Gypsum-cement system for construction materials

• US 6,241,815 B1
• Filed: 08/10/1999
• Issued: 06/05/2001
• Est. Priority Date: 08/10/1999
• Status: Expired due to Term

• Current Assignee: United States Gypsum Company (GEBR Knauf Verwaltungsgesellschaft KG)
• Original Assignee: United States Gypsum Company (GEBR Knauf Verwaltungsgesellschaft KG)
• Inventors: Bonen, David
• Primary Examiner(s): GREEN, ANTHONY J
• Application Number:
  US09/371,351
• Time in Patent Office: 665 Days
• Field of Search: 106/718, 106/719, 106/720, 106/721, 106/722, 106/724, 106/725, 106/726, 106/727, 106/728, 106/732, 106/735, 106/709, 106/715, 156/39, 428/703
• US Class Current: 106/735
• CPC Class Codes: C04B 14/106 Kaolin
• CPC Class Codes: C04B 14/108 Shale, slate colliery shale C04B18/125
• CPC Class Codes: C04B 18/025 Grog
• CPC Class Codes: C04B 18/08 Flue dust , i.e. fly ash
• CPC Class Codes: C04B 18/141 Slags
• CPC Class Codes: C04B 18/146 Silica fume
• CPC Class Codes: C04B 2103/10 Accelerators; Activators
• CPC Class Codes: C04B 2103/20 Retarders
• CPC Class Codes: C04B 2103/32 Superplasticisers
• CPC Class Codes: C04B 22/064 of the alkaline-earth metals
• CPC Class Codes: C04B 22/124 Chlorides of ammonium or of the alkali or alkaline earth metals, e.g. calcium chloride
• CPC Class Codes: C04B 22/143 Calcium-sulfate
• CPC Class Codes: C04B 24/02 Alcohols; Phenols; Ethers
• CPC Class Codes: C04B 24/06 containing hydroxy groups
• CPC Class Codes: C04B 24/123 Amino-carboxylic acids
• CPC Class Codes: C04B 24/20 Sulfonated aromatic compounds
• CPC Class Codes: C04B 28/145 Calcium sulfate hemi-hydrate with a specific crystal form
• CPC Class Codes: C04B 38/10 by using foaming agents C04B38/02 takes precedenceor by using mechanical means, e.g. adding preformed foam
• CPC Class Codes: C04B 7/02 Portland cement
• CPC Class Codes: E04C 2/06 reinforced
• CPC Class Codes: Y02W 30/91 : Use of waste materials as fillers for mortars or concrete

Abstract

A composition for use in construction materials, which may be substituted for high performance concrete, patching materials, joint compounds, and the like, such as backer boards or panels, which includes a settable calcium sulfate, preferably a hemihydrate, Portland cement, a finely divided pozzolanic material, lime, and an aggregate, optionally including other additives. The volume ratio of the aggregate to the combined calcium sulfate, Portland cement, pozzolanic material, and lime (a cementitious binder) is equal to or greater than 2/1. Panels made from this composition are useful, particularly when exposed to water since they have good dimensional stability.

Claims

1. A composition for use in construction materials comprising:

(a) a cementitious material comprising;

(1) about 25-80 wt % of a settable calcium sulfate;

(2) about 10-60 wt % Portland cement;

(3) up to about 40 wt % of a finely divided pozzolanic material;

(4) less than 5 wt % of Ca(OH)₂; and

(b) an aggregate, the volume of said aggregate to the cementitious material of (a) being at least about 2/1.

2. A composition of claim 1, further comprising at least one of the group consisting of:

(c) up to about 2 wt % of an accelerator for Portland cement based on the amount of (a)(2), (a)(3), and (a)(4);

(d) up to about 1.8 wt % of a superplasticizer based on the cementitious material of (a);

(e) about 0.3-2.0 wt % of an accelerator for gypsum based on the amount of (a)(1);

(f) up to about 0.08 wt % of a retarder based on the cementitious material of (a);

(g) about 2-7 wt % of a glycol relative to the amount of water to be mixed with said cementitious material of (a); and

(h) up to about 75% by volume of a stable foam.

3. A composition of claim 2, wherein said accelerator for Portland cement is calcium chloride.

4. A composition of claim 2, wherein said superplasticizer is the sodium salt of polynaphthalene sulfonate.

5. A composition of claim 2, wherein said accelerator for gypsum is calcium sulfate dihydrate.

6. A composition of claim 2, wherein said retarder is selected from the group consisting of DTPA (diethylenetriaminepentacetic acid), tartaric acid, and alkali salts of tartaric acid.

7. A composition of claim 1, wherein said pozzolanic material is about 6-35 wt % of said cementitious material.

8. A composition of claim 1, wherein said Portland cement is selected from the group consisting of ASTM Type I, Type III, Type IP, Type IS, Type V, and Type C.

9. A composition of claim 1, wherein said settable calcium sulfate is calcium sulfate beta hemihydrate.

10. A composition of claim 1, wherein said settable calcium sulfate is calcium sulfate alpha hemihydrate.

11. A composition of claim 1, wherein said settable calcium sulfate is a mixture of calcium sulfate alpha and beta hemihydrates.

12. A composition of claim 1, wherein said pozzolanic material is silica fume, metakaolin, ground granulated blast furnace slag, or pulverized fly ash.

13. A composition of claim 12, wherein said pozzolanic material is silica fume.

14. A composition of claim 12, wherein said pozzolanic material is metakaolin.

15. A composition of claim 12, wherein said pozzolanic material is ground granulated blast furnace slag.

16. A composition of claim 12, wherein said pozzolanic material is pulverized fly ash.

17. A composition of claim 1, wherein said aggregate is a sintered shale.

18. A composition of claim 1, wherein said aggregate includes no more than about 5 wt % of particles smaller than 20 μ

m.

19. A panel comprising:

(a) a composition of claim 1 formed into a panel; and

(b) a scrim facing on each surface of said panel.

20. A panel comprising:

(a) a composition of claim 2 formed into a panel; and

(b) a scrim facing on each surface of said panel.

21. A backer panel comprising:

(a) a cementitious binder resulting from the curing of an aqueous mixture, said mixture comprising, on a dry basis;

(1) about 50-80 wt % of beta calcium sulfate hemihydrate;

(2) about 10-40 wt % of Type III Portland cement;

(3) about 6-35 wt % of a finely divided pozzolanic material selected from the group consisting of silica fume, metakaolin, ground granulated blast furnace slag and pulverized fly ash;

(4) greater than zero, but less than 5 wt % Ca(OH)₂;

(b) an aggregate, the volume ratio of said aggregate to the cementitious binder of (a) being at least 2/1; and

(c) at least one additive selected from the group consisting of;

(1) up to about 2 wt % of an accelerator for Portland cement, based on the amount of (a)(2), (a)(3), and (a)(4);

(2) up to about 1.8 wt % of a superplasticizer based on the cementitious binder of (a);

(3) about 0.3-2.0 wt % of an accelerator for gypsum based on the amount of (a)(1);

(4) up to about 0.08 wt % of a retarder based on the cementitious binder of (a);

(5) about 2-7 wt % of a glycol relative to the amount of water which has been mixed with the cementitious binder of (a); and

(6) up to about 75% by volume of a stable foam.

22. A composition for use in construction materials comprising

(a) a cementitious material comprising:

(1) about 25-80 wt % of a settable calcium sulfate;

(2) about 1-60 wt % Portland cement;

(3) up to about 40 wt % metakaolin; and

(4) less than 5 wt % Ca(OH)₂;

(b) an aggregate, the volume ratio of said aggregate to the cementitious material of (a) being at least about 2/1.

23. A cementitious material of claim 22, wherein the settable calcium sulfate is selected from the group consisting of alpha hemihydrate, beta hemihydrate, and mixtures thereof.

24. A cementitious material of claim 22, wherein the Portland cement is selected from the group consisting of ASTM Type I, Type III, Type IP, Type IS, Type V, and Type C.