Aluminate-enhanced type I Portland cements with short setting times and cement boards produced therefrom

Patent metadata

Field	Value
Publication number	US-11180412-B2
Application number	US-202016801083-A
Country	US
Kind code	B2
Filing date	Feb 25, 2020
Priority date	Apr 17, 2019
Publication date	Nov 23, 2021
Grant date	Nov 23, 2021

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:
only one continuous layer formed from setting of an aqueous cementitious slurry,
wherein the aqueous cementitious slurry comprises:
water; and
a cementitious reactive powder comprising:
80 to 100 wt. % Type I Portland cement,
wherein the cementitious reactive powder is substantially free of calcium sulfoaluminate cement and is substantially free of calcium aluminate cement,
optionally up to 20 wt. % pozzolanic material, 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, wherein the aluminate additive comprises an aluminate salt selected from ammonium aluminate, sodium aluminate, potassium aluminate, magnesium aluminate, and any combination thereof, or an aluminate precursor selected from aluminum hydroxide, boehmite (AlO(OH)), and any combination thereof; and
wherein the slurry has an absence of non-mineral aggregate,
wherein all filler of the slurry consists of mineral filler,
wherein the slurry has an absence of hollow plastic spheres and wherein the slurry has an absence of expanded plastic beads;
wherein the cementitious reactive powder has an absence of aluminum sulfate.

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 hydroxide, boehmite (AlO(OH)), and any combination thereof.

4. 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.

5. The cement board of claim 1 , wherein the cement board consists of the continuous laver as a core layer, and optionally at least one facing sheet of fiberglass scrim on the continuous core layer.

6. 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,
wherein the aluminate additive is sodium aluminate in an amount that is effective to realize a set time for the aqueous cementitious slurry of 10 minutes or less,
wherein the mineral filler and mineral aggregate, if present, consists of vermiculite and/or coated perlite with less than 0.10 open porosity.

7. The cement board of claim 1 , wherein the cementitious reactive powder has an absence of barium borate, 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.

8. The cement board of claim 1 , wherein the cementitious reactive powder comprises 0 to 30 wt. % pozzolanic material, wherein at least 80 wt. % of the aggregate and filler is coated perlite.

9. The cement board of claim 8 , wherein the pozzolanic material comprises Class C fly ash, Class F fly ash, or any combination thereof.

10. 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.

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

12. 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).

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

14. The cement board of claim 1 , wherein Type I Portland cement is the only cement present in the cementitious reactive powder, wherein the slurry has an absence of calcium carbonate.

15. A method for processing a cementitious composition to make a cement board according to claim 1 , comprising:
combining water and a cementitious reactive powder to form an aqueous cementitious slurry;
wherein the cementitious reactive powder comprises:
80 to 100 wt. % Type I Portland cement,
wherein the cementitious reactive powder is substantially free of calcium sulfoaluminate cement and is substantially free of calcium aluminate cement,
optionally up to 20 wt. % pozzolanic material, 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,
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, or an aluminate precursor selected from the group consisting of aluminum hydroxide, boehmite (AlO(OH)), and any combination thereof; and
wherein the slurry has an absence of non-mineral aggregate,
wherein all filler of the slurry consists of mineral filler,
wherein the slurry has an absence of hollow plastic spheres and wherein the slurry has an absence of expanded plastic beads;
wherein the cementitious reactive powder has an absence of aluminum sulfate.

16. The method of claim 15 , 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.

17. The method of claim 15 , 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 hydroxide, boehmite (AlO(OH)), and any combination thereof.

18. The method of claim 15 , wherein the cementitious composition is free of Type III Portland cement, free of Type II Portland cement, free of calcium aluminate, and free of calcium sulphoaluminate, wherein the aluminate additive is sodium aluminate in an amount that is effective to realize a set time for the aqueous cementitious slurry of 10 minutes or less.

19. The method of claim 15 , wherein the cementitious reactive powder comprises up to 5 wt. % of an alkaline additive.

20. A cement board consisting of:
only one continuous layer formed from setting of an aqueous cementitious slurry,
optionally the continuous layer is sandwiched between two porous supports of fiberglass scrim;
wherein the aqueous cementitious slurry consists of:
water; and
a cementitious reactive powder comprising:
80 to 100 wt. % Type I Portland cement,
wherein the cementitious reactive powder is substantially free of calcium sulfoaluminate cement and is substantially free of calcium aluminate cement,
optionally up to 20 wt. % pozzolanic material, and

Assignees

• United States Gypsum Co

Inventors

• Li Qinghua
• Peng Yanfei

Classifications

• C04B2111/00612

  as one or more layers of a layered structure · CPC title

• C04B14/20

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

• C04B14/06

  Quartz; Sand · CPC title

• C04B7/424

  Oxides, Hydroxides · CPC title

• C04B2103/12

  Set accelerators · CPC title