High strength cement, mortar and concrete including industrial by-products
Cementitious compositions in which the cementitious properties of fly-ash are carefully controlled. The cementitious compositions may be substantially free harsh acids and bases such as citric acids (≈pH 2.2) and alkali metal activators including alkali hydroxides (≈pH 12-14) and metal carbonates (≈pH 11.6). The use of these harsh chemicals creates acid base reactions during use of the products. Instead of these harsh chemicals, a citric salt, for example potassium citrate, may be used as a reaction accelerator. Boric compounds may be used as a retarder in the compositions.
1. A hydratable cement comprising:
a pozzolan powder;
one or more pH neutral activators; and
a retarder,
wherein the hydratable cement has a calcium content expressed as the oxides of 15 wt % or more based on the total weight of the hydratable cement, and
wherein the pH neutral activators account for greater than 50% of the total weight of activators in said hydratable cement; and
wherein the hydratable cement has less than 20% by weight Portland cement based on the total weight of the hydratable cement.
2. A hydratable cement according to claim 1 comprising a citrate salt activator, and wherein said citrate salt activator comprises greater than 95% of the total weight of activators in said hydratable cement.
3. A hydratable cement according to claim 1 comprising Portland cement in an amount less than 15% by weight based on the total weight of the hydratable cement.
4. A hydratable cement according to claim 1 that is substantially free of Portland cement.
5. A hydratable cement according to claim 1 wherein the hydratable cement has a calcium content expressed as the oxides of 20 wt % or more based on the total weight of the hydratable cement.
6. The hydratable cement of claim 1 wherein the calcia to silica molar ratio is between about 1.2:1 and about 1.4:1.
7. The hydratable cement of claim 1 , wherein the pozzolan powder is selected from the group consisting of Class C fly-ash, Class F fly-ash, Class N pozzolanic ash and combinations thereof.
8. The hydratable cement of claim 1 , wherein the pozzolan powder consists essentially of Class C fly-ash and Class F fly-ash, wherein the Class C fly-ash is present in an amount of 50-80 weight percent, and the Class F fly-ash is present in an amount of 10-30 weight percent based on the total weight of the hydratable cement.
9. The hydratable cement of claim 1 , further comprising a calcium-rich material additive.
10. The hydratable cement of claim 9 , wherein said calcium-rich material comprises an industrial byproduct selected from the group consisting of cement kiln dust, lime kiln dust, furnace slag, scrubber ash, and combinations thereof.
11. The hydratable cement of claim 1 , wherein the pozzolan powder consists essentially of Class C fly-ash.
12. The hydratable cement of claim 1 , comprising 50 to 95 weight percent Class C fly-ash based on the total weight of the hydratable cement.
13. The hydratable cement of claim 1 , wherein the pozzolan powder consists essentially of Class F fly-ash, and wherein the hydratable cement further comprises a calcium-rich material additive.
14. The hydratable cement of claim 13 , wherein said calcium-rich material comprises an industrial byproduct selected from the group consisting of cement kiln dust, lime kiln dust, furnace slag, scrubber ash, and combinations thereof.
15. The hydratable cement of claim 1 , comprising 0.5 to 50 weight percent Class F fly-ash based on the total weight of the hydratable cement.
16. The hydratable cement of claim 1 , wherein the pozzolan powder consists essentially of Class N pozzolanic ash, and wherein the hydratable cement further comprises a calcium-rich material additive.
17. The hydratable cement of claim 16 , wherein said calcium-rich material comprises an industrial byproduct selected from the group consisting of cement kiln dust, lime kiln dust, furnace slag, scrubber ash, and combinations thereof.
18. The hydratable cement of claim 1 , comprising 0.5 to 50 weight percent Class N pozzolanic ash based on the total weight of the hydratable cement.
19. The hydratable cement of claim 1 , wherein the retarder comprises a borate compound.
20. The hydratable cement of claim 1 , comprising 0.1 to 3.0 weight percent of a borate retarder, based on the total weight of hydratable cement.
21. The hydratable cement of claim 1 , wherein the retarder comprises sulfates or organic compounds.
22. The hydratable cement of claim 1 , wherein the activator comprises potassium citrate or sodium citrate.
23. The hydratable cement of claim 1 , wherein the activator is comprised of 0.1 to 15 weight percent potassium citrate based on the total weight of the hydratable cement.
24. The hydratable cement of claim 1 , further comprising an additive selected from the group consisting of silica fume, calcium aluminate, magnesium oxide, lime, reactive clays such as meta-kaolin, wollastonite, air entraining agents (AEA), latex, fibers, water reducers and combinations thereof.
25. A hydratable cement comprising:
a pozzolan powder;
two or more activators, at least one of which has a pH between 6 and 9; and
a retarder,
wherein the hydratable cement has a calcium content expressed as the oxides of 15 wt % or more based on the total weight of the hydratable cement,
and wherein said activator having a pH of between about 6 and about 9 accounts for greater than 50% of the total weight of activators in said hydratable cement.
26. The hydratable cement of claim 25 , comprising alkali metal activators in an amount of less than 10% by weight of the total weight of activators in said hydratable cement.
27. The hydratable cement of claim 25 , comprising alkali metal carbonates in an amount of less than 10% by weight of the total weight of activators in said hydratable cement.
28. The hydratable cement of claim 25 , comprising alkali metal activators in an amount of less than 25% by weight of the total weight of activators in said hydratable cement.
29. The hydratable cement of claim 25 , comprising alkali metal activators in an amount of less than 30% by weight of the total weight of activators in said hydratable cement.
30. The hydratable cement of claim 25 , comprising citric acid in an amount of less than 10% by weight of the total weight of activators in said hydratable cement.
31. The hydratable cement of claim 25 , comprising citric acid in an amount of less than 30% by weight of the total weight of activators in said hydratable cement.
32. The hydratable cement of claim 25 , comprising citric acid in an amount of less than 25% by weight of the total weight of activators in said hydratable cement.
33. A hydratable cement according to claim 25 comprising Portland cement in an amount less than 20% by weight based on the total weight of the hydratable cement.
34. A hydratable cement according to claim 25 comprising Portland cement in an amount less than 15% by weight based on the total weight of the hydratable cement.
35. A hydratable cement according to claim 25 that is substantially free of Portland cement.
36. A hydratable cement according to claim 25 wherein the hydratable cement has a calcium content expressed as the oxides of 20 wt % or more based on the total weight of the hydratable cement.
37. The hydratable cement of claim 25 wherein the calcia to silica molar ratio is between about 1.2:1 and about 1.4:1.
38. The hydratable cement of claim 25 , wherein the pozzolan powder is selected from the group consisting of Class C fly-ash, Class F fly-ash, Class N pozzolanic ash and combinations thereof.
39. The hydratable cement of claim 25 , wherein the pozzolan powder consists essentially of Class C fly-ash and Class F fly-ash, wherein the Class C fly-ash is present in an amount of 50-80 weight percent, and the Class F fly-ash is present in an amount of 10-30 weight percent based on the total weight of the hydratable cement.
40. The hydratable cement of claim 25 , further comprising a calcium-rich material additive.
41. The hydratable cement of claim 40 , wherein said calcium-rich material comprises an industrial byproduct selected from the group consisting of cement kiln dust, lime kiln dust, furnace slag, scrubber ash, and combinations thereof.
42. The hydratable cement of claim 25 , wherein the pozzolan powder consists essentially of Class C fly-ash.
43. The hydratable cement of claim 25 , comprising 50 to 95 weight percent Class C fly-ash based on the total weight of the hydratable cement.
44. The hydratable cement of claim 25 , wherein the pozzolan powder consists essentially of Class F fly-ash, and wherein the hydratable cement further comprises a calcium-rich material additive.
45. The hydratable cement of claim 44 , wherein said calcium-rich material comprises an industrial byproduct selected from the group consisting of cement kiln dust, lime kiln dust, furnace slag, scrubber ash, and combinations thereof.
46. The hydratable cement of claim 25 , comprising 0.5 to 50 weight percent Class F fly-ash based on the total weight of the hydratable cement.
47. The hydratable cement of claim 25 , wherein the pozzolan powder consists essentially of Class N pozzolanic ash, and wherein the hydratable cement further comprises a calcium-rich material additive.
48. The hydratable cement of claim 47 , wherein said calcium-rich material comprises an industrial byproduct selected from the group consisting of cement kiln dust, lime kiln dust, furnace slag, scrubber ash, and combinations thereof.
49. The hydratable cement of claim 25 , comprising 0.5 to 50 weight percent Class N pozzolanic ash based on the total weight of the hydratable cement.
50. The hydratable cement of claim 25 , wherein the retarder comprises a borate compound.
51. The hydratable cement of claim 25 , comprising 0.1 to 3.0 weight percent of a borate retarder, based on the total weight of hydratable cement.
52. The hydratable cement of claim 25 , wherein the retarder comprises sulfates or organic compounds.
53. The hydratable cement of claim 25 , wherein the activator comprises potassium citrate or sodium citrate.
54. The hydratable cement of claim 25 , wherein the activator is comprised of 0.1 to 15 weight percent potassium citrate based on the total weight of the hydratable cement.
55. The hydratable cement of claim 25 , further comprising an additive selected from the group consisting of silica fume, calcium aluminate, magnesium oxide, lime, reactive clays such as meta-kaolin, wollastonite, air entraining agents (AEA), latex, fibers, water reducers and combinations thereof.
56. A cementitious composition comprising:
a hydratable cement comprising:
a pozzolan powder;
two or more activators, at least one of which has a pH between 6 and 9; and
a retarder,
wherein the hydratable cement has a calcium content expressed as the oxides of 15 wt % or more based on the total weight of the hydratable cement; and wherein said activator having a pH of between about 6 and about 9 accounts for greater than 50% of the total weight of activators in said hydratable cement;
and one or more aggregate fillers.
57. A cementitious composition comprising:
a hydratable cement comprising:
a pozzolan powder;
one or more pH neutral activators; and
a retarder,
wherein the hydratable cement has a calcium content expressed as the oxides of 15 wt % or more based on the total weight of the hydratable cement, and
wherein the pH neutral activators account for greater than 50% of the total weight of activators in said hydratable cement; and
wherein the hydratable cement has less than 20% by weight Portland cement based on the total weight of the hydratable cement;
and one or more aggregate fillers.