Lightweight Concrete for High Strength - Expanded Shale & Clay

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NOTATION Report ACI 318- 99 AASHTO Standard Description a -- -- Shear span, distance from support to point load on girder A c -- -- Cross sectional area of composite girder (combined area of girder and deck) A nc -- -- Cross sectional area of girder AASHTO -- -- American Association of State Highway and Transportation Officials A ps A ps A s * Cross sectional area of prestressing strand A pse -- -- Effective area of prestressed reinforcement adjusted inside the transfer or development length regions A v A v A v Area of shear (stirrup) reinforcement BCL -- -- Distance from bottom of girder to center line of bottom row of prestressing strands CM -- -- Cementitious Materials CSS -- -- Concrete Surface Strain DAQ -- -- Data Acquisition d b d b D Diameter of prestressing strand DEMEC -- -- Detachable Mechanical Strain Gage d p d p d Distance from compression fiber to centroid of prestressed reinforcement E c E c E c Modulus of elasticity of concrete based on 6 x 12 cylinder E ci -- -- Modulus of elasticity of concrete based on 6 x 12 cylinder at strand release Elastic modulus of prestressing steel (ksi) E ps f c ’ f c ’ f c ’ Concrete compressive strength at specified time f ci ' f ci ' f ci ' Concrete compressive strength at strand release f d f d Tensile stress at the extreme tensile fiber due to the dead load of the girder and slab f cds stress in concrete at the cgs due to all superimposed dead loads (ksi) f r f r f r Modulus of rupture of concrete f pc f pc f pc Resultant compressive stress at the centroid of the composite section or at the junction of the web and flange when the centroid lies within the flange due to both prestress and moments resisted by the precast member acting alone. Compressive stress at the extreme tensile fiber due to effective f pe f pe prestressing force f ps f ps f su * Stress in prestressed reinforcement at nominal strength of member vii
Report ACI 318- 99 AASHTO Standard Description f pt -- -- Stress in prestressing strand just prior to strand release f pu f pu f s ’ Specified tensile strength of prestressed reinforcement f se f se f se Effective prestressing stress after losses f si -- -- Stress in prestressing strand just after strand release f su Stress in prestressed reinforcement at nominal strength of member f y f y f sy Specified yield strength of non-prestressed reinforcement h h h Overall depth of the composite girder; Also used as relative humidity for shrinkage calculations I c -- -- Moment of inertia of composite girder (girder and deck) I nc -- -- Moment of inertia of girder l d l d -- l fb -- -- Development length of prestressing strand (In AASHTO Standard, l d refers to non-prestressed reinforcement development length) Flexural bond length. Additional length over which the strand should be bonded so the stress f ps may develop in the strand at the nominal strength of the member. l t -- -- Transfer length of prestressing strand LOLAX -- -- Low relaxation loss prestressing strand M DL -- -- Moment due to Dead Load n n -- Modular Ratio s s s Spacing of shear reinforcement S Beam or specimen surface area (in 2 ) S top-nc -- -- Top section modulus for non-composite girder S bot-nc -- -- Bottom section modulus of non-composite girder S top-c -- -- Top section modulus for composite girder S bot-c -- -- Bottom section modulus for composite girder t age of concrete (days) for creep and shrinkage calculations t’ age of concrete at loading (days) for creep and shrinkage calculations TCL -- -- Distance from top of girder to center line of top row of prestressing strands W/CM -- -- Water to Cementitious Materials Ratio w c w c w c Unit weight of concrete V Beam or specimen volume (in 3 ) V c V c V c Nominal shear strength provided by concrete V ci V ci V ci Nominal shear strength provided by concrete when diagonal cracking results from combined shear and moment V cw V cw V cw Nominal shear strength provided by concrete when diagonal cracking results from excessive principal tensile stress in the web viii
Page 1 and 2: School of Civil and Environmental E
Page 3 and 4: ACKNOWLEDGMENTS The research presen
Page 5 and 6: A statistical evaluation based on f
Page 7: 5.6 - Transfer Length 5-13 5.7 - Gi
Page 11 and 12: Chapter 1. Introduction 1.1 Purpose
Page 13 and 14: Long term properties including pret
Page 15 and 16: ottom flange. Prestressing strands
Page 17 and 18: 12500 12000 Concrete Strength, fc'
Page 19 and 20: Chapter 3. Mix Designs, Field Evalu
Page 21 and 22: Variation of coarse-to-fine aggrega
Page 23 and 24: 3.2.1 Compressive Strength Figure 3
Page 25 and 26: Table 3.5 Chloride Permeability --
Page 27 and 28: 12,000 11,500 11,000 Compressive St
Page 29 and 30: 1,400 1,300 1,200 1,100 Experimenta
Page 31 and 32: strength (10L made in the laborator
Page 33 and 34: The 50% and 90% of the 620-day cree
Page 35 and 36: 700 600 10,000-psi Measured Shams &
Page 37 and 38: a Creep Coefficient 3.0 2.5 2.0 1.5
Page 39 and 40: Chapter 5. Behavior of AASHTO Type
Page 41 and 42: Portion of Girder Damaged During Te
Page 43 and 44: 2” End Cover (Typ both ends) 4 Sp
Page 45 and 46: 5.3 Instrumentation The surface of
Page 47 and 48: Figure 5.7 Installation of stirrups
Page 49 and 50: Table 5.3 Girder concrete propertie
Page 51 and 52: 120 100 80 Stress (ksi) 60 40 20 0
Page 53 and 54: Table 5.5 -Transfer Length Results
Page 55 and 56: Figure 5.12 Typical flexural failur
Page 57 and 58: Since G2 girders had a higher concr
Page 59 and 60:
V " pc cw− Pr ed = ft −Pr ed 1
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Test # Table 5.9 Predicted vs. Expe
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this research project, modification
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Chapter 6. Prestress Losses in HPLC
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losses in the 10,000-psi girders to
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Microstrains (in/inx10 -6 ) 0 500 1
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6.3 Conclusions Regarding Prestress
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7.3 Transfer Length An evaluation o
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Shrinkage after 620 days of drying
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More research is required to examin
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Appendix A. Background A.1 Introduc
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Raithby and Lydon described the use
Page 83 and 84:
are normally recognized as being on
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aggregate must be saturated by pres
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A.7.2 Strength Ceiling Harmon discu
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compared to lower strength specimen
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A.8.8 Deatherage, Burdette and Chew
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3. Concrete compressive strength at
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findings were comments that the AAS
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including strand diameter, embedmen
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l d = l t + l fb = f si 3 d b + 1.5
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l d = l t + l fb ⎛ = ⎜ ⎝ f d
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Table A.1 Summary of Development Le
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strand release, the strand attempts
Page 107 and 108:
Appendix B. Creep and Shrinkage B.1
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Changes in moisture migration: the
Page 111 and 112:
t′: age of concrete at loading (d
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s: slump (in) γ ψ ⎧ 0.30 −1.4
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t: age of concrete (days) t 0 : age
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where ε sh ∞ ⎧ 510 µε for st
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left girder-end. The dimension L wa
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6” 85” 50” Segment of girder
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146” 89” 96” 137” Stirrups
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were added in a specific sequence f
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C.2.3 Formwork Removal, Detensionin
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Figure C.19 Mostafa Prestressing St
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Figure C.22 Ms. Lyn Clements (GDOT)
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If significant strand end slip over
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CSS at Level of Bottom Strands (µ
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Appendix D. Prestress Losses in HPL
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E ps : elastic modulus of prestress
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D.2.2. AASHTO-LRFD Refined Estimate
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∆f log(24 ⋅t) ⎛ f ⎜ ⎞ 55
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P i : initial prestressing force af
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References AASHTO (1996), Standard
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ASTM C 618, Standard Specification
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Guide for Structural Lightweight Ag
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Martin, L. D., Scott, N. L., “Dev
Page 155:
Shahawy, M. A., Batchelor, B., “S
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Lightweight Concrete for High Strength - Expanded Shale & Clay

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