The impacts of calcium acetate on reaction process, mechanical strength and microstructure of ordinary Portland cement paste and alkali-activated cementitious paste

The gentle corrosion of acetic acid is frequently utilized to modify recycled concrete aggregates for improving concrete performance, but there is a lack of research on the effect of its process product, calcium acetate (CA), on the properties of cementitious materials. The reason for this work is to discover the role of CA in ordinary Portland cement, alkali-activated low-calcium and high-calcium cementitious materials, and to investigate its possibility as chemical admixture. The impacts of CA on the reaction process, compressive strength, and microstructure of diverse cementitious materials were mainly studied. The results appeared that the impacts of CA on diverse cement are different. The performance of ordinary Portland cement paste depended on the content of calcium acetate. The content of 0.25 wt% CA can increase the reaction degree of cement, improve strength and microstructure of cement paste. In alkali-activated low-calcium fly ash paste, the positive impact of Ca2+ dis-solved from calcium acetate was obvious. With the increment of CA content, their strength improvement and microstructure characteristics were optimized. The reaction process of alkali-activated high-calcium slag paste was hindered by calcium acetate, which resulted in the deterioration of strength, the increase of porosity and pore fractal dimension, as well as the relatively uncompacted microstructure. Based on the results, calcium acetate can be used as an admixture, but the content needs to be controlled according to the characteristics of cementitious materials.