PURPOSE: To provide a cement admixture enhancing the flowability of a cement mixture, reduced in the amount of entrained air and effective for preventing the slump loss of the cement product.
CONSTITUTION: A cement mixture containing at least one salt selected from the group consisting of alkali metal salts, ammonium salts and amine salts derived from a copolymer obtained by reacting a light oil fraction containing indene as a main component with an unsaturated dicarboxylic acid anhydride having an olefinic double bond, the component having a mol. wt. of ≤2000 being contained in the salt in an amount of ≤4.0 area % measured by a gel- permeation chromatography method. At least one kind of the salt selected from a naphthalenesulfonic acid-formaldehyde condensation product salt, a melamine resin sulfonate salt, and a lignin sulfonate salt may further be added.
ENOMOTO NORIHIDE
NARUSE YOSHIHIRO
OOTSU KIMIYO
