| abstract |
An object of the present invention is to provide a polycarboxylic acid polymer for blending in cement for a cement composition superior both in dispersion and dispersibility-retention. The object was achieved by providing the present invention of a polycarboxylic acid polymer for blending in cement, n whereinn (1) the molecular-weight distribution curve of the polycarboxylic acid polymer is drawn by measuring the molecular weight distribution thereof with gel permeation chromatography and plotting elution times on the abscissa, (2) a base line is drawn on the molecular-weight distribution curve, (3) the elution-starting time, elution-ending time, and peak-top time of the peak corresponding to the polymer component are respectively designated as Lh, Ln, and Mp; (4) Lm is calculated according to the following Formula (1): nn Lm =( Ln+Mp )/2 (1)n (5) the peak area between the elution times Lm and Ln is designated as P 0 and the peak area between the elution times Lh and Mp as Q 0 ,n nP 0 and Q 0 satisfying the following Formula (2):n nn 15≦( P 0 ×100)/( P 0 +Q 0 )≦45 (2). |