FINE POWDER FOR CEMENT MIXING

摘要

PROBLEM TO BE SOLVED: To obtain a high-strength hardened body while showing excellent fluidity even under conditions of use with a low water cement ratio by using fine powder of mineral substance having a prescribed specific surface area and a specified average particle diameter for cement mixing. SOLUTION: Fine powder of mineral substance having 5-20 m2/g specific surface area by a BET method and <=2μm weight-average particle diameter based on a particle size distribution in an amount of 0.03-0.4 vol. part based on 1 vol. part of cement is used as fine powder for cement admixture. Effectively the fine powder for cement admixture has <=0.25 water cement ratio and is used under conditions of use of a high-performance water reducing agent. The fine powder for cement acimixture simultaneously satisfying the specific surface area and the average particle diameter is close to a sphere, is suitable for exhibiting a ball bearing effect and provides excellent workability. Siliceous fine powder is preferable as a material for the fine powder for cement admixture. The siliceous fine powder promotes strength by a pozzolanic reaction with cement.