| 摘要 |
PROBLEM TO BE SOLVED: To provide a cement admixture which is capable of securing a sufficient flowability and working time without using a setting modifier and is capable of achieving a sufficient strength development, even through steam curing or high-temperature-high-pressure curing, and a cement composition. SOLUTION: The cement admixture comprises (A) a ground product of a fired product containing 2CaO-SiO<SB>2</SB>and 2CaO-Al<SB>2</SB>O<SB>3</SB>-SiO<SB>2</SB>, provided that the total amount of 2CaO-Al<SB>2</SB>O<SB>3</SB>-SiO<SB>2</SB>and 4CaO-Al<SB>2</SB>O<SB>3</SB>-Fe<SB>2</SB>O<SB>3</SB>is 10-100 pts.mass against 100 pts.mass 2CaO-SiO<SB>2</SB>and the amount of 3CaO-Al<SB>2</SB>O<SB>3</SB>is≤20 pts.mass and (B) a silica powder. The cement admixture optionally further contains (C) gypsum. COPYRIGHT: (C)2008,JPO&INPIT
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