1. Cement Production

2. Portland Cement By definition — a hydraulic cement produced by pulverizing clinker consisting essentially of hydraulic calcium silicates, usually containing one or more of the forms of calcium sulfate as an interground addition

3. Source: PCA, 2003

4. Raw Materials Necessary for Portland Cement Manufacture Must Provide the Following • Calcium • Silica • Alumina • Iron Hydraulic binders, Latent hydraulic binders, pozzolanic materials, inert materials

5. Source: PCA, 2003

6. Traditional Manufacture of Portland Cement 1. Stone is first reduced to 125 mm (5 in.) size, then to <19 mm (3/4 in.), and stored. Source: PCA, 2003

8. Raw materials are ground to powder and blended. or 2. Raw materials are ground, mixed with water to form slurry, and blended. Source: PCA, 2003

9. 3. Burning changes raw mix chemically into cement clinker. Source: PCA, 2003

10. Source: Mindess, Young, and Darwin, 2004

11. Source: Mindess, Young, & Darwin, 2004

12. 3. Burning changes raw mix chemically into clinker. Note four stage preheater, flash furnaces, and shorter kiln. Source: PCA, 2003

13. Pyro- Processing

15. Source: PCA, 2003

16. 4. Clinker is ground with gypsum into portland cement and shipped. Source: PCA, 2003

17. Clinker Gypsum Source: PCA, 2003

18. Grinding • Clinker is ground with gypsum (calcium sulfate) to produce portland cement • Fine grinding is necessary for high early strength • 85-95% -325 mesh (45 microns) • ~ 7 trillion particles per pound • Gypsum absorbs water and prevents setting of C3A during shipment

19. Source: van Oss and Padovani, 2002

20. Process of Clinker Production Source: PCA, 2003

21. Source: PCA, 2003

22. Source: PCA, 2003

23. Source: Taylor, 1997

24. Source: MacLaren and White, 2003

25. Source: MacLaren and White, 2003

26. Clinker Phases • Alite or 3CaO•SiO2or C3S • Hydrates & hardens quickly • High early strength • Higher heat of hydration (setting) • Belite or 2CaO• SiO2or C2S • Hydrates & hardens slower than alite • Gives off less heat • High late strength (> 7 days) • Modern cements are manufactured to be higher in alite for early strength

27. Clinker Phases • Aluminate or 3CaO• Al2O3or C3A • Very high heat of hydration • Some contribution to early strength • Low C3A for sulfate resistance • Ferriteor4CaO• Al2O3 • Fe2O3orC4AF • Little contribution to strength • Lowers clinkering temperature • Controls the color of cement

28. Microscopic Images of Clinker

29. Microscopic Images of Clinker Alite

30. Microscopic Images of Clinker Belite

31. Microscopic Images of Clinker Aluminate

32. Microscopic Images of Clinker Ferrite

33. Types of Portland Cement ASTM C 150 (AASHTO M 85) I Normal II Moderate sulfate resistance III High early strength IV Low heat of hydration V High sulfate resistance

34. Source: Mindess, Young, and Darwin, 2004

35. Source: Mindess, Young, and Darwin, 2004

36. Source: Mindess, Young, and Darwin, 2004

37. Source: Mindess, Young, and Darwin, 2004