| 摘要 |
A cement additive composition for preventing discoloration of the surface of concrete, comprising a cement additive (a) and a water-reducing admixture (b), the additive (a) comprising a mixture of compounds represented by the general formula (1):(wherein R1 is a C1-6 alkyl group, A is an ethylene group and/or a propylene group, and n1 is a number of 1 or more), containing all the compounds satisfying n1=2 to 6 in a total amount of not less than 40% by mass, and having an average n1 of 1.5 to 10, a molecular weight distribution Mw/Mn of not less than 1.05, a Z average molecular weight Mz of not less than 200 and a ratio of (a):(b) by mass of (5 to 99.5):(95 to 0.5). It can prevent the discoloration of the surface of concrete.
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