Dispersing agent for high-flow or self-compacting concrete

摘要

Cement dispersing agents for self-compacting concrete of high flowability, comprising a water-soluble N-vinyl copolymer, prepared by copolymerizing (a) an N-vinyl-lactame or -amide with (b) a polyethylene glycol ester of maleic acid containing 6 to 240 moles of oxyethylene groups per molecule and (c) at least one monomer selected from among unsaturated dicarboxylic acids and (d) methallylsulfonic acid. When an aqueous solution of this copolymer is used as an admixture to freshly prepared concrete of even extremely low water-to-cement ratio, a high fluidity, a low decrease in flowability with the progression of time and a lack of segregation over time is attained.