Polymeric composition for cement based substructures

1. A composition composed of an aqueous mixture of at least one first copolymer comprising mer units derived from vinylidene halide and mer units derived from C 1 -C 2 alkyl acrylate, said mer units derived from C 1 -C 2 alkyl acrylate being present in from 5 to 40 weight percent of the first copolymer; and at least one second copolymer comprising mer units derived from vinylidene halide and mer units derived from C 4 -C 5 alkyl acrylate, said mer units derived from C 4 -C 5 alkyl acrylate being present in from 3 to 40 weight percent of the second copolymer, wherein said first copolymer and said second copolymer are in a weight ratio of 90:10 to 10:90; the first and second copolymers together form from 10 to 50 weight percent of the aqueous mixture; and the aqueous mixture has a pH of 1.5 to 3.5.

2. The composition of claim 1 wherein the first copolymer comprises from 5 to 15 weight percent of mer units derived from a C 1 -C 2 alkyl acrylate and the second copolymer comprises from 3 to 10 weight percent of mer units derived from C 4 -C 5 alkyl acrylate.

3. The composition of claim 2 wherein the first copolymer comprises a first copolymer comprising mer units of methyl acrylate and vinylidene chloride; and the second copolymer comprises mer units of butyl acrylate and vinylidene chloride.

4. The composition of claim 2 wherein the first and second copolymers are in a weight ratio of 90:10 to 60:40 and the first and second copolymers together comprise from 10 to 30 weight percent of the aqueous mixture.

5. The composition of claim 2 wherein the first and second copolymers are in a weight ratio of 50:50 to 10:90 and the first and second copolymers together comprise from 25 to 50 weight percent of the aqueous mixture.

6. The composition of claim 1 wherein the first copolymer comprises a first copolymer comprising mer units of methyl acrylate and vinylidene chloride; and the second copolymer comprises mer units of butyl acrylate and vinylidene chloride.

7. The composition of claim 1 wherein the first and second copolymers are in a weight ratio of 90:10 to 60:40 and the first and second copolymers together comprise from 10 to 30 weight percent of the aqueous mixture.

8. The composition of claim 1 wherein the first and second copolymers are in a weight ratio of 50:50 to 10:90 and the first and second copolymers together comprise from 25 to 50 weight percent of the aqueous mixture.

9. The composition of claim 8 wherein the first and second copolymers are in a weight ratio of from 30:70 to 35:65.

10. A method of inhibiting moisture vapor emission from the surface of a concrete structure and enhancing interfacial adhesion between the concrete surface and a covering thereon comprising applying to the concrete surface an aqueous mixture of at least one first copolymer comprising mer units derived from vinylidene halide and mer units derived from C 1 -C 2 alkyl acrylate, said mer units derived from C 1 -C 2 alkyl acrylate being present in from 5 to 40 weight percent of the first copolymer; and at least one second copolymer comprising mer units derived from vinylidene halide and mer units derived from C 4 -C 5 alkyl acrylate, said mer units derived from C 4 -C 5 alkyl acrylate being present in from 3 to 40 weight percent of the second copolymer, wherein said first copolymer and said second copolymer are in a weight ratio of 90:10 to 10:90; the first and second copolymers together form from 10 to 50 weight percent of the aqueous mixture; and the aqueous mixture has a pH of 1.5 to 3.5; said aqueous mixture substantially uniformly applied to the surface to distribute a coating having from 0.4 to 4 kg of copolymer mixture per 14 m 2 of free surface of the concrete structure.

11. The method of claim 10 wherein the first copolymer comprises from 5 to 15 weight percent of mer units derived from a C 1 -C 2 alkyl acrylate and the second copolymer comprises from 3 to 10 weight percent of mer units derived from C 4 -C 5 alkyl acrylate.

12. The method of claim 11 wherein the first copolymer comprises a copolymer of methyl acrylate and vinylidene chloride; and the second copolymer comprises a copolymer of butyl acrylate and vinylidene chloride.

13. The method of claim 11 wherein the first and second copolymers are in a weight ratio of 90:10 to 60:40 and the first and second copolymers together comprise from 10 to 30 weight percent of the aqueous mixture; said aqueous mixture is substantially uniformly applied to the surface to distribute from 0.4 to 2.3 kg of copolymer mixture per 14 m 2 of free surface of the concrete structure.

14. The method of claim 11 wherein the first and second copolymers are in a weight ratio of 50:50 to 10:90 and the first and second copolymers together comprise from 25 to 50 weight percent of the aqueous mixture; said aqueous mixture is substantially uniformly applied to the surface to distribute from 1.8 to 4 kg of copolymer mixture per 14 m 2 of free surface of the concrete structure.

15. The method of claim 10 wherein the first copolymer comprises a copolymer of methyl acrylate and vinylidene chloride; and the second copolymer comprises a copolymer of butyl acrylate and vinylidene chloride.

16. The method of claim 10 wherein the first and second copolymers are in a weight ratio of 90:10 to 60:40 and the first and second copolymers together comprise from 10 to 30 weight percent of the aqueous mixture; said aqueous mixture is substantially uniformly applied to the surface to distribute from 0.4 to 2.3 kg of copolymer mixture per 14 m 2 of free surface of the concrete structure.

17. The method of claim 16 wherein the aqueous mixture is applied by multiple applications.

18. The method of claim 10 wherein the first and second copolymers are in a weight ratio of 50:50 to 10:90 and the first and second copolymers together comprise from 25 to 50 weight percent of the aqueous mixture; said aqueous mixture is substantially uniformly applied to the surface to distribute from 1.8 to 4 kg of copolymer mixture per 14 m 2 of free surface of the concrete structure.

19. The method of claim 18 wherein the first and second copolymers are in a weight ratio of from 30:70 to 35:65 and the aqueous mixture is applied in a single application.

20. A method of inhibiting loss of water from an uncured or partially cured concrete structure comprising applying to the concrete surface an aqueous mixture of at least one first copolymer comprising mer units derived from vinylidene halide and mer units derived from C 1 -C 2 alkyl acrylate, said mer units derived from C 1 -C 2 alkyl acrylate being present in from 5 to 40 weight percent of the first copolymer; and at least one second copolymer comprising mer units derived from vinylidene halide and mer units derived from C 4 -C 5 alkyl acrylate, said mer units derived from C 4 -C 5 alkyl acrylate being present in from 3 to 40 weight percent of the second copolymer, wherein said first copolymer and said second copolymer are in a weight ratio of 90:10 to 10:90; the first and second copolymers together form from 10 to 50 weight percent of the aqueous mixture; and the aqueous mixture has a pH of 1.5 to 3.5; said aqueous mixture substantially uniformly applied to the surface to distribute a coating having from 0.4 to 4 kg of copolymer mixture per 14 m 2 of free surface of the concrete structure.

21. The method of claim 20 wherein the first copolymer and second copolymer are in a weight ratio of 50:50 to 10:90.

22. The method of claim 20 wherein the first copolymer and second copolymer are in a weight ratio of 35:65 to 10:90 and the first copolymer comprises mer units derived from methyl acrylate and vinylidene chloride; and the second copolymer comprises mer units derived from butyl acrylate and vinylidene chloride.