1. Supplementary Cementitious Materials Design and Control of Concrete Mixtures – Chapter 4

2. Overview Fly ash Slag cement Silica fume Natural pozzolans Reactions Effects on concrete Proportioning

3. Supplementary Cementitious Materials

5. SCM Properties

6. Fly Ash

7. ASTM C618 Class F  Pozzolanic  SiO 2 + Al 2 O 3 + Fe 2 O 3 ≥ 70% Class C  Pozzolanic with some hydraulic behavior  SiO 2 + Al 2 O 3 + Fe 2 O 3 ≥ 50%

8. Fly Ash – Physical Properties

9. Slag Cement

10. ASTM C989 Grade 80 Grade 100 Grade 120

11. Slag Cement

12. Silica Fume

13. ASTM C1240 As-produced Slurry Densified Up to 99% silica content

14. Silica Fume

15. Natural Pozzolans ASTM C618, Class N Calcined shale Calcined clay Volcanic ash

16. Natural Pozzolans

17. Metakaolin

18. Pozzolanic Reactions Pozzolan + CH = C-S-H Different from portland cement C-S-H Contribute to strength Reduces permeability

19. Hydraulic Reactions Slag cement and some pozzolans with high calcium contents No calcium hydroxide byproduct; may consume calcium hydroxide from system Reactivity dependant on fineness and composition of slag cement, temperature, and alkali content of portland cement

20. Effects on Freshly Mixed Concrete

21. Water Demand

22. Workability Increases Fly ash Slag cement Calcined shale and clay Decreases Silica fume Metakaolin

23. Bleeding and Segregation

24. Setting Time

25. Air Content SCMs generally require more air-entraining admixture Effect of fly ash dependent on carbon content, fineness, alkali content Effect of slag cement is minimal; caused by fineness Effect of silica fume is significant due to fineness

26. Heat of Hydration

27. Effects on Hardened Concrete

28. Strength (Whiting 1989).

29. Strength (Detwiler 2000).

30. Impact and Abrasion Resistance (Gebler and Klieger 1986)

31. Permeability and Absorption SCMs generally reduce permeability and absorption Silica fume and metakaolin significantly reduce permeability and absorption Increased corrosion resistance

32. Alkali-Silica Reactivity (Detwiler 2002)

33. Alkali-Silica Reactivity (Lerch 1950).

34. Alkali-Silica Reactivity (Thomas 2007).

35. Sulfate Resistance SCMs improve sulfate resistance Fly ash: Class F better than Class C Calcined clay: better than Type V portland cement

36. Deicer-Scaling Resistance

37. (After Whiting 1989).

38. Deicer-Scaling Resistance (Whiting 1989).

39. Deicer-Scaling Resistance

40. Concrete Mixture Proportions Optimums determined by testing Ternary/Quaternary systems Synergy between SCMS  Fly ash offsets silica fume workability issues  Silica fume compensates for low early-strength of fly ash

41. Summary Fly ash Slag cement Silica fume Natural pozzolans Reactions Effects on concrete Proportioning

42. Questions