| 摘要 |
PURPOSE:To improve strength-exhibiting characteristic and stability of a quick hardening cement at low temp. and to prevent a reaction between alkali and aggregate by mixing a specified clinker, Portland cement clinker, II type anhydrous gypsum, Li2CO3, and a hydroxycarboxylic acid. CONSTITUTION:(A) 20-60wt.% clinker consisting primarily of calcium sulfoaluminate, (B) 20-70wt.% Portland cement clinker, are mixed with (C) about 60wt.% portion of 0.5-30wt.% II type anhydrous gypsum, and the mixture is crushed, wherein the Blaine value of the component (C) is regulated to 7,000-12,000cm<2>/g. Then, about 40wt.% portion of said component (C) (constituting 0.5-30wt.% portion of the whole compsn.) being coarse powder and having <=3,000cm<2>/g Blaine value, (D) 0.1-3.0wt.% Li2CO3 having >=5,000cm<2>/g Blaine value, and (E) 0.05-2wt.% hydroxycarboxylic acid such as citric acid, etc. are mixed so as to obtain 1.4-1.0 molar ratio of SO3/Al2O3 in the chemical composition of a cement. |
