Study on the Characteristics of Grinding Activation of Fly Ash and Its Influence on Cement Cementitious System

Abstract

This study takes fly ash of a coal-fired power plant as the research object, the pulverized and activated fly ash was processed by ball milling process. The difference of physical and chemical properties of fly ash before and after pulverized and activated treatment and its influence mechanism on cement cementitious system were studied by a series of characterization analysis methods. The results show that pulverized fly ash activation significantly reduces the particle size of fly ash, increases its specific surface area, and decreases the crystallinity of crystal minerals and anionic polymerization degree of internal silicon aluminate substance in fly ash, thus reaching the deep activation effect of fly ash activity. Fly ash powder can promote the compressive strength of test block more than fly ash original ash, especially the early compressive strength of test block. The experimental results of water absorption and thermogravimetry show that the effect of fly ash powder on test block is mainly to improve the compactness of test block, reduce its porosity. At the same time, accelerating the secondary hydration reaction of cement is bound to produce more C–S–H gel, thus improving the mechanical properties of test block.