초록 ▼

The objective of the present invention is to provide a concrete composition in which the amount of air entrained can be maintained stably and which is excellent in strength and durability, a concrete composition which is excellent in freeze-thaw durability owing to the good quality of foams and is e

The objective of the present invention is to provide a concrete composition in which the amount of air entrained can be maintained stably and which is excellent in strength and durability, a concrete composition which is excellent in freeze-thaw durability owing to the good quality of foams and is excellent in air content stability with time and which can form curing products excellent in strength and durability, a method of producing such concrete composition, and a cement admixture.

대표청구항 ▼

The invention claimed is: 1. A concrete composition comprising an defoaming agent, a polycarboxylic acid polymer, cement, water, fine aggregate and coarse aggregate, as essential constituents, wherein said defoaming agent comprises a polyoxyalkylene compound having at least one nitrogen atom within

The invention claimed is: 1. A concrete composition comprising an defoaming agent, a polycarboxylic acid polymer, cement, water, fine aggregate and coarse aggregate, as essential constituents, wherein said defoaming agent comprises a polyoxyalkylene compound having at least one nitrogen atom within the molecule and having an oxyethylene group or groups and an oxyalkylene group or groups containing not less than 3 carbon atoms and further having an aliphatic hydrocarbon structure containing at least 5 consecutively bound carbon atoms; and wherein said polyoxyalkylene compound satisfies the relationship 0.15-1. 4. The concrete composition according to claim 2 wherein said polycarboxylic acid polymer is a coplymer composed of a constituent unit (I') represented by the following general formula (1): wherein R1 represents a hydrogen atom or a methyl group, R2O represents an oxyalkylene group containing 2 to 4 carbon atoms, R3 represents a hydrocarbon group containing 4 to 30 carbon atoms and m represents the average number of moles of the oxyalkylene group added and is 2 to 300, and a constituent unit (II') represented by the following general formula (2): wherein R4 represents a hydrogen atom or a methyl group and M1 represents a hydrogen atom, a univalent metal, a bivalent metal, an ammonium group or an organic amine group, as essential constituent units. 5. The concrete composition according to claim 2, wherein said polycarboxylic acid polymer is one in which R3 in the general formula (1) is a hydrocarbon group containing 4 or 5 carbon atoms and m is 50 to 300. 6. The concrete composition according to claim 2, wherein the mass proportion of water to cement is not more than 50% by mass. 7. The concrete composition according to claim 3, wherein said polycarboxylic acid polymer is a copolymer composed of a constituent unit (I') represented by the following general formula (1): wherein R1 represents a hydrogen atom or a methyl group, R2 O represents an oxyalkylene group containing 2 to 4 carbon atoms, R3 represents a hydrocarbon group containing 4 to 30 carbon atoms and m represents the average number of moles of the oxyalkylene group added and is 2 to 300, and a constituent unit (IT') represented by the following general formula (2): wherein R4 represents a hydrogen atom or a methyl group and M1 represents a hydrogen atom, a univalent metal, a bivalent metal, an ammonium group or an organic amine group, as essential constituent units. 8. The concrete composition according to claim 3, wherein said polycarboxylic acid polymer is one in which R3 in the general formula (1) is a hydrocarbon group containing 4 or 5 carbon atoms and m is 50 to 300. 9. The concrete composition according to claim 4, wherein said polycarboxylic acid polymer is one in which R3 in the general formula (1) is a hydrocarbon group containing 4 or 5 carbon atoms and m is 50 to 300. 10. The concrete composition according to claim 3, wherein the mass proportion of water to cement is not more than 50% by mass. 11. The concrete composition according to claim 4, wherein the mass proportion of water to cement is not more than 50% by mass. 12. The concrete composition according to claim 5 wherein the mass proportion of water to cement is not more than 50% by mass.