Copolymer admixture system for workability retention of cementitious compositions

摘要

A non-ionic polyether-polyester copolymer for extending workability to a cementitious mixture containing hydraulic cement and water, wherein the copolymer comprises residues of at least the following monomers: Component A comprising an ethylenically unsaturated carboxylic acid ester monomer comprising a moiety hydrolysable in the cementitious mixture, wherein the hydrolyzed monomer residue comprises an active binding site for a component of the cementitious mixture; and, at least one of: Component B comprising an ethylenically unsaturated, carboxylic acid ester or alkenyl ether monomer comprising at least one C2 4 oxyalkylene side group of about 1 to 30 units; or, Component C comprising an ethylenically unsaturated, carboxylic acid ester or alkenyl ether monomer comprising at least one C24 oxyalkylene side group of 31 to about 350 units; wherein the molar ratio of Component A to the sum of the molar ratios of Component B and Component C is about 1:1 to about 10:1.