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ISSN 0974-5904, Volume 05, No. 03 (01)
June 2012, P.P. 640-643
Performance of Rice Husk Ash Concrete at Elevated Temperatures
SURYA VEERA VASUDEVA RAO. R and MANIDEEP TUMMALAPUDI
Department of Civil Engineering, GITAM University, India
Email: manitdeep@gmail.com, vasu_relangi99@yahoo.com
Abstract: In the present investigation, a feasibility study is made to utilize the Rice Husk Ash as an admixture in
concrete and to investigate the impact of elevated temperatures on compressive strength of concrete. The
proportions of water, cement, fine aggregate and coarse aggregate for M 20 grade concrete is arrived as per IS:
10262 – 2007. 5%,10%,15%and 20% of cement is replaced with rice husk ash for the study to arrive at the optimum
replacement and they are tested at room temperature ,100,300,500,700 degrees centigrade temperatures. Use of rise
husk ash in concrete not only reduces cost but also improves resistance against elevated temperatures and durability.
The utilization of Rice Husk Ash (RHA) in concrete is environmental friendly and reduces the carbon dioxide
emission.
Introduction:
Concrete is a widely used construction material for
various types of structures due to its structural stability
and strength. All the materials required for producing
such huge quantities of concrete come from the earth’s
crust. Thus, it depletes its resources every year creating
ecological strains. On the other hand, human activities
on the earth produce solid waste in considerable
quantities of over 2500/MT per year, including
industrial wastes, agricultural wastes and wastes from
rural and urban societies. Recent technological
development has shown that these materials are
valuable as inorganic and organic resources and can
produce various useful products. Amongst the solid
wastes, the most prominent ones are fly ash, blast
furnace slag, rice husk, silica fume and demolished
construction materials [1] [3].
India is a major rice producing country, and the husk
generated during milling is mostly used as a fuel in the
boilers for processing paddy, producing energy through
direct combustion and / or by gasification. About 20
million tones of RHA is produced annually. This RHA
is a great environment threat causing damage to the land
and the surrounding area in which it is dumped. In the
present investigation, cement is replaced by rice husk
ash at different percentages ranging from 0 % to 20 %
to study its effect on compressive strength. The
investigation is also aimed at to study the impact on
compressive strength of these mixes when exposed to
elevated temperatures in the range of 27 0 c to 800 0 c.
[2][4][6].
Importance of Study:
The objective of the study is to utilize the agricultural
waste produced in the world to the tune of 120 million
tones.
It reduces the consumption of cement thereby saving
raw material base, power and environment.
The focus of the present study is to investigate the
usefulness of rice husk ash concrete exposed to elevated
temperatures which is of interest for many researchers
in the recent past.
Literature review related to topic of the study Mauro M
Tashima et al. 1 studied how different grades of RHA
concrete with 5% & 10% of ash, replacing the cement,
can influence its physico-mechanical properties and
concluded that, by adding RHA a decrease in water
absorption was noted and compressive and splitting
tensile strengths showed decreasing strength by 25%
and 38.7% respectively with increase in RHA levels
when compared to control sample.
Dakroury A. El - et al. 11 explained and studied the waste
immobilization performance of (Cs+) wastes in cement
RHA mixtures and the results show that RHA addition
of 30% causes a significant increase in the hydraulic
stability of cemented waste form as RHA enhances the
strength, leaching and durability of cement .
Experimental Programme:
1.1 Materials Used:
Cement:
Cement used in the experimental work is PORTLAND
POZZOLONA CEMENT conforming to IS: 1489
(Part1)-1991. The physical properties of the cement are
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MANIDEEP TUMMALAPUDI and SURYA VEERA VASUDEVA RAO. R
641
obtained by conducting the tests specified as per IS:
269/4831 and cement confirms to the requirements as
per IS 1489-1991.
Rice Husk Ash:
Rice Husk Ash used in the present experimental study
was obtained from Orissa. General specifications,
Physical Properties and Chemical Composition of this
RHA used in this study which are furnished by the
supplier are given in Table-1, Table-2 and Table-3.
[6][7]
Fine Aggregate:
Fine aggregate (sand) used in this experimental work
confirms to zone III as per the specifications of IS 383:
1970. The Specific gravity of the Fine aggregate is
2.61.
Coarse Aggregate:
Crushed granite of 20 mm maximum size has been used
as coarse aggregate. The sieve analysis of combined
aggregates confirms to the specifications of IS 383:
1970 for graded aggregates. The specific gravity of
coarse aggregate is 2.70.
Water:
In this project potable water free from organic substance
was used for mixing as well as curing of concrete.
Super Plasticizers:
Conplast SP430A2 complies with IS: 9103 and BS:
5075 and ASTM-C-494 Type ‘G’ as a high range water
reducing admixture for obtaining a workable mix.
1.2 Mix Design for M20-Grade Concrete:
The mix proportions arrived for M 20 grade concrete
designed as per IS 10262 – 2007[8] are presented in
Table -4. Cement in proportions of 0%, 5%, 10%, 15%
and 20% is replaced with RHA.
Tests Conducted:
Standard 200 T compression testing machine is used for
testing of samples of size 100*100*100 mm which are
cast and cured for 28days,heated at different
temperatures for two hours. Specimens tested at room
temperature i.e., 27degree centigrade are used for
comparison purpose.
Three each specimens of 0%,5%,10%,15%and 20%
Rice Husk Ash replaced cubes are heated at temperature
of 27 (Room Temperature),100,300,500and700 degree
centigrade and their residual compressive strength are
tabulated. The weight gain/loss is also noted for each
sample and shown in figure below.
Bogie Hearth Furnace supplied by M/s Industrial
Furnace and Controls, Bangalore is employed to heat
specimens to different temperatures. The heated
samples are air cooled and tested for compressive
Strength.
Most concrete structures are designed assuming that
concrete processes sufficient compressive strength but
not the tensile strength. The compressive strength is the
main criterion for the purpose of structural design. To
study the strength development of Rice husk ash (RHA)
concrete at elevated temperatures in comparison to
Control concrete, compressive strength tests were
conducted at the ages of 7 and 28 days are reported as
follows.
Results and Discussions:
1.3 General:
The mix proportions along with test results presented in
Table 5. Table 6&7 illustrates Compressive strength
development of Normal concrete and Rice husk ash
concrete at different curing periods and at different
elevated temperatures. Compressive strength behavior
of RHA concrete at elevated temperature designed by
the replacement method are studied, where in the effect
of age and percentage replacement of cement with RHA
on Compressive strength is studied for M20 grade
concrete and the slump of concrete is maintained at 75
mm for all mixes.
Conclusions:
Based on the study carried out on the strength behavior
of Rice Husk Ash Replaced Concrete, the following
conclusions can be drawn:
1. Replacement of RHA in the range of 5% to 20%
does not change the compressive strength of
concrete. However, the workability decreases with
the increase in RHA replacement level. To
compensate the loss of workability super plasticizer
in the dosage of 10ml, 12ml, 14ml and 16 ml is
required for 5%, 10%, 15% and 20% RHA
replacement concrete respectively.
2. The residual compressive strength of concrete for all
the RHA replacements increases at the initial
temperatures of 100 0 c – 150 0 c and thereafter
decreases gradually upto temperature of 700 0 c
because pore water evaporates at 100 0 c and the
concrete matrix becomes brittle.
3. 15% replacement of RHA is found to be optimal as
the residual compressive strength at various
temperatures in the range of 100 – 700 degrees
centigrade shows similar strengths to that of
concrete with out RHA at 28 days(as in fig1) .
4. An overall performance of 10% RHA replacement
level at both 7 and 28 days shows better residual
compressive strength than that of normal concrete
and other replacements(as in fig1&2).
International Journal of Earth Sciences and Engineering
ISSN 0974-5904, Vol. 05, No. 03 (01), June 2012, pp. 640-643

642
Performance of Rice Husk Ash Concrete at Elevated Temperatures
5. By using this Rice husk ash in concrete as
replacement the emission of green house gases can
be decreased to a greater extent. As a result there is
greater possibility to gain more number of carbon
credits.
6. The technical and economic advantages of
incorporating Rice Husk Ash in concrete should be
exploited by the construction and rice industries,
more so for the rice growing nations of Asia.
References:
[1] P.ChandanKumar and P.MalleswaraRao, “A Study
on Reuse of Rice Husk Ash in Concrete”, Pollution
Research ,29 (1), 2010, pp157-163 .
[2] P.Kumar Mehta, “Concrete Technology for
Sustainable Development,” Concrete International,
November 1999, pp.47-53.
[3] P.Kumar Mehta, “Reducing the Environmental
Impact of Concrete,” Concrete International,
October 2001, pp.61-66.
[4] Min-Hong Zhang and V. Mohan Malhotra, “High-
Performance Concrete Incorporating Rice Husk
Ash as a Supplementary Cementing Material,” ACI
Materials Journal, November-December 1996,
pp.629-636.
[5] Mauro M. Tashima, Carlos A. R Da Silva, Jorge L.
Akasaki, and Michele Beniti Barbosa, “The
Possibility of adding the Rice Husk Ash (RHA) to
the Concrete,” Conference, FEIS/UNESP, Brazil
2001
[6] G.V.Rama Rao and M.V.Sheshagiri Rao,”High
performance Concrete with Rice Husk Ash as
Mineral Admixture,”ICI Journal, April-June 2003,
pp.17-22.
[7] Rama Rao G.V and Seshagiri Rao M.V (2004)
”High Performance Concrete Mix Design using
Husk Ash As Mineral Admixture”, proceedings of
national conference on materials and structures,
Warangal, pp.65-70.
[8] Rama Samy and Dr. Viswa. S (oct-dec,2009)
“Durable To Properties Of Rice Husk Ash
Concrete”, ICI journal Indian concrete institute pp.
41-50.
[9] IS 10262-2009: Indian Standard Concrete Mix
Proportioning-Guidelines, Bureau Of Indian
Standards,2009, New Delhi.
[10] In this paper Moayad N. AlKhalaf et al., the effect
of rice husk ash content as partial replacement of
cement on compressive strength and volume
changes of different mixes is only investigated.
Table 1: Specifications of Rice Husk Ash
Silica
Humidity
Mean Particle Size
Color
Loss on Ignition at
800 0 C
Table 4: Mix Proprotions for M20 Grade Concrete
90% minimum
2% maximum
25 microns
Grey
4% maximum
Table 2: Physical Properties of Rice Husk Ash
Physical State Solid – Non Hazardous
Appearance Very fine powder
Particle Size 25 microns – mean
Color
Grey
Odour
Odourless
Specific Gravity 2.3
Table 3: Chemical Properties of Rice Husk Ash
SiO 2 93.80%
Al 2 O 3 0.74%
Fe 2 O 3 0.30%
TiO 2 0.10%
CaO 0.89%
MgO 0.32%
Na 2 O 0.28%
K 2 O 0.12%
Loi 3.37%
Water Cement Fine Aggregate Coarse Aggregate
191.61 /m 3 383 kg 594kg 1356 kg
0.5 1 1.55 3.54
Table 5: Mix Proportion of Rice Husk Concrete for 0%, 5%, 10%, 15%&20% Replacement
Grade of
Concrete
Cement
in Kgs
Rice Husk
Ash in Kgs
Fine
Aggregate
in Kgs
Coarse
Aggregate
in Kgs
Water
in Ltrs
Super
Plasticizer
in ml
M20(0%) 1 0 1.55 3.54 0.5 -
M20(5%) 0.95 0.05 1.55 3.54 0.5 10
M20(10%) 0.9 0.1 1.55 3.54 0.5 12
M20(15%) 0.85 0.15 1.55 3.54 0.5 14
M20(20%) 0.8 0.2 1.55 3.54 0.5 16
International Journal of Earth Sciences and Engineering
ISSN 0974-5904, Vol. 05, No. 03 (01), June 2012, pp. 640-643

MANIDEEP TUMMALAPUDI and SURYA VEERA VASUDEVA RAO. R
643
Table 6: Compressive Strength at different Temperatures for different RHA Replacements at 7 Days
Table 7: Compressive Strength at different Temperatures for different RHA Replacements at 28 Days
Temperature Compressive Strength in N/mm 2
RHA Replacement ->% 0 5 10 15 20
27 0 c 34.49 36.38 38.2 34.01 30.45
100 0 c 35.69 37.39 39.65 35.28 31.45
300 0 c 32.4 33.4 36.9 31.12 27.9
500 0 c 28.84 29.8 31.47 28.09 24.36
700 0 c 25.99 26.75 27.8 24.65 23.7
Figure 1:
Figure 2:
International Journal of Earth Sciences and Engineering
ISSN 0974-5904, Vol. 05, No. 03 (01), June 2012, pp. 640-643