EFFECT OF ZIRCONIUM DIOXIDE AND ALUMINUM OXOCHLORIDE ADDITIVES ON THE HYDRATION KINETICS OF HIGH-ALUMINA CEMENT, STRUCTURAL-PHASE AND STRENGTH CHARACTERISTICS OF CEMENT STONE

The paper studies the kinetics of hydration of high-alumina cement HAC-70 with ZrO2 and AlOCl additives and their influence on the composition, structure and strength of cement stone. It has been shown that in the presence of ZrO2 (10 wt.%), the rate of cement hydration decreases and the content of hydroaluminates CAH10, C2AH8 and aluminum hydroxide in the hydration products decreases. The addition of aluminum oxochloride AlOCl (0.5 wt.%) accelerates hydration and helps increase the compressive strength of cement stone at the age of 7 days or more. The introduction of ZrO2 into cement promotes the formation of a denser structure of cement stone and an increase in its residual strength during heat treatment in the range of 400-1200°C. It was established that when fused corundum was introduced into the studied cements as a filler, the contact zone between the cement matrix and the filler grains was weak, and cracks formed along it when the sample was loaded. The use of crushed HAC clinker as a filler leads to the formation of a strong contact between the cement matrix and the filler grains, which contributes to a significant increase in the strength of the material.