| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a cement additive which is little in the decrease of long-term strength expression property even when the addition amount of the additive to cement increases to 10 mass% or more, and a cement composition formed by adding the cement additive. <P>SOLUTION: The cement additive comprises 2CaO-SiO<SB>2</SB>and 2CaO-Al<SB>2</SB>O<SB>3</SB>-SiO<SB>2</SB>as indispensable components, has a total alkali of 0.1-2.0 mass% and contains 10-100 pts.mass of 2CaO-Al<SB>2</SB>O<SB>3</SB>-SiO<SB>2</SB>+4CaO-Al<SB>2</SB>O<SB>3</SB>-Fe<SB>2</SB>O<SB>3</SB>relative to 100 pts.mass of 2CaO-SiO<SB>2</SB>, and the cement additive is formed by crushing a fired material containing 20 pts.mass or less of 3CaO-Al<SB>2</SB>O<SB>3</SB>. The cement composition contains 50 mass% or less of the cement additive to the total of the cement additive and cement. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
