cornponcnl on the impact energy
is very less, when compared to the vertical component.

Impact energy per blo~il ,'E'= % (rnv2lg)
where, m = mass of steel ball in I

~
Table C-5: Calibration Table for Energy per Blow
(Impact by projectile)
SI. No. 1 2 3 4 5 6 7 '
I-Ie~ghtoffall 200 250 300 350' 400 450 500
(11) in iilm
Fncrgy per
blow (Joules)
I
0.94 1 IS
1.40
I
1 63 I 86
1
2 10
I
I
Height of Fall (h) of the Steel Ball
(from point 'B' to 'C' of the Steel Ball)
Fig. C-8: Calibration Chart for the Tmpact Test Set-up
I

Appendix - C-6
CALIBRATION OF SPLIT TENSILE STRENGTH 01; CEMENT MORTAR
The results from the present novel method of finding split tensile were compared with the
method used by ACI, where the split tensile strength is determined using cylinder
specimen, so as to check the accuracy of the results and the reliability of the method
adopted, by conducting a small experiment. For the above purpose, mortar beams of size
40 x 1-10 s I00 mm ai~ri cylindcr spccirncns ol'sizc 100 illin ciia~ilctcl. 2001n1n llcigllt, cach
10 numbcrs M'CI.C cast and curcd for 28 days. l'hc niix proportion tiscd was
1:: (cen1ent:sand) at watericen~ent ratio of 0.41. Ai'rer 28 days of nonnal curing the
specimens were tested for their split - tensile strength, using the special set-up under
compression tesring machine of capacity 40t. The special set - up used for testing both the
specimens is shown in Fig.C-9. The fractured specimens are shown in Fig.C-10. For both
prism and cylinder speciineiis the split- tensile load was noted and from the (split tensile)
load split terisilc stscss is calculated as follows.
Split tensile strength of prism specimen, of,, = 0.52 j1)ia2 ) ~hrnm' . . . C-2
[as suggested by Hannant [3.39] ,and reported in the book titled: 'Concrete Technology' -
Vo1.2, By:D.F.Orchard, Applied Science Publishers Ltd., London, Fourth edition, 1979, at
pages 9 1-95]
where P = split tensile load in 'Newtons' and a = diagonal length of prism specimen in
'~nillimcters'
Split tensile strength of cylinder specimen, at, = 2 {P,' (xDh)) Ti/rnm2
. . .C-3
where P = load at split failure; D = Diameter of the cylinder; H = height of the cylinder
The split tensile strength as determined using the Eqn. C-2 and C-3, for both the
spccii~icns arc given iii Table C-6 and also shown in Fig. C-1 1. From the above results, it
c:ln be sccn that thc split tcnsilc strength are alniost equal and hence, it can bc slatcd with
conlidence that the broken piece from the flexural beam specimen (after the test) can bc
used for the split- tensile strength. This way using a single specimen (i.e, beam) it is
possible to derive thrce parameters, namely, coinpressive strength, flexural (tensile)
strength and split- tensile strength, respectively. Moreover such an approach helps in faster
experimental insestigations, using less quantity of materials, but without loss ill accuracy,
but with confidence.
Tablc C-6: Split Tcnsilc Strc~~gth of I'rism and Cylindcr Specimens (@ 28 days)
(1:3; W/C = 0.11)
S1.No.- 1 2 3 1 4 5 6 7 8 9 1101
Split Prism k\ 24 26 26 I 29 23 24 2.6 27 24
Tensile Specimen MPa 3.9 4.23 4.23 3.74 4.71 3.74 3.9
Strengdi-Cylinder
Specimen
kN
MPa
135
4.29
130
4.14
140
4.46
130
4.14
140 140
4.464.46
4.23 4.39 1 3.9 )
135' 135 130 135
4.29 4,29 4.14 4.29

D Prism Specimen 1
1 D Cylinder Specimen1
I
-Trend Line for
F'rism Specirnen
I -Trend Line for
I 1 2 3 4 5 6 7 8 9 1 0 I
No. of Tested Pieces
, Fig. C-11: Comparison of Split Tensile Strength of Prism and Cylinder ,
1 I
1 Specimens
L _ - -- - -_ - ---d
(a) Specimen Holder for
Split Tensile Strength of Mortar
(Prism Specimen)
(b) Specimen Holder for
Split Tensile Strength of Mortar
(Cylinder Specimen)
(c) Fractured Portions of Cylinder and Prism Specimens (after the test)
Fig. C-12 Experimental Investigation for Indirect Tensile Strength of Mortar
(Test set up & Specimens used)

Appendix - C-7
CAl,IRK.A'llON Oli' I'1,GXtJII:\L TFS'F SET-UI' POI< MOIITAI2 SI,AI3S
A special experimental set-up was fabricated in the laboratory to find the flexural strength
of cement i cementitious composite slab specimens. Before using the above novel method
for testing the slab specimens, the flexural strength values obtained by the conventional
method of testing of tile specimens were compared with the flexural strength values of the
same mix with the new set-up for flexural strength of mortar slabs. For the above purpose,
in the laboratory coir slab specimens of size 300 x 300 x 18 mm using 1.3 mix at W/C
ratio of 0.41 wcrc casl li>r v:~l.ious Iihrc contcllts (C)%I, 0.25'%/;,, 0.5%/;,, 0,7596, 1 .(I"/;), I .S(%
and 2%). 1;'os each ol'thc above mix and libre contents eleven slab spccimcns wcrc cast,
our of which, six slab specinlens were used for the impact test (i.e. the projectile impact
test for a fall of 200 nim) and then fractured. impacted pieces were cut the two different
sizes of slab specimens i.e. 120 x 90 x 20 mm and 120 x 135 x 20mm each of three pieces
for the respective mix. Three pieces in eacli of the nlixes were also cut for use without
subjecting them to the impact test. The experimental plan is given Table C-7 for
conti~~cting lllc ilcxiisai Icsts. I'hc cxpcrinicntal sct-ups arc shown in Fig C-13. Thc
Ilcsurul strcngth Ivits Sound hy suing I2qn.C-4 and tlic scsults obtnil~cil asc givcli in 'l'nblc
C-8. C~omparison 01' [he two rcsults is shown in thc ibrm 01' hislogriums in 1'ig.C- 14. I:som
the results it can can be stated that the novel method of finding the flexural strength of the
composite slabs yields more are less the same results as that of the conventional method of
testing slab specimens. The deviation between the t ~ sets ~ o of results is found to be within
5%. Moreover both the methods of testing (i.e, using the impacted and without impacted
specimens) yields more or less are showing the same flexural strength, which means, the
use of impacted specimens (i.e, broken pieces after impact test) doest not affect tile
Ilcsu~.al strcngtll ol'thc mortar slab spccil~icn, cluc to thc residual s~scsscs that insight havc
becn created due to impact loads, on the slabs of sizc 300 x 300 x 181~1111 during impact
testing. It is therefore possible, to derive two parameters, namely, impact strength and
flexural strength, by cast a single specimen i.e. slab (say) of size 300 x 300 x 18 mm. The
above test nlethodology has the sanic advantages as stated before, i.e. in Appendix C-6.
Flexural strength of composite mortar slab
using Soiir anti thscc point loading o =3.0864s 10-3 x P ~irnn7' ... C-4
jdcsivcd by using bending formilla i.c.
o =(Mil) y ]
Table C-7: Number of Slab Specimens Cut for Flexural Tests
SI.No. ! 1 2 1 3 4 5 6 ' 7
Fibre Content (%)
' 0 0.25 j 0.5 0.75 1.0 1.5 2.0
For without impact 3 3 1 3 3 3 3 3
' For impact 3 3 3 3 3 3 3
loading) .- ,- . . -- .-... - ...
.- ---- - - .---
- . -- . I.or with01it i:llpii;~ 3 3 1 3
For impact 3 3 3 3
Flexural Test using Novel
method (i.e. by Four point
1:lexural 'I'est using
Conventional method
(i.e.by Three point
loading)

a-span length (90mm); b- mortar slab specimen of size 120 x 135 x 18 rnrn;
c- three point loading direction
(a) Schematic View of Three - Point Loading
a-span length (90rnrn); b- mortar slab specimen of size 120 x 135 x 18 mm;
c- four point loading direction
(b) Schematic View of Four- Point Loading
Fig. C-13 : Experimental Set-up for Flexural Test of Coir Fibre Mortar Slabs

mFour-Point loildmg, not Impacted
B Four-Point loading Impacted
mThree-Pomt loadingnot Impacted
0 Three-Pomt loadvlgImpacied
Fibre Content (%)
Fig.C-14 Flexural Vs Coir Fibre Content

Appendix - C-8
'1';lblc C-9: licgr-cssion Kcliltionships for ' lilow CUI-vcs' of'Sis;il Fibre Cornpositcs
(1:4, 1:5, @ various aspect ratios)
I 1 SI.zl0. 1 Regression relationsl.lip
Correlation Range of Aspect 1
I
(R) I:5 Conzposite - A
Note: x - fibre content (%) ; y - flow value (%)
TableC-10: Regression Relationships for ' Cohesion Values' of Sisal Fibre Composites
(I :J, 1 :5,@, vv:~rio~rs ;~spcct r;~tios)
S1.No.
1
Regression relationship
(A) 1:4 Composite
y = (-) 49.21 x +13.82
y = (-) 56.144 x t17.305
y = (-) 56.263 s +21.06 .- .- - I
.L--.kl.L.
= 57.449 x -1-26.320
. - .. ..
y = (-) 60.982 x t27.587
(B) 1:5 Composite
y = (-) 44.814 x +9.730
y = (-) 49.186 x t 14.269
y = (-) 51.713 x +17.389
y = (-) 60.503 x +22.569
I
- (-1 58.863 x 1 10.70
. _-_ . i Y .- .
Correlation Range of ~ s ~ e 8
coefficient (R~) ratio (r) 1
0.95
0.95
0.96
0 .06
- - _ -
0.97
0.96
0.98
0.98
0.96
0.96
0-35 I
35-65
65-135
.+-.- i
135-200
-.-'
200-300
0-35
35-65
65-135
135-200
200-300
...I
Note: x - fibre content (%) ; y - cohesion (kPa)

[lo] Ramakrishna, G., Sundararajan,T., 'Effect of Yeast - Blended Water on The
Workability and Strength Characteristics of Sisal Fibre Reinforced Concrete', Natl.
Sem. on Advances in Construction Materials, Feb. 14 - 15, 2003, Ahmedabad,
India, pp.201-208.
[I 11 Rarnakrishna,G., Sundararajan,T., 'Strength and Workability Characteristics of
Flyash - Based Natural Fibre Reinforcd Mortar', Third IntLConf on Flyash
Utilization and Disposal, Feb. 19 -21, 2003, New Delhi, India, pp V - 27 to
V-31.
[12] Ramakrishna, G., Sundararajan , T, Manikandan, P. 'Early - age Strength
Characteristics of Coir Fibre Reinforced Concretes', Natl. Sem. on Futuristics in
Concrete & Construction Engineering (NSFCCE - 2003), Dee. 3 -5, 2003, SRM
Engg. College, Kattankulathur, Tamilnadu, India, pp. 1.36 - 1.42.
[13] Ramakrishna, G., Sundararajan , T., Suganthi, G., 'Characteristics of Ternary
Blended Sisal Fibre Composites', Natl. Sem. on Advances in Concrete Technology
and Concrete Structures for the Future, Dec. 18 - 19, 2003, Annamalainagar,
India, pp.133-140.
[14] Ramakrishna, G., Sundararajan, T., 'Impact Strength of a Few Natural Fibre
Reinforced Cement Mortar Slabs : A Comparative Study', Cement & Concrete
Composites, Vol. 27, No.5,2005, pp.554 - 564.
[15] Ramakrishna, G. and Sundrarajan, T., 'Studies on the Durability of Natural Fibres
and the Effects of Corroded Fibres on the Strength of Mortar', Cement & Concrete
Composites, Vo1.27, No.5, 2005, pp. 575 to 582.