Enhancing the performance of lightweight high-performance concrete through an alternative pre-wetting method for lightweight aggregates using simulated cement pore solution

Abstract

Lightweight aggregates (LWAs) are typically pre-wetted to prepare lightweight concrete. However, the incorporation of pre-wetted LWAs by water, may dilute the pore solutions of the cement matrix surrounding the LWAs during the process of internal curing. To this end, this paper proposes an alternative pre-wetting method for LWAs using simulated cement pore solutions (saturated Ca(OH)2 or real cement solution) instead of water. The effects of LWAs pre-wetted by various agents on the performance of lightweight high-performance concrete (LW-HPC) were investigated and compared. Experimental results confirmed that water released from LWAs diluted the pore solutions of cement in LW-HPCs. By using cement solution and Ca(OH)2 solution, the compressive strengths of LW-HPCs were respectively increased by 41.7% and 28.2% at 3d, and 11.6% and 3.2% at 28d compared with LWAs pre-wetted by water only. Among the three pre-wetting agents, the saturated cement solution was found to be the optimal one for promoting the hydration of cement, elastic modulus of the interfacial transition zone, and compressive strength.