Fluidity of Spherical Cement and Mechanism for Creating High Fluidity

Abstract

The water/cementitious binder ratio of spherical cement concrete was decreased by 6–8%, and its unit weight of water was decreased by 14–30% in the same level of fluidity as that of normal Portland cement concrete. The superplasticizer dosage could be reduced to a maximum 2/3. The mechanism for the creation of high fluidity was considered as below. 1) The spherical shape is highly effective in increasing fluidity. 2) The particle size distribution, which is distributed in 3–40 μm, contributes to the creation of high fluidity. 3) The adsorption of superplasticizer to spherical cement particle surface decreases by 40% because of a decrease of the specific surface area and localization of the interstitial phase with gypsum. 4) The initial heat evolution amount of spherical cement is smaller by 25% than that of normal Portland cement. This low activity at initial hydration contributes to the creation of high fluidity.