| 摘要 |
PROBLEM TO BE SOLVED: To obtain a cement admixture which efficiently produces a shrinkage reducing effect as well as a superior fluidizing effect and a water reducing effect by incorporating monomers having specified structure as copolymerizable monomer components. SOLUTION: The cement admixture contains a monomer (a) of formula I [where R1 and R2 are each H or methyl; X is O, CH2O or COO; and (m) is 7-100], e.g. a polyoxyethylene (meth)allyl ether, a monomer (b) of formula II [where R3 is H or methyl; R4 is a 1-24C hydrocarbon; Y is O or CH2O; A is a 2-4C alkylene oxide; (n) is 1-4 when R4 is 1C hydrocarbon and (n) is 2-100 when R4 is a 2-24C hydrocarbon], e.g. polyoxyethylene methylvinyl ether, a monomer (c) which is an unsaturated polycarboxylic acid or its salt, e.g. maleic anhydride and a monomer (d) which is a sulfonic acid-containing monomer, e.g. vinylsulfonic acid. |
