Alkali-activated slag mortar molded by non-stirring molding: Compressive strength, hydration properties and microstructures
Tao Sun, Jun Fan, Gaoshang Ouyang, Fang Xu, Ziyan Wang, Weisong Yin, Wanmin Li
Abstract
Alkali-activated slag (AAS) characterized by fast hardening and high early strength has potential application prospects in concrete canvas (CC), where a non-stirring molding method is required to prepare mortar. This paper provides a new method for the preparation of alkali-activated slag mortar (AASM) by non-stirring (sprinkling-molding), where mechanical properties, hydration properties, and microstructures were investigated. The results suggest that the compressive strength of the sprinkling-molding mortar was slightly lower than that of the conventional stirring-molding mortar, and the compressive strength with sodium silicate content of 15 % the slag mass at 28d can reach 44.5 MPa. The hydration products are dominated by amorphous C-A-S-H gels, with small amounts of hydrotalcite. There are differences in degree of hydration and microstructures of each layer in the sprinkling-molding mortar.