1. Volume Changes of Concrete Design and Control of Concrete Mixtures – Chapter 10

2. Overview Early age volume changes Moisture changes Temperature changes Curling and warping Elastic and inelastic deformation Creep Chemical changes and effects

3. Volume Changes of Concrete Many reasons for volume changes Understanding volume changes is useful Restraint of volume changes leads to cracking

4. Early Age Volume Changes

5. Chemical Shrinkage

6. Autogenous Shrinkage

7. Subsidence Vertical shrinkage before initial set Caused by bleeding, escaping air, and chemical shrinkage May be a symptom of lack of consolidation May lead to cracking over embedments

8. Plastic Shrinkage Cracking

9. Swelling

10. Moisture Changes of Hardened Concrete

11. Moisture Changes

17. Moisture Changes – Effect of Materials

19. Aggregates restrain shrinkage Second greatest influence behind total water content Quartz, granite, feldspar, limestone, and dolomite produce lower shrinkage

20. Moisture Changes – Effect of Materials

21. Moisture Changes – Effect of Curing

22. Temperature Changes of Hardened Concrete Concrete expands as temperature rises Average value about 10 millionths per degree Celsius (5.5 millions per degree Fahrenheit) Range: 6-13 millionths/degree Celsius (3.2-7.0 millionths/degree Fahrenheit)

23. Temperature Changes

25. Temperature Changes – Low Temps Subfreezing volume changes depend on moisture content and behavior, aggregate type Low temperatures also increase strength of moist concrete---little effect on dry concrete

26. Temperature Changes – High Temps

28. Curling and Warping

29. Elastic and Inelastic Deformation

30. Elastic/Inelastic Deformation

31. Poisson’s Ratio

32. Shear and Torsional Strain

33. Creep

37. Chemical Changes and Effects Carbonation shrinkage Sulfate expansion Alkali-aggregate expansion

38. Summary Early age volume changes Moisture changes Temperature changes Curling and warping Elastic and inelastic deformation Creep Chemical changes and effects

39. Questions