Copolymer admixture system for workability retention of cementitious compositions

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 at least one 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, wherein at least one Component A comprises a hydroxyalkyl monoester, hydroxyalkyl diester or mixtures thereof;
• and,
• at least one of:
• Component B comprising at least one ethylenically unsaturated alkenyl ether monomer comprising at least one C2-4 oxyalkylene side group of about 1 to 30 units;
• or,
• Component C comprising at least one ethylenically unsaturated alkenyl ether monomer comprising at least one C2-4 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.