Experimental investigation of the temperature-dependent dissolution process of aluminosilicate glass and low-calcium supplementary cementitious materials under alkaline conditions

Abstract

High-temperature curing is commonly employed to promote the pozzolanic activity of supplementary cementitious materials (SCMs) in cementitious systems. Herein, the temperature-dependent dissolution processes of low-calcium SCMs and synthesised aluminosilicate glass were examined at pH 13 for cementitious systems. The dissolution rate and thermal activation energy (TAE) were estimated using nonlinear fitting and the Arrhenius equation. Experimental and analytical findings demonstrated that the TAEs of investigated SCMs and aluminosilicate glasses were temperature-dependent, decreasing with increasing temperature. Moreover, the TAE of aluminosilicate glasses increased with increasing Al/Si ratio, mainly due to the higher TAE of Al2O3 compared to SiO2. In addition, the TAE of fly ash was higher than that of investigated glass, largely because the Si and Al coordination numbers increased with decreasing cooling rates, according to molecular dynamics analysis. The topological TAE derived from molecular dynamics analysis is a promising parameter for estimating the TAE of aluminosilicate glass.