Cement admixture

• US 5,571,319 A
• Filed: 09/18/1995
• Issued: 11/05/1996
• Est. Priority Date: 09/18/1995
• Status: Expired due to Term

• Current Assignee: GCP Applied Technologies Inc. (Compagnie De Saint-Gobain)
• Original Assignee: W R Grace & Company - CONN (WR Grace & Company)
• Inventors: Berke, Neal S., Dallaire, Michael P.
• Primary Examiner(s): Group, Karl
• Assistant Examiner(s): MARCHESCHI, MICHAEL A
• Application Number:
  US08/529,388
• Time in Patent Office: 414 Days
• Field of Search: 106/724, 106/737, 106/802, 106/738, 106/817, 106/819, 106/823
• US Class Current: 106/802
• CPC Class Codes: C04B 18/101 Burned rice husks or other burned vegetable material
• CPC Class Codes: C04B 18/146 Silica fume
• CPC Class Codes: C04B 2103/61 Corrosion inhibitors
• CPC Class Codes: C04B 22/085 containing nitrogen in the anion, e.g. nitrites
• CPC Class Codes: C04B 24/02 Alcohols; Phenols; Ethers
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: C04B 40/0039 Premixtures of ingredients
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete

Abstract

A fluid, stable aqueous dispersion of silica fume and alkali or alkaline earth metal nitrite salt. The dispersion contains a water soluble alkylene glycol.

Claims

1. A cement admixture comprising a uniform aqueous dispersion of

a) from about 10 to 50 weight percent of silica fume;

b) at least one alkali metal or alkaline earth metal nitrite in a weight ratio of nitrite salt to silica fume of from about 1;

2 to 1;

10; and

c) at least a stabilizing amount of at least one glycol selected from (i) C₃ -C₁₂ alkylene glycol or (ii) a water soluble condensed alkylene glycol represented by the formula HO(AO)_x H wherein A is a C₂ -C₄ alkylene or mixture thereof, O represents oxygen and x is an integer of from 1 to 20;

or mixtures thereof.

2. The cement admixture of claim 1 wherein the silica fume is a by-product of silicon and/or ferro silicon alloy production and the glycol is present in from about 30 to 70 weight percent based on the silica fume present in the admixture.

3. The cement admixture of claim 1 wherein the silica fume is a product of pyrolysis of rice hull or calcining of alumina-silica clay and the glycol is present in from about 30 to 70 weight percent based on the silica fume present in the admixture.

4. The cement admixture of claim 1, wherein the C₃ -C₁₂ alkylene glycol is represented by the formula HOBOH wherein B is a C₅ -C₈ alkylene.

5. The cement admixture of claim 2, wherein the C₃ -C₁₂ alkylene glycol is represented by the formula HOBOH wherein B is a C₅ -C₈ alkylene.

6. The cement admixture of claim 3, wherein the C₃ -C₁₂ alkylene glycol is represented by the formula HOBOH wherein B is a C₅ -C₈ alkylene.

7. The admixture of claim 1 wherein said C₃ -C₁₂ alkylene glycol is represented by the formula ##STR2## wherein each R represents a hydrogen atom or C₁ -C₂ alkyl;

each R'"'"' represents C₁ -C₂ alkyl; and

n represents 1 or 2.

8. The admixture of claim 2 wherein said C₃ -C₁₂ alkylene glycol is represented by the formula ##STR3## wherein each R represents a hydrogen atom or C₁ -C₂ alkyl;

each R'"'"' represents C₁ -C₂ alkyl; and

n represents 1 or 2.

9. The admixture of claim 3 wherein said C₃ -C₁₂ alkylene glycol is represented by the formula ##STR4## wherein each R represents a hydrogen atom or C₁ -C₂ alkyl;

each R'"'"' represents C₁ -C₂ alkyl; and

n represents 1 or 2.

10. The admixture of claim 7 wherein said C₃ -C₁₂ alkylene glycol is 2-methyl-2,4-pentanediol.

11. The admixture of claim 1 wherein the alkali metal nitrite is calcium nitrite.

12. The admixture of claim 4 wherein the alkali metal nitrite is calcium nitrite.

13. The admixture of claim 7 wherein the alkali metal nitrite is calcium nitrite.

14. The admixture of claim 1 wherein the condensed alkylene glycol is represented by the formula HO(AO)_x H wherein A is a C₂ -C₃ alkylene or mixture thereof, O is oxygen, and x is a value of 1 to 10.

15. The admixture of claim 2 wherein the condensed alkylene glycol is represented by the formula HO(AO)_x H wherein A is a C₂ -C₃ alkylene or mixture thereof, O is oxygen, and x is a value of 1 to 10.

16. The admixture of claim 3 wherein the condensed alkylene glycol is represented by the formula HO(AO)_x H wherein A is a C₂ -C₃ alkylene or mixture thereof, O is oxygen, and x is a value of 1 to 10.

17. The admixture of claim 14 wherein the alkali metal nitrite is calcium nitrite.

18. The admixture of claim 15 wherein the alkali metal nitrite is calcium nitrite.

19. The admixture of claim 16 wherein the alkali metal nitrite is calcium nitrite.

20. A method of forming a concrete structural formation comprising:

(i) forming a cement composition composed of a hydraulic cement, fine aggregate, coarse aggregate and water with a water to cement weight ratio of from 0.25;

1 to 0.7;

1;

(ii) adding to said cement composition from 2 to 25 weight percent, based on the hydraulic cement content of the cement composition, of a cement admixture comprising a uniform aqueous dispersion of

a) from about 10 to 50 weight percent of silica fume;

b) at least one alkali metal or alkaline earth metal nitrite in a weight ratio of nitrite salt to silica fume of from about 1;

2 to 1;

10; and

c) at least a stabilizing amount of at least one glycol selected from (i) C₃ -C₁₂ alkylene glycol or (ii) a water soluble condensed alkylene glycol represented by the formula HO(AO)_x H wherein A is a C₂ -C₄ alkylene or mixture thereof, O represents oxygen and x is an integer of from 1 to 20;

or mixtures thereof.

21. The method of claim 20 wherein the silica fume is a by-product of silicon and/or ferro silicon alloy production and the glycol is present in from about 30 to 70 weight percent based on the silica fume present in the admixture.

22. The method of claim 20 wherein the silica fume is a product of pyrolysis of rice hull or calcining of alumina-silica clay and the glycol is present in from about 30 to 70 weight percent based on the silica fume present in the admixture.

23. The method of claim 21 wherein the C₃ -C₁₂ alkylene glycol is represented by the formula HOBOH wherein B is a C₅ -C₈ alkylene.

24. The method of claim 22 wherein the C₃ -C₁₂ alkylene glycol is represented by the formula HOBOH wherein B is a C₅ -C₈ alkylene.

25. The method of claim 21 wherein the condensed alkylene glycol is represented by the formula HO(AO)_x H wherein A is a C₂ -C₃ alkylene or mixture thereof, O is oxygen, and x is a value of 1 to 10.

26. The method of claim 22 wherein the condensed alkylene glycol is represented by the formula HO(AO)_x H wherein A is a C₂ -C₃ alkylene or mixture thereof, O is oxygen, and x is a value of 1 to 10.

27. The method of claim 24 wherein the metal nitrite is calcium nitrite.

28. The method of claim 26 wherein the metal nitrite is calcium nitrite.