Aluminate-enhanced type i portland cements with short setting times and cement boards produced therefrom

Patent metadata

Field	Value
Publication number	US-2020331802-A1
Application number	US-202016801083-A
Country	US
Kind code	A1
Filing date	Feb 25, 2020
Priority date	Apr 17, 2019
Publication date	Oct 22, 2020
Grant date	—

Abstract

Aqueous cementitious slurries including predominantly Type I Portland cement containing an aluminate additive. The aluminate additive is an aluminate salt other than calcium aluminate or calcium sulfoaluminate, preferably sodium aluminate. Cementitious reactive powders of the slurry include the Type I Portland cement and 0.1-10 wt. % of the aluminate additive as an accelerator. The slurries may have a set time of about 10 minutes or less. Due to the short set time, the cementitious reactive powders may facilitate cement board fabrication by continuous manufacturing processes. Methods for making cement boards may include disposing the aqueous cementitious slurry including the cementitious reactive powders in a continuous layer, preferably upon a porous support, and setting the aqueous cementitious slurry with a set time of about 10 minutes or less.

First claim

What is claimed is the following:

1 . A cement board comprising:
a continuous layer formed from setting of an aqueous cementitious slurry, the aqueous cementitious slurry comprising:
water; and
a cementitious reactive powder comprising:
60 to 100 wt. % Type I Portland cement, and

a set accelerator comprising an aluminate additive other than calcium aluminate or calcium sulphoaluminate, the set accelerator in an amount equal to 0.1-10 wt. % of the cementitious reactive powder.

2 . The cement board of claim 1 , wherein the aluminate additive comprises an aluminate salt selected from the group consisting of ammonium aluminate, sodium aluminate, potassium aluminate, magnesium aluminate, and any combination thereof.

3 . The cement board of claim 1 , wherein the aluminate additive is formed from an aluminate precursor within the aqueous cementitious slurry, the aluminate precursor being selected from the group consisting of aluminum sulfate, aluminum hydroxide, boehmite (AlO(OH)), and any combination thereof.

4 . The cement board of claim 1 , wherein the cementitious reactive powder comprises 80 to 100 wt. % Type I Portland cement.

5 . The cement board of claim 1 , wherein the cementitious reactive powder has at most 10 wt. % total Type II Portland cement and Type III Portland cement.

6 . The cement board of claim 1 , wherein the cementitious reactive powder has an absence of Type III Portland cement.

7 . The cement board of claim 1 , wherein the cementitious reactive powder has an absence of Type II Portland cement and an absence of Type III cement.

8 . The cement board of claim 1 , wherein the cementitious reactive powder is substantially free of calcium sulphoaluminate, substantially free of calcium aluminate, has an absence of barium borate, has an absence of lithium carbonate and an absence of aluminum sulfate, and has an absence of polyvinyl alcohol, an absence of polyvinyl alcohol polyvinyl acetate, has an absence of a polyhydroxy aromatic compound, has an absence of polycarboxylic acid-containing compound, has an absence of a salt of polycarboxylic acid-containing compound, has an absence of ascorbic acid, has an absence of salt of ascorbic acid, has an absence of lithium carbonate, and has an absence of aluminum sulfate.

9 . The cement board of claim 1 , wherein the cementitious reactive powder comprises 0 to 30 wt. % pozzolanic material.

10 . The cement board of claim 1 , wherein the pozzolanic material comprises Class C fly ash, Class F fly ash, or any combination thereof.

11 . The cement board of claim 1 , wherein the aqueous cementitious slurry comprises an additive selected from sand, a mineral aggregate, a non-mineral aggregate, a clay, mica, calcium carbonate, and any combination thereof.

12 . The cement board of claim 1 , wherein the cementitious reactive powder comprises up to 5 wt. % of an alkaline additive.

13 . The cement board of claim 11 , wherein the alkaline additive is selected from the group consisting of sodium hydroxide, calcium oxide, sodium monophosphate, sodium polyphosphates, and sodium trimetaphosphate (STMP).

14 . The cement board of claim 1 , wherein the aqueous cementitious slurry comprises an additive selected from the group consisting of an accelerator, a retarder, a plasticizer, a superplasticizer, a foaming agent, gypsum, triethanolamine, a polyacrylamide, potassium dichromate, and any combination thereof.

15 . The cement board of claim 1 , wherein Type I Portland cement is the only cement present in the cementitious reactive powder.

16 . A method for processing a cementitious composition, comprising:
combining water and a cementitious reactive powder to form an aqueous cementitious slurry; wherein the cementitious reactive powder comprises:
60 to 100 wt. % Type I Portland cement, and
a set accelerator comprising an aluminate additive other than calcium aluminate or calcium sulphoaluminate, the set accelerator provided in an amount equal to 0.1-10 wt. % of the cementitious reactive powder.

17 . The method of claim 16 , wherein the aluminate additive comprises an aluminate salt selected from the group consisting of ammonium aluminate, sodium aluminate, potassium aluminate, magnesium aluminate, and any combination thereof.

18 . The method of claim 16 , wherein the aluminate additive is formed from an aluminate precursor within the aqueous cementitious slurry, the aluminate precursor being selected from the group consisting of aluminum sulfate, aluminum hydroxide, boehmite (AlO(OH)), and any combination thereof.

19 . The method of claim 16 , wherein the cementitious reactive comprises at most 10 wt. % Type III Portland cement, wherein the cementitious composition is free of Type III Portland cement, free of calcium aluminate, and free of calcium sulphoaluminate.

20 . The method of claim 16 , wherein the cementitious reactive powder comprises up to 5 wt. % of an alkaline additive.

Assignees

• United States Gypsum Co

Inventors

• Li Qinghua
• Peng Yanfei

Classifications

• C04B28/04 Primary

  Portland cements · CPC title

• C04B14/20

  Mica; Vermiculite {(mechanical splitting B28D)} · CPC title

• C04B7/428

  Organic materials · CPC title

• C04B28/14

  containing calcium sulfate cements {(gypsum-paper plates E04C)} · CPC title

• C04B14/28

  of calcium · CPC title