Admixture for a hydraulic composition

摘要

Improving fluidity retention of a hydraulic composition involves adding oxycarboxylic acid (a1) and polycarboxylic acid-based dispersant (a2), to hydraulic slurry comprising water and hydraulic powder and having a sulfate ion concentration of 2500 - 40000 (preferably 6000 - 40000) mg/kg. (a2) comprises a polymer having ratio of carboxylic acid monomers not > 30% wt.%.