| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a cement additive which hardly deteriorates strength development even when the amount of addition to cement is made to be 10 mass% or more, moreover, can reduce heat of hydration, can improve fluidity and can reduce drying contraction, and to provide a cement composition made by adding the cement additive. <P>SOLUTION: The cement additive is obtained by grinding fired material which indispensably consists of 2CaO-SiO<SB>2</SB>and 2CaO-(Al<SB>2</SB>O<SB>3</SB>)x-(Fe<SB>2</SB>O<SB>3</SB>)<SB>1-x</SB>-SiO<SB>2</SB>(0≤x≤1), has a content of 2CaO-SiO<SB>2</SB>of 50 mass% or more and has a content of 2CaO-SiO<SB>2</SB>+2CaO-(Al<SB>2</SB>O<SB>3</SB>)<SB>x</SB>-(Fe<SB>2</SB>O<SB>3</SB>)<SB>1-x</SB>-SiO<SB>2</SB>of 92 mass% or more. The cement composition comprises the cement additive of 50 mass% or less with respect to the cement not containing the cement additive therein. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
