Structural evolution and reaction mechanisms of alkali-activated slag with diverse Mg/Si ratios: A view from the nanoscale

This study addresses the limited understanding of the polymerization process of alkali-activated furnace slag at the nanoscale. The key problem lies in the unclear role of different Mg/Si ratios and the lack of detailed knowledge about the reaction mechanisms involved. By integrating molecular dynamics simulations and firstprinciples calculations, we explore the structural evolution and reaction mechanisms during the polycondensation reactions of [SiO2(OH)2]2 , [SiO(OH)3] , and [Al(OH)a] in alkali-activated blast furnace slag (AAS) with varying Mg/Si molar ratios (0.05-0.30). Our results reveal the relationship between the Mg/Si ratio and the reaction rate and product formation, and uncover the electronic-level mechanisms underlying the polycondensation reactions. This research provides valuable insights into the reaction process at the molecular level, which is essential for understanding and optimizing the performance of AAS gels, a promising sustainable building material.