Crack-reducing admixture for cementitious compositions

Patent metadata

Field	Value
Publication number	US-9718732-B2
Application number	US-201414549942-A
Country	US
Kind code	B2
Filing date	Nov 21, 2014
Priority date	Nov 22, 2013
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

A cementitious composition including at least one cementitious material and at least one crack reducing admixture including: (i) from 0 to about 5 weight percent of at least one alcohol, based on the total weight of the admixture excluding water; and (ii) a compound having the chemical structure of formula (III):

wherein: v is an integer from 0 to 50 and w is an integer from 0 to 50, with the proviso that the sum of v and w is at least 1 but not greater than 50. Also, methods of making the cementitious composition, reducing or eliminating the formation of cracks in a cementitious composition as the cementitious composition cures, and limiting the size of cracks which form in a cementitious composition as the cementitious composition cures using an admixture for cementitious compositions as described herein.

First claim

What is claimed is:

1. A cementitious composition comprising at least one cementitious material and at least one crack reducing admixture comprising: (i) from 0 to about 5 weight percent of at least one alcohol, based on the total weight of the admixture excluding water; and (ii) a compound having the chemical structure of formula (III):

wherein:
v is an integer from 0 to 50; and
w is an integer from 0 to 50;
with the proviso that the sum of v and w is at least 1 but not greater than 50; and
wherein, during curing, the cementitious composition exhibits no cracks wider than about 175 μm.

2. The cementitious composition of claim 1 , wherein v is 2 and w is 2.

3. The cementitious composition of claim 1 , further comprising at least one air entraining admixture.

4. The cementitious composition of claim 3 , wherein the air entraining admixture comprises at least one synthetic air entrainer and/or at least one natural air entrainer.

5. The cementitious composition of claim 4 , wherein the air entraining admixture comprises at least one of fatty acid air entrainers, alkylbenzene sulfonate-based air entrainers, α-olefin sulfonate-based air entrainers, ethoxylated alcohol based air entrainers, tall oil, vinsol resin, or rosin.

6. The cementitious composition of claim 1 , further comprising aggregate and water.

7. The cementitious composition of claim 1 , wherein the crack reducing admixture is present in the cementitious composition in an amount of about 0.25 to about 4 gallons per cubic yard of the cementitious composition.

8. The cementitious composition of claim 1 , wherein, during curing, the cementitious composition exhibits no cracks wider than about 100 μm.

9. The cementitious composition of claim 1 , wherein the crack reducing admixture further comprises at least one acid in an amount effective to at least partially neutralize the admixture to reduce or eliminate the formation of precipitates in the admixture, optionally wherein the at least one acid comprises acetic acid.

10. A method of reducing or eliminating the formation of cracks in a cementitious composition as the cementitious composition cures, comprising adding to the uncured cementitious composition at least one crack reducing admixture comprising: (i) from 0 to about 5 weight percent of at least one alcohol, based on the total weight of the admixture excluding water; and (ii) a compound having the chemical structure of formula (III):

wherein:
v is an integer from 0 to 50; and
w is an integer from 0 to 50;
with the proviso that the sum of v and w is at least 1 but not greater than 50; and
wherein, during curing, the cementitious composition exhibits no cracks wider than about 175 μm.

11. The method of claim 10 , wherein v is 2 and w is 2.

12. The method claim 10 , further comprising adding at least one air entraining admixture to the cementitious composition.

13. The method of claim 12 , wherein the air entraining admixture comprises at least one synthetic air entrainer and/or at least one natural air entrainer.

14. The method of claim 13 , wherein the air entraining admixture comprises at least one of fatty acid air entrainers, alkylbenzene sulfonate-based air entrainers, α-olefin sulfonate-based air entrainers, ethoxylated alcohol based air entrainers, tall oil, vinsol resin, or rosin.

15. The method of claim 10 , further comprising adding aggregate and water to the cementitious composition.

16. The method of claim 10 , wherein the crack reducing admixture is added to the cementitious composition in an amount of about 0.25 to about 4 gallons per cubic yard of the cementitious composition.

17. The method of claim 10 , wherein the crack reducing admixture further comprises at least one acid in an amount effective to at least partially neutralize the admixture to reduce or eliminate the formation of precipitates in the admixture, optionally wherein the at least one acid comprises acetic acid.

18. A method of limiting the size of cracks which form in a cementitious composition as the cementitious composition cures to a width of less than or equal to about 175 μm, comprising adding to the uncured cementitious composition at least one crack reducing admixture comprising: (i) from 0 to about 5 weight percent of at least one alcohol, based on the total weight of the admixture excluding water; and (ii) a compound having the chemical structure of formula (III):

wherein:
v is an integer from 0 to 50; and
w is an integer from 0 to 50;
with the proviso that the sum of v and w is at least 1 but not greater than 50.

19. The method of claim 18 , wherein v is 2 and w is 2.

20. The method of claim 18 , wherein the crack reducing admixture is added to the cementitious composition in an amount of about 0.25 to about 4 gallons per cubic yard of the cementitious composition.

21. The cementitious composition of claim 1 , wherein v is an integer from 1 to 25 and w is an integer from 1 to 25.

22. The cementitious composition of claim 1 , wherein v is an integer from 2 to 10 and w is an integer from 2 to 10.

Assignees

• Construction Research & Technology Gmbh

Inventors

• Schaef Steve
• Attiogbe Emmanuel
• Kerobo Charles
• Muessig Stefan
• Vojtko Daniel

Classifications

• C04B18/08

  Flue dust {, i.e. fly ash} · CPC title

• Y02W30/92

  Cross-Sectional Technologies · mapped topic

• C04B2103/304

  Air-entrainers · CPC title

• C04B28/04

  Portland cements · CPC title

• C04B24/02 Primary

  Alcohols; Phenols; Ethers · CPC title