| 摘要 |
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, wherein (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): <?in-line-formulae description="In-line Formulae" end="lead"?>Lm=(Ln+Mp)/2 (1) <?in-line-formulae description="In-line Formulae" end="tail"?> (5) the peak area between the elution times Lm and Ln is designated as P<SUB>0 </SUB>and the peak area between the elution times Lh and Mp as Q<SUB>0</SUB>, P<SUB>0 </SUB>and Q<SUB>0 </SUB>satisfying the following Formula (2): <?in-line-formulae description="In-line Formulae" end="lead"?>15<=(P<SUB>0</SUB>x100)/(P<SUB>o</SUB>+Q<SUB>0</SUB>)<=45 (2). <?in-line-formulae description="In-line Formulae" end="tail"?>
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