| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a composition capable of giving hardening improved in stripping strength even if the pre-aging time is shortened by containing Portland cement and a specific quantity of an insoluble anhydrous gypsum having fluorine of content equal to or below a specific quantity. SOLUTION: The cement composition contains Portland cement, 1-3 wt.% insoluble anhydrous gypsum having <=1.0 wt.% total fluorine content per the composition and in addition to these essential components, 15-40 wt.% inorganic admixture selected from blast furnace slag fine powder, flyash, lime stone fine powder and the like and having 2,000-10,000 cm<2> /g Blaine specific surface area per the composition. When in use, an aggregate, a chemical admixture and the like such as a water reducing agent such as polycarboxylic acid or a high performance AE water reducing agent and water are added into the composition and kneaded to mold a mortar or concrete. A cement hardened body excellent in strength property is obtained by steam aging for 2-5 hr after pre-aging the molding for 20-60 min.</p> |
