Fundamental properties of powder, paste and mortar of surface modified cement and process of the surface modification

摘要

The cement particles which were modified to a round-shape were prepared by a dry impact blending method in which the surface of the cement particles were modified by strong impact. The properties of the powder, paste and mortar of surface modified cement (namely spherical cement), which was prepared in most suitable treatment time (20 min), were examined. As a result, it was found that the cement was more fluid than normal portland cement, and that the water/cement ratio was decreased by 10 wt./100. In addition, the process for formation of the surface modified cement was presumed to be embedding of fine cement particles under 3 pm onto other larger core particle surfaces. Furthermore, though a decrease in the crystallinity of the cement and the dehydration of the gypsum in the cement took place due to the surface modification of the cement particles, the amount of change was slight. The hardened mortar of surface modified cement was approximately 45% stronger than that of normal portland cement.