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Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate
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Internal Curing in Cementitious Systems made using Saturated Lightweight Aggregate

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This is the presentation for my public defense of my Master's work at Purdue University on November 17th, 2008.

This is the presentation for my public defense of my Master's work at Purdue University on November 17th, 2008.

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  • 1. School of Civil Engineering Purdue University Internal Curing in Cementitious Systems Made Using Saturated Lightweight Aggregate Master‟s Defense Ryan Henkensiefken November 17th, 2008Internal Curing November 17, 2008 Slide 1 of 46
  • 2. Introduction • Lower w/c to reduce drying shrinkage • Low w/c increased autogenous shrinkage • RILEM report 41 on internal curing provides laboratory concepts • Need to move to field Neville (1995) applicationsInternal Curing November 17, 2008 Slide 2 of 46
  • 3. Objectives • Define properties of LWA that make it an effective internal curing agent • Monitor water movement from LWA to cement paste • Examine the fluid absorption characteristics of mortars • Measure the unrestrained and restrained shrinkage in sealed and unsealed conditionsInternal Curing November 17, 2008 Slide 3 of 46
  • 4. Outline • Chemical and autogenous shrinkage • Water demand – Internal void creation and drying fronts • Water supply – LWA properties, water movement and water distribution • Powers model – Influence of „internal‟ water on hydration • Fluid absorption • Role of the pore size on shrinkage • Shrinkage measurements – Unrestrained and restrained shrinkage in sealed and unsealed conditions • ConclusionsInternal Curing November 17, 2008 Slide 4 of 46
  • 5. Chemical Shrinkage • Chemical Shrinkage – Total volume reduction due to hydration – Hydration product volume is smaller than cement and water volume Chemical Cement shrinkage 1 Vol 1.8 Vol 1 Vol Hydration Water productsInternal Curing November 17, 2008 Slide 5 of 46
  • 6. Autogenous Shrinkage • Autogenous Shrinkage – External volume change in sealed conditions 0 -50 ASTM C157 -100 ) -150 Strain ( -200 -250 -300 Sealed -350 w/c = 0.30 Mortar -400 0 7 14 21 28 Age of Specimen (d)Internal Curing November 17, 2008 Slide 6 of 46
  • 7. Chemical and Autogenous Shrinkage BeforeSet After Set Vapor-Filled Chemical Voids Shrinkage = > Autogenous Autogenous Shrinkage Shrinkage = Autogenous Internal Shrinkage Autogenous Voids ShrinkageInternal Curing November 17, 2008 Slide 7 of 46
  • 8. Outline • Chemical and autogenous shrinkage • Water demand – Internal void creation and drying fronts • Water supply – LWA properties, water movement and water distribution • Powers model – Influence of „internal‟ water on hydration • Fluid absorption • Role of the pore size on shrinkage • Shrinkage measurements – Unrestrained and restrained shrinkage in sealed and unsealed conditions • ConclusionsInternal Curing November 17, 2008 Slide 8 of 46
  • 9. Water Demand 0.05 Shrinkage Volume (ml/g cement) Chemical Shrinkage Autogenous Shrinkage 0.04 From Vicat Final Set Cf CS αmax 0.03 Cf = Cement Content 0.02 Created CS = Chemical Shrinkage Void αmax = Degree of Hydration 0.01 Space Bentz, et. al, (1999) 0 0 1 2 3 4 5 6 7 Age of Specimen (d)Internal Curing November 17, 2008 Slide 9 of 46
  • 10. Sealed vs. Unsealed Conditions • Sealed conditions – Internal voids created due to chemical shrinkage • Unsealed conditions – Internal voids plus moisture front created due to drying Radlinska, et al., (2008)Internal Curing November 17, 2008 Slide 10 of 46
  • 11. Outline • Chemical and autogenous shrinkage • Water demand – Internal void creation and drying fronts • Water supply – LWA properties, water movement and water distribution • Powers model – Influence of „internal‟ water on hydration • Fluid absorption • Role of the pore size on shrinkage • Shrinkage measurements – Unrestrained and restrained shrinkage in sealed and unsealed conditions • ConclusionsInternal Curing November 17, 2008 Slide 11 of 46
  • 12. Water Supply 0.05 • Use LWA to supply additional water Chemical Shrinkage 300 Shrinkage Volume (ml/gcem) Autogenous Shrinkage • Largest pores will empty first 0.04 200 0.40 100 100 LWA-H LWA-K Percent Volume (mL/g) 0.03 0.3590 LWA-H ϕLWA LWA-K Strain ( ) MLWA × S CRCA 8 h Paste Cumulativeof Absorbed 80 Water Remaing (%) 0 0.30 24 h Paste 70 7 d Paste 0.02 -100 MLWA = Mass of LWA0.2560 S 0.2050= Degree of Saturation 0.1540 -200 0.01 25.3%k ϕLWA30 Absorption Capacity = 25.3%h 0.10 -300 20 19.4%CRCA Bentz, et. al, (1999) 0.0510 0 -400 0 1 2 3 0.00 4 0 5 6 7 1 80 82 84 86 88 90 92 10000 100000 10 100 1000 94 96 98 100 0 24 Age of Specimen (Days) Diameter (nm)(%) 48 Pore 72 Relative Humidity 96 Age of Specimen (h)Internal Curing November 17, 2008 Slide 12 of 46
  • 13. Supply vs. Demand Must Supply a sufficient volume of LWA (water) to satisfy demand in sealed conditions Demand Cf CS max Demand Supply 1 Supply M LWA S LWA Cf CS max M LWA S LWA Bentz, et. al, (1999)Internal Curing November 17, 2008 Slide 13 of 46
  • 14. Monitoring Water Movement using X-ray • Monitor density change – Volume of water changes, X-Ray Beam Source density changes • Composite theory model FOD • Timing of water release Sample FDD • Water Travel Distance ODD – Proper sample orientation Useful Beam Detector I Measured I 0 exp LWA VLWA Paste VPaste W VW V VV tInternal Curing November 17, 2008 Slide 14 of 46
  • 15. Timing of water release • LWA prism cast next to cement paste • Fixed position and macro-water movement 25 mm LWA Paste Mounting Aluminum Tape Screw Hole 2.5 mm 5 mm 25 mmInternal Curing November 17, 2008 Slide 15 of 46
  • 16. Timing of water release • Water remains in the pores of LWA until after set 0 0.05 0.000 Shrinkage Volume (ml/g cement) from Initial Counts at 3.5 h 0.04 Void Volume (mL/gcem) -0.005 -1000 Initial Difference in Counts 0.03 Set 0.02 0.01 -0.010 -2000 0 0 1 2 3 4 5 6 7 -0.015 Water is lost Age of Specimen (d) -3000 from LWA -0.020 -4000 -0.025 X-Ray Measurements -5000 -0.030 0 4 8 12 16 20 24 28 Age of Specimen (h) Counts@i,LWA – Counts@3.5,LWAInternal Curing November 17, 2008 Slide 16 of 46
  • 17. Water Distribution • Need paste within close proximity to LWA • Fine aggregate protects more paste than coarse aggregateInternal Curing November 17, 2008 Slide 17 of 46
  • 18. Monitoring Water Movement using X-ray • Monitor density change – Volume of water changes, X-Ray Beam Source density changes • Composite theory model FOD • Timing of water release Sample FDD • Water Travel Distance ODD – Proper sample orientation Useful Beam Detector I Measured I 0 exp LWA VLWA Paste VPaste W VW V VV tInternal Curing November 17, 2008 Slide 18 of 46
  • 19. Sample Orientation • Sample was Paste Paste Interface Interface rotated to correct LWA LWA orientation 0.0 mm 0.5 mm 0.0 mm 0.5 mm • Reduce the size of the „interface‟ Detector • Reduce 40000 Paste Paste Paste Interface LWA 35000 Interface Interface Uncertainty 30000 Counts (sec) 25000 LWA LWA 0.0 mm 0.5 mm 0.0 mm 0.5 mm 20000 15000 Angle of Orientation 10000 0.0 Degrees -2.5 Degrees -5.0 Degrees X-ray Source 5000 -10.0 Degrees 0 1.0 1.2 1.4 1.6 1.8 2.0Cement Paste 2.6 2.2 2.4 2.8 3.0 Position LWA (mm)Internal Curing November 17, 2008 Slide 19 of 46
  • 20. Water Travel Distance • Water is able to move approximately 1.8 mm in first 75 hours 80 – h Counts@i.Paste 7.25Counts@4.0,Paste 8.00 h 70 Difference in Counts from 9.00 h 12.00 h 60 Initial Counts (4.0 h) 24.00 h 75.00 h 50 40 Water is gained in LWA 30 the paste 20 10 0 -10 -20 -2.0 -1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 Distance from Interface (mm)Internal Curing November 17, 2008 Slide 20 of 46
  • 21. Outline • Chemical and autogenous shrinkage • Water demand – Internal void creation and drying fronts • Water supply – LWA properties, water movement and water distribution • Powers model – Influence of „internal‟ water on hydration • Fluid absorption • Role of the pore size on shrinkage • Shrinkage measurements – Unrestrained and restrained shrinkage in sealed and unsealed conditions • ConclusionsInternal Curing November 17, 2008 Slide 21 of 46
  • 22. Mixture Proportions• Constant w/c of 0.30• Constant volume fraction of fine aggregate of 55% 100 Volume Percent of Material 23% 23% 23% 23% 23% 23% 23% 23% 23% 23% Cement 80 22% 22% 22% 22% 22% 22% 22% 22% 22% 22% Water 60 12% NWA 40 55% 51% 48% 44% 41% 37% 30% 26% 22% 43.0%h 20 LWA 25.3%k/h 29.3%k 33.0%k 3.8%k 7.3%k 11.0%k 14.3%k 18.3%k 0 0 10 20 30 40 50 Percent Lightweight Aggregate of Total Mixture (%)Internal Curing November 17, 2008 Slide 22 of 46
  • 23. Powers Model Sealed 11.0 w/c of 0.30 of 0.30 % LWA w/c with 25.3 1.00 80 Chemical Shrinkage Water LWA Water Chemical Shrinkage LWA Degree ofof Hydration (%) 1 1 0.73 0.95 Maximum theoretical degree Degree Hydration (%) of hydration (w/c = 0.30) 0.90.9 70 Capillary Water Capillary Water 0.80.8 0.90 Gel Water Volume Ratio Volume Ratio Gel Water Gel Water 0.70.7 60 0.85 0.60.6 0.77 0.50.5 Gel Solid Solid Gel Gel Solid 50 0.80 0.40.4 0.30.3 0.75 25.3%k 0.240 0.2 Cement Cement Cement 11.0%k 0.10.1 0.70 0.0% 030 0 0 5 10 15 20 0.73 25 30 35 0.83 0 0 25 0.2 75 0.4 LWA-K 0.8 0 Percent 0.6 0.6 175 0.83 0.77 200 225 0.2 50 0.4 100 125 150 (%) 0.8 1 1 Age of Specimen (d) Degree ofof Hydration Degree Hydration Jensen and Hansen, 2001Internal Curing November 17, 2008 Slide 23 of 46
  • 24. Outline • Chemical and autogenous shrinkage • Water demand – Internal void creation and drying fronts • Water supply – LWA properties, water movement and water distribution • Powers model – Influence of „internal‟ water on hydration • Fluid absorption • Role of the pore size on shrinkage • Shrinkage measurements – Unrestrained and restrained shrinkage in sealed and unsealed conditions • ConclusionsInternal Curing November 17, 2008 Slide 24 of 46
  • 25. Water Absorption (10-3 gram of water / cm3 of paste) 30 55/0.35 - 28 d 55/0.30 - 28 d (10-3 gram of water /cm3 of paste) 45 (10-3 gram of water /8 cm3of paste) 25 55/0.25 - 28 d 45 (10 gram of water / cm3 of paste) 45 11.0%k - 28 d -3 gram of water / cm3 of paste) 40 45 Absorbed water at 8 days 40 Absorbed water at 8 days Absorbed water 40 Absorbed water at 8 days 25.3%k - 28 d 20 35 40 Absorbed water at days 35 35 30 35 30 30 15 25 30 25 Mortar 25 20 25 20 20 10 15 20 15 15 Plain - 28 d 5 11.0%k - 28 d 10 15 10 5 10 5 25.3%k - 28 d 5 5 10 5 5 Paste w/c = 0.30 - 28 d 1 -3 0 5 0 2 0 0 (10 0.10 0.10 0.12 0.12 0.14 0.14 0.16 0.16 0.18 0.18 0 0 0.20 0 0.30 20 0.35 40 0.40 60 10 0.25 30 50 70 80 90 100 110 120 0 Total porosity Total porosity water - cement ratio Time (min 1/2 0.10 0.12 0.14 0.16 0.18 ) excluding gel porosity excluding gel porosity Total porosity excluding gel porosity Average of 3 SamplesInternal Curing November 17, 2008 Slide 25 of 46
  • 26. ITZ Depercolation (10-3 gram of waterwater of paste) 250.10 (10-3 gram of water / cm3 of paste) 25 25 0.09 Percolated NWA ITZ Paste (Total Volume Basis) Volume Fraction 200.08 20 20 Absorbed water Absorbed / cm3 0.07 3 150.06 15 15 0.05 100.04 10 10 0.03 50.02 Cement Paste5 5 0.01 Normal Weight Aggregate -3 0.00 0 0 Lightweight Aggregate 10 15 20 25 0 0 5 30 35 0 0 1 1 2 2 3 3 4 4 5 5 0 1 Volume Percent of5 2 3 4 6 6 7 7 8 8 6 7 8 ITZ Time (d) Lightweight Aggregate Time (d) Time (d)Internal Curing November 17, 2008 Slide 26 of 46
  • 27. Outline • Chemical and autogenous shrinkage • Water demand – Internal void creation and drying fronts • Water supply – LWA properties, water movement and water distribution • Powers model – Influence of „internal‟ water on hydration • Fluid absorption • Role of the pore size on shrinkage • Shrinkage measurements – Unrestrained and restrained shrinkage in sealed and unsealed conditions • ConclusionsInternal Curing November 17, 2008 Slide 27 of 46
  • 28. Measuring Pore Size 100 98 2 Vm r Relative Humidity (%) 96 ln RH RT 94 Demand Cf CS MAX 92 M LWA Supply S LWA 90 88 86 25.3%k 84 14.3%k 7.3%k 82 0.0% 80 0 1 2 3 4 5 6 7 Age of Specimen (d)Internal Curing November 17, 2008 Slide 28 of 46
  • 29. Role of Pore Size on Shrinkage 0.30 Kelvin Radius 0.30 FromAffected Pore Region RH Pore Size From From RH Measurements % Reduction of Pore Solution Unaffected Pores Mixture Distribution 0.25 Measurements Water from 7.3%k (corrected) Shrinkage Predicted Pore Volume (ml/gcem) 0.25 Pore Volume (ml/gcem) 0.0% 7.0 5.3 Water from 14.3%k 7.0 0% Water from 25.3%k (.016 ml/gcem) 7.3%k 0.20 9.6 6.5 8.4 (.032 ml/gcem) 27% 0.20 14.3%k 11.0 7.4 (.053 ml/gcem) 9.7 36% 25.3%k 0.15 19.0 10.8 16.5 63% 0.15 Empty Pores 0.10 0.10 S 2 1 1 2 p Vm r 3 K p Ks S 2 1 1 0.05 r 0.05 p ln RH RT 3 r Kp Ks 0.00 0.00 S 2 1 1 1 1 p 10 3 r100 K p 1000 K10s 10000 100000 1000000 100 Pore Radius (nm) Pore Radius (nm) Bentz, 1998Internal Curing November 17, 2008 Slide 29 of 46
  • 30. Outline • Chemical and autogenous shrinkage • Water demand – Internal void creation and drying fronts • Water supply – LWA properties, water movement and water distribution • Powers model – Influence of „internal‟ water on hydration • Fluid absorption • Role of the pore size on shrinkage • Shrinkage measurements – Unrestrained and restrained shrinkage in sealed and unsealed conditions • ConclusionsInternal Curing November 17, 2008 Slide 30 of 46
  • 31. Unrestrained Shrinkage Procedure • Measured using corrugated tube protocol for first 24 hrs • Measured using ASTM C157 after 24 hrs Sant, et al., (2006)Internal Curing November 17, 2008 Slide 31 of 46
  • 32. Unrestrained Shrinkage in Sealed Conditions 400 Demand Cf CS 7 M LWA MAX 300 Mixtures do not Supply S LWA shrink 6 200 Age of Specimen (d) 5 Supply > Demand ) 100 Sealed Strain ( 4 33.0%k 0 29.3%k 3 25.3%k -100 Demand > Supply 18.3%k 14.3%k -200 2 11.0%k 7.3%k -300 1 0.0% -400 0 0 0 7 5 10 15 20 25 14 30 35 21 28 Percent LWA-K (%) (d) Age of Specimen Time to onset of shrinkage Average of 3 SamplesInternal Curing November 17, 2008 Slide 32 of 46
  • 33. Water Demand 0.05 Shrinkage Volume (ml/g cement) 0.05 Chemical Shrinkage 22 7 Autogenous Shrinkage Void Volume (ml/g cement) Voids Created 20 Mixtures do not 0.04 18 From Vicat 0.04 shrink Percent LWA-K (%) Final Set 6 16 Age of Specimen (d) 14.3%k 14 0.035 0.03 11.0%k 12 4 10 0.02 7.3%k 0.02 Created Time to water depletion Time to onset of 8 shrinkage 3 Void 6 0.01 3.8%k Space 4 0.01 2 2 0 0 0 10 1 2 3 4 5 6 7 0 1 2Age of Specimen (d) 3 4 5 6 7 0 Age of Specimen (d) 0 5 10 15 20 25 30 35 Percent LWA-K (%)Internal Curing November 17, 2008 Slide 33 of 46
  • 34. Unrestrained Shrinkage in Unsealed Conditions 0 400 -100 200 Cf CS Demand MAX -200 M LWA Supply S LWA 0 Strain (( )) -300 Strain -400 -200 Unsealed -500 25.3%k 33.0%k -400 11.0%k 29.3%k 0.0% -600 7.3%k 25.3%k Demand > Supply 11.0%k 0.0% 18.3%k 7.3%k Unsealed 14.3%k 0.0% -600 0.0% -700 11.0%k Sealed 0.0% 7.3%k 0.0% -800 -800 0 0 7 14 14 21 21 2828 Age of Specimen (d) Age of Specimen (d) Average of 3 SamplesInternal Curing November 17, 2008 Slide 34 of 46
  • 35. Effects of Drying 500 7 day free shrinkage (sealed) 400 7 day free shrinkage (unsealed) 300 200 ) 100 Strain ( 0 -100 -200 -300 -400 -500 0 5 10 15 20 25 30 35 Percent Lightweight Aggregate (%)Internal Curing November 17, 2008 Slide 35 of 46
  • 36. Restrained Shrinkage Procedure • Measure the cracking potentialInternal Curing November 17, 2008 Slide 36 of 46
  • 37. Restrained Shrinkage in Sealed Conditions 10 Demand C f CS MAX M LWA 30 Supply S LWA 0 Time of cracking (sealed) Mixtures did not crack -10 25 Age of Specimen (d) ) -20 20 Strain ( Sealed -30 25.3%k 15 0.0% 3.8%k 14.3%k 11.0%k -40 0.0% 11.0%k 7.3%k 10 7.3%k 3.8%k -50 3.8%k 0.0% 0.0% 5 -60 0 2 4 0 6 8 10 12 14 16 18 20 0 5 Age of15 20 25 (d) 10 Specimen 30 35 Percent LWA-K (%) Typical Response of 3 SamplesInternal Curing November 17, 2008 Slide 37 of 46
  • 38. Restrained Shrinkage in Unsealed Conditions 10 0 30 Time of cracking (unsealed) Mixtures did (sealed) Time of cracking (unsealed) not crack -10 25 Age of Specimen (d) ) Demand Cf CS MAX -20 M LWA Strain ( Supply S 20 LWA Unsealed -30 33.0%k 25.3%k 15 0.0% 29.3%k 14.3%k -40 25.3%k 11.0%k 14.3%k 7.3%k 10 11.0%k 0.0% -50 7.3%k 0.0% -60 5 0 2 4 6 8 10 12 14 0 Age of Specimen (d) 0 5 10 15 20 25 30 35 Percent LWA-K (%) Typical Response of 3 SamplesInternal Curing November 17, 2008 Slide 38 of 46
  • 39. Spatial Considerations 800 10 Sealed 43%h 0 25.3%k 600 0.0% -10 Same Volume of Water, Same Volume of Water, 400 Different Spacing Different Spacing Strain ( ) -20 Strain 200 -30 LWA-H LWA-K 0 -40 Unsealed -200 43%h -50 25.3%k 0.0% -400 -60 00 2 7 4 14 6 21 8 28 10 Age of Specimen (d) Age of Specimen (d) Typical ResponseSamples Average of 3 of 3 SamplesInternal Curing November 17, 2008 Slide 39 of 46
  • 40. Volume of Water Considerations 800 10 Sealed LWA-H LWA-K 25.3%k 0 25.3%h 600 0.0% -10 400 Strain ( ) -20 Same Volume of Aggregate, Strain 200 Different Volume of Water -30 Same Volume of Aggregate, 0 Different Volume of Water Unsealed -40 25.3%k 25.3%h -200 0.0% -50 -400 -60 00 2 7 4 14 6 21 8 28 10 Age of Specimen (d) Age of Specimen (d) Typical Response Samples Average of 3 of 3 SamplesInternal Curing November 17, 2008 Slide 40 of 46
  • 41. Conclusions • Define properties of LWA that make it an effective internal curing agent – High absorption and needs to desorb (give up) water – Pores larger than pores of cement pasteInternal Curing November 17, 2008 Slide 41 of 46
  • 42. Conclusions • Monitor water movement from LWA to cement paste – Water does not leave until after set – Water can travel up to 1.8 mm in first 75 hours 80 0 0.000 70 Difference in Counts from from Initial Counts at 3.5 h 60 Initial Counts (4.0 h) Void Volume (mL/gcem) -1000 -0.005 Difference in Counts 50 -0.010 40 LWA -2000 30 -0.015 -3000 20 -0.020 10 -4000 0 -0.025 -10 -5000 -0.030 -20 0 4 8 12 16 20 24 28 -2.0 -1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 Age of Specimen (h) Distance from Interface (mm)Internal Curing November 17, 2008 Slide 42 of 46
  • 43. Conclusions • Examine the fluid absorption characteristics – Reduce water absorption due to continued hydration or depercolate of NWA ITZ – Mixtures with LWA perform like mixtures with lower w/c (10 gram of water / cm3 of paste) 45 (10 gram of water / cm3 of paste) 45 40 Absorbed water at 8 days 40 Absorbed water at 8 days 35 35 30 30 25 25 20 20 15 15 10 10 -3 5 5 -3 0 0 0.10 0.12 0.14 0.16 0.18 0.20 0.20 0.25 0.30 0.35 0.40 Total porosity water - cement ratio excluding gel porosityInternal Curing November 17, 2008 Slide 43 of 46
  • 44. Conclusions• Measure the unrestrained and restrained shrinkage in sealed and unsealed conditions – Supply sufficient water to satisfy demand from chemical shrinkage and drying – Reduce shrinkage cracking with sufficient supply of water 500 7 day free shrinkage (sealed) 400 7 day free shrinkage (unsealed) 30 Time of cracking (sealed) Mixtures did 300 Time of cracking (unsealed) not crack 25 Age of Specimen (d) 200 ) 100 20 Strain ( 0 15 -100 -200 10 -300 5 -400 -500 0 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 Percent Lightweight Aggregate (%) Percent LWA-K (%)Internal Curing November 17, 2008 Slide 44 of 46
  • 45. Acknowledgements Professor Professor Dr. Tommy Jason Weiss John Haddock Nantung Dale Mark Janet Bentz Baker Lovell Gaurav John Jack Sant Roberts Spaulding Scott Bill Dan Katie Peter Gary Kobs Wilson Matson Funk Briatka Filbert Erin Arnd Brooks Kevin Kevin Mohammad Cutler Eberhardt Bucher Coates Gerst Pour-GhazAleksandra Kambiz Mike Mukul Chadi El JavierRadlinska Raoufi Norfleet Dehadrai Mohtar CastroInternal Curing November 17, 2008 Slide 45 of 46
  • 46. Questions Internal Curing in Cementitious Systems Made Using Saturated Lightweight Aggregate Master‟s Defense Ryan Henkensiefken November 17th, 2008Internal Curing November 17, 2008 Slide 46 of 46
  • 47. References • Bentz, D.P., Garboczi, E.J. and D.A. Quenard (1998). “Modelling drying shrinkage in reconstructed porous materials: application to porous Vycor glass,” Modelling Simulation Material Science Engineering 6: 211-236. • Bentz, D. P. and K. A. Snyder (1999). "Protected paste volume in concrete: Extension to internal curing using saturated lightweight fine aggregate." Cement and Concrete Research 29(11): 1863 • Jensen, O.M. and P.F. Hansen (2001). “Autogenous deformation and RH-change in perspective,” Cement and Concrete Research 31(12): 1859. • Neville, A.M., Properties of Concrete, Pearson Education, p. 411. • Radlinska, A., F. Rajabipour, B. Bucher, R. Henkensiefken, G. Sant, and J. Weiss, Shrinkage mitigation strategies in cementitious systems: A closer look at sealed and unsealed material behavior, in Accepted for publication in the Transportation Research Record. 2008.Internal Curing November 17, 2008 Slide 47 of 46

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