Cement composition
AssigneeW. R. Grace & Co.-Conn.
InventorsEdward T. Shawl, Haven S. Kesling, Jr.
Life of this patent
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Abstract
A cement admixture comprised of a mixture of certain alkyl ether oxyalkylene adducts with certain oxyalkylene glycols to provide cement compositions of mortar and concrete which inhibit drying shrinkage while permitting substantial air entrainment and enhanced compressive strength.
Claims12
A cement admixture capable of inhibiting enhanced drying shrinkage while substantially maintaining a desired air void content of a treated cement composition caused by the presence of an air-entraining agent, comprising
- (a) at least one alkyl ether oxyalkylene adduct represented by the formula
- RO(AO).sub.n H
- wherein A is a C.sub.2 -C.sub.4 alkylene radical, O is an oxygen atom, R is a tertiary alkyl group and n is an integer from 1 to 3;
- and
- (b) an oxyalkylene glycol represented by the formula
- HO(AO).sub.m H
- wherein A is a C.sub.2 -C.sub.4 alkylene radical, O is an oxygen atom, and m is an integer of 1 to 3, said oxyalkylene glycol being present in an amount which is sufficient to provide shrinkage reduction in combination with said component (a) adduct and which is sufficient to offset the air-detraining effect of said component (a) adduct and thereby permit a desired degree of air-entrainment to be obtained in the set composition by the presence of an air-entraining agent l said oxyalkylene glycol optionally containing a mixing material selected from the group consisting of fly ash, an AE agent, an AE dehydrating agent, and an inorganic swelling agent;
- and
- said oxyalkylene adduct and said oxyalkylene glycol being used in a weight ratio of 1:2 to 10:1.
A method of inhibiting drying shrinkage of a cast hydraulic cement structure while maintaining high air content therein comprising
- introducing into an unset cement composition from 0.1 to 5 weight percent of the hydraulic cement, and admixture comprising:
- (a) at least one alkyl ether oxyalkylene adduct represented by the formula
- RO(AO).sub.n H
- wherein A is a C.sub.3 -C.sub.4 alkylene radical, O is an oxygen atom, R is C.sub.3 -C.sub.5 alkyl group and n is an integer from 1 to 3;
- and
- (b) an oxyalkylene glycol represented by the formula
- HO(AO).sub.m H
- wherein A is a C.sub.2 -C.sub.4 alkylene radical, O is an oxygen atom, and m is an integer of 1 to 3, said oxyalkylene glycol being present in an amount which is sufficient to provide shrinkage reduction in combination with said component (a) adduct and which is sufficient to offset the air-detraining effect of said component (a) adduct and thereby permit a desired degree of air-entrainment to be obtained in the set composition by the presence of an air-entraining agent, said alkyl ether oxyalkylene adduct and said oxyalkylene glycol being used in a weight ratio of 1:2 to 1 0:
- 1;
- casting the cement composition comprising said admixture into a desired shape;
- and
- permitting said composition to cure.
The composition of claim wherein said oxyalkylene glycol has an average molecular weight of 200 to 600.
A cement admixture, comprising
- (a) at least one alkyl ether oxyalkylene adduct represented by the formula RO(AO).sub.n H wherein A is a C.sub.2 -C.sub.4 alkylene radical, O is an oxygen atom, R is a tertiary alkyl group and n is an integer from 1 to 3;
- (b) an oxyalkylene glycol represented by the formula HO(AO).sub.m H wherein A is a C.sub.2 -C.sub.4 alkylene radical, O is an oxygen atom, and m is an integer of 1 to 3;
- said oxyalkylene adduct and said oxyalkylene glycol being used in a weight ratio of 1:2 to 10:1;
- and (c) an air entraining agent that is different from said alkylene adduct and said oxyalkylene glycol.
Dependencies are inferred from the claim text.