Fly ash cementitious compositions

Patent metadata

Field	Value
Publication number	US-10647612-B2
Application number	US-201615753534-A
Country	US
Kind code	B2
Filing date	Aug 26, 2016
Priority date	Aug 31, 2015
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

A composition comprising:
(a) fly ash cementitious binder; and (b) a chemical activator selected from sodium silicate, potassium silicate, sodium sulfate, sodium phosphate, calcium sulfate, potassium sulfate, potassium phosphate, CaO, Fe 2 O 3 , sodium chloride, calcium chloride, fine fraction of concrete waste from construction or demolition, cement kiln dust, or a combination thereof, wherein the fly ash is the only cementitious binder present in the composition and the CaO activator, if present, is present in an amount ≤10 weight percent, based on the total dry weight of the composition.

First claim

What is claimed is:

1. A composition comprising:
(a) fly ash cementitious binder;
(b) at least one of sodium silicate activator or potassium silicate activator;
(c) at least one of sodium sulfate activator, potassium sulfate activator, calcium sulfate activator, sodium phosphate activator, or potassium phosphate activator;
(d) at least one of CaO activator, Fe 2 O 3 activator, fine fraction of concrete waste from construction or demolition activator; and
(e) at least one of calcium chloride activator or sodium chloride activator,
wherein the fly ash is the only cementitious binder present in the composition and the CaO activator, if present, is present in an amount of ≤10 weight percent, based on the total dry weight of the composition.

2. The composition of claim 1 , wherein the fly ash comprises greater than 10 weight percent CaO, based on the total dry weight of the fly ash.

3. The composition of claim 1 , wherein the fly ash comprises less than 25 weight percent CaO, and has a weight ratio of Al 2 O 3 /(Al 2 O 3 +SiO 2 ) of at least 0.40, based on the total dry weight of the fly ash.

4. The composition of claim 1 , further comprising graphene oxide, multiwall carbon nanotubes, or a combination thereof.

5. The composition of claim 4 , wherein the graphene oxide or multiwall carbon nanotubes is present in an amount of 0.030 weight percent, based on the total dry weight of the composition.

6. The composition of claim 4 , wherein the graphene oxide or multiwall carbon nanotubes is present in an amount of 0.01 to 0.10 weight percent, based on the total dry weight of the composition.

7. The composition of claim 1 , wherein the composition includes 7 weight percent sodium silicate activator, 1 weight percent sodium sulfate activator, 5 weight percent CaO activator, and 1 weight percent calcium chloride activator, based on the weight of the fly ash.

8. The composition of claim 1 , wherein the composition includes 1 to 7 weight percent sodium silicate or potassium silicate activator, 1 to 3 weight percent sodium sulfate, potassium sulfate, calcium sulfate, sodium phosphate or potassium phosphate activator, 2 to 10 weight percent CaO or fine fraction of concrete waste from construction or demolition activator, based on the weight of the fly ash.

9. The composition of claim 1 , wherein the fly ash is a Class F or Class C fly ash.

10. The composition of claim 1 , wherein the composition includes sodium silicate, sodium sulfate, CaO, and calcium chloride.

11. The composition of claim 1 , further comprising graphene oxide.

12. The composition of claim 11 , wherein the graphene oxide is present in an amount of 0.030 weight percent, based on the total dry weight of the composition.

13. The composition of claim 10 , wherein the composition includes 1 to 7 weight percent sodium silicate activator, 1 to 3 weight percent sodium sulfate activator, 2 to 10 weight percent CaO activator, and 0.5 to 2 weight percent calcium chloride activator, based on the weight of the fly ash.

14. The composition of claim 10 , wherein the fly ash is a Class C fly ash.

15. The composition of claim 1 , wherein the composition further comprises at least one aggregate.

16. The composition of claim 1 , wherein the composition is in the form of a cementitious paste without any aggregate.

17. The composition of claim 1 , wherein the Fe 2 O 3 activator, if present, is present in an amount of ≤2 weight percent, based on the total dry weight of the composition.

18. A composition comprising:
(a) fly ash cementitious binder, wherein the fly ash comprises greater than 10 weight percent CaO, based on the total dry weight of the fly ash; and
(b) graphene oxide in an amount of 0.01 to 0.10 weight percent, based on the total dry weight of the composition,
wherein the fly ash is the only cementitious binder present in the composition.

19. The composition of claim 18 , wherein the fly ash comprises less than 25 weight percent CaO, and has a weight ratio of Al 2 O 3 /(Al 2 O 3 +SiO 2 ) of at least 0.40, based on the total dry weight of the fly ash.

20. The composition of claim 18 , wherein the composition further comprises a chemical activator selected from sodium silicate, potassium silicate, sodium sulfate, sodium phosphate, calcium sulfate, potassium sulfate, potassium phosphate, CaO, Fe 2 O 3 , sodium chloride, calcium chloride, fine fraction of concrete waste from construction or demolition, cement kiln dust, or a combination thereof.

21. The composition of claim 18 , wherein the composition further comprises a chemical activator selected from sodium silicate, sodium sulfate, CaO, calcium chloride, or a combination thereof.

22. The composition of claim 18 , wherein the graphene oxide is present in an amount of 0.030 weight percent, based on the total dry weight of the composition.

23. The composition of claim 18 , wherein the composition includes 7 weight percent sodium silicate activator, 1 weight percent sodium sulfate activator, 5 weight percent CaO activator, and 1 weight percent calcium chloride activator, based on the weight of the fly ash.

24. The composition of claim 18 , wherein the composition includes 1 to 7 weight percent sodium silicate activator, 1 to 3 weight percent sodium sulfate activator, 2 to 10 weight percent CaO activator, and 0.5 to 1 weight percent calcium chloride activator, based on the weight of the fly ash.

25. The composition of claim 18 , wherein the fly ash is a Class C fly ash.

26. The composition of claim 18 , wherein the composition further comprises at least one aggregate.

27. The composition of claim 18 , wherein the composition is in the form of a cementitious paste without any aggregate.

28. A method comprising;
(i) forming a mixture of (a) fly ash cementitious binder; (b) at least one of sodium silicate activator or potassium silicate activator; (c) at least one of sodium sulfate activator, potassium sulfate activator, calcium sulfate activator, sodium phosphate activator, or potassium phosphate activator; (d) at least one of CaO activator, Fe 2 O 3 activator, fine fraction of concrete waste from construction or demolition activator; and (e) at least one of calcium chloride or sodium chloride activator, wherein the fly ash is the only cementitious binder present in the composition and the CaO activator, if present, is present in an amount of ≤10 weight percent, based on the total dry weight of the composition; and
(ii) curing the mixture at ambient temperature and ambient pressure.

29. The method of claim 28 , wherein the curing comprises adding water to the mixture (i).

30. A method comprising:
(i) forming a mixture of (a) fly ash cementitious binder, wherein the fly ash comprises greater than 10 weight percent CaO, based on the total dry weight of the fly ash and (b) graphene oxide in an amount of 0.01 to 0.10 weight percent, based on the total dry weight of the composition, wherein the fly ash is the only cementitious binder present in the composition; and
(ii) curing the mixture at ambient temperature and ambient pressure.

31. The method of claim 30 , wherein the curing comprises adding water to the mixture (i).

32. A composition comprising:
(a) a Class C fly ash cementitious binder;
(b) a chemical activator consisting of sodium silicate, potassium silicate, sodium sulfate

Assignees

• Shi Xianming
• Xu Gang
• Univ Washington State

Inventors

• Shi Xianming
• Xu Gang

Classifications

• C04B22/16

  containing phosphorus in the anion, e.g. phosphates · CPC title

• C04B22/143

  Calcium-sulfate · CPC title

• C04B22/147

  Alkali-metal sulfates; Ammonium sulfate · CPC title

• C04B18/162

  Cement kiln dust; Lime kiln dust · CPC title

• C04B22/064

  of the alkaline-earth metals · CPC title