| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a cement composition for mortar and concrete which has excellent fluidity, a short kneading time and ultra-high strength developing properties.SOLUTION: A cement composition comprises: 65-90 mass% of Portland cement; 5-15 mass% of silica fume; and 5-20 mass% of fine powder of limestone. The silica fume has a BET specific surface area of 5-18 m/g, and the particle size distribution of the fine powder of limestone is 99 vol.% or more particles of particle sizes of 10μm or smaller, 95 vol.% or more of particles of particle sizes of 5μm or smaller, 70-93 vol.% of particles of particle sizes of 2μm or smaller, 27-50 vol.% of particles of particle sizes of 1μm or smaller and 15 vol.% or less of particles of particle sizes of 0.5μm or smaller.</p> |
