Improving durability of heat-cured high volume fly ash cement mortar by wet-grinding activation

Abstract

This work investigated the durability performances of heat-cured high volume (30 wt%–70 wt%) fly ash (FA) cement mortars by using different particle sizes (19.7 μm, 4.29 μm and 2.51 μm) and amounts of wet-grinded fly ash slurries. Wet-grinding technology was used to prepare ultrafine fly ash slurry and improve the durability of heat-cured high volume fly ash cement mortar. Results indicated that the smaller the particle size of wet-grinded fly ash, the better the durability improvement effect of heat-cured high volume fly ash blended mortar. Autogenous shrinkage was increased with the reduced particle size of wet-grinded fly ash. Sulfate attack resistance coefficient, capillary water absorption and electric flux of heat-cured high volume FA mortar were efficiently decreased by wet-grinded FA, within 50 wt% content. As for carbonation resistance, lower carbonation depth than the reference mortar was observed with wet-grinded F3 content of 30 wt%. Results highlight that wet-grinding treatment of fly ash could provide an efficient way to improve the durability performance of heat-cured high volume fly ash composites.