Fly ash cementitious compositions

Patent metadata

Field	Value
Publication number	US-2018257989-A1
Application number	US-201615753534-A
Country	US
Kind code	A1
Filing date	Aug 26, 2016
Priority date	Aug 31, 2015
Publication date	Sep 13, 2018
Grant date	—

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

1 . 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 of ≤10 weight percent, based on the total dry weight of the composition.

2 . The composition of claim 1 , wherein the composition includes (i) at least one of sodium silicate or potassium silicate, (ii) at least one of sodium sulfate, potassium sulfate, calcium sulfate, sodium phosphate, or potassium phosphate, (iii) at least one of CaO, Fe 2 O 3 , fine fraction of concrete waste from construction or demolition, and (iv) at least one of calcium chloride or sodium chloride.

3 . 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.

4 . 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.

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

6 . The composition of claim 5 , 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.

7 . The composition of claim 5 , 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.

8 . The composition of claim 2 , 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.

9 . The composition of claim 2 , 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, and 0 to 1 weight percent calcium chloride or sodium chloride activator, based on the weight of the fly ash.

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

11 . The composition of claim 1 , wherein the chemical activator is selected from sodium silicate, sodium sulfate, CaO, calcium chloride, or a combination thereof,

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

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

14 . The composition of claim 13 , wherein the graphene oxide is present in an amount of 0.030 weight percent, based on the total dry weight of the composition.

15 . The composition of claim 12 , 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.

16 . The composition of claim 11 , wherein the fly ash is a Class C fly ash.

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

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

19 . 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.

20 . A composition comprising:
(a) fly ash cementitious binder; and (b) graphene oxide, wherein the fly ash is the only cementitious binder present in the composition.

21 . The composition of claim 20 , wherein the fly ash comprises greater than 10 weight percent CaO, based on the total dry weight of the fly ash.

22 . The composition of claim 20 , 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.

23 . The composition of claim 20 , 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.

24 . The composition of claim 20 , wherein the composition further comprises a chemical activator selected from sodium silicate, sodium sulfate, CaO, calcium chloride, or a combination thereof.

25 . The composition of claim 20 , wherein the graphene oxide is present in an amount of 0.030 weight percent, based on the total dry weight of the composition.

26 . The composition of claim 20 , wherein the graphene oxide is present in an amount of 0.01 to 0.10 weight percent, based on the total dry weight of the composition.

27 . The composition of claim 20 , 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.

28 . The composition of claim 20 , 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.

29 . The composition of claim 20 , wherein the fly ash is a Class F fly ash or Class C fly ash.

30 . The composition of claim 20 , wherein the composition further comprises at least one aggregate.

31 . The composition of claim 20 , wherein the composition is in the form of a cementitious paste without any aggregate.

32 . A method comprising;
(i) forming a mixture of (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 of ≤10 weight percent, based on the total dry weight of the composition; and (ii) curing the mixture at ambient temperature and ambient pressure.

33 . The method of claim 32 , wherein the curing comprises adding water to the mixture (i).

34 . A method comprising:
(i) forming a mixture of (a) fly ash cementitious binder and (b) grap

Assignees

• Univ Washington State

Inventors

• Shi Xianming
• Xu Gang

Classifications

• C04B22/124

  Chlorides of ammonium or of the alkali or alkaline earth metals, e.g. calcium chloride · CPC title

• C04B22/147

  Alkali-metal sulfates; Ammonium sulfate · CPC title

• C04B28/021 Primary

  Ash cements, e.g. fly ash cements (fly ash as filler C04B18/08); Cements based on incineration residues, e.g. alkali-activated slags from waste incineration (alkali-activated combustion residues as such C04B7/243; mixtures of the lime-pozzuolane type C04B28/18); Kiln dust cements · CPC title

• C04B22/143

  Calcium-sulfate · CPC title

• C04B18/162

  Cement kiln dust; Lime kiln dust · CPC title