Admixture of cement composition

Abstract

An additive for an admixture of a cement composition, especially, a retarder of a cement composition, capable of exhibiting excellent retardation effect with a smaller addition amount and easily controlling the retardation time by adjusting the addition amount. An admixture of a cement composition, comprising a cement and at least one iminodiacetic acid or salt thereof represented by formula (I): wherein the M groups each independently represents a hydrogen atom, an alkali metal atom, an ammonium group or a substituted ammonium group; Y represents a divalent alkyl group having from 1 to 5 carbon atoms and the divalent alkyl group may be substituted by a hydroxyl group or a COOM group wherein M represents a hydrogen atom, an alkali metal atom, an ammonium group or a substituted ammonium group; and W represents a hydrogen atom, a hydroxyl group or a COOM group wherein M represents a hydrogen atom, an alkali metal atom, an ammonium group or a substituted ammonium group.

Dependencies are inferred from the claim text.