Patent ID: 6858661

Claim:
An admixture system for modifying hydratable cementitious compositions, comprising: (A) a water reducer comprising a polycarboxylic acid or salt or derivative thereof; and (B) a tertiary amine defoamer having the structural formula R 1 NR 2 R 3 wherein R 1 is hydrophobic and represents a C 8 -C 25 group comprising a linear or branched alkyl, alkene, alkyne, alcohol, ester or oxyalkylene group, the oxyalkylene group having the chemical structure R 4 —(AO) n — or R 4 —(OA) n — wherein R 4 represents hydrogen or a C 1 to C 25 alkyl group, A represents a C 1 to C 6 alkyl group and “n” is an integer of 1 to 4; and R 2 and R 3 each represent a C 1 -C 6 group comprising a linear or branched alkyl, alkene, alkyne, alcohol, ester or oxyalkylene group, the oxyalkylene group having the chemical structure R 4 —(AO) n — or R 4 —(OA) n — wherein R 4 represents hydrogen or a C 1 to C 25 alkyl group, A represents a C 1 to C 6 alkyl group, and “n” is an integer of 1 to 4; wherein said average molecular weight of said tertiary amine defoamer is no less than 100, and wherein said average molecular weight of said tertiary amine defoamer is no greater than 1500.