Effect of nano-silica on hydration, microstructure of alkali-activated slag

Abstract Hydration and micro-structure are important in the study of alkali-activated materials, especially used in building materials. To obtain information about hydration processes, we have investigated the hydration rate and micro-structural evolution. In this research, we evaluated the performances of nano-silica composite, which is produced by adding nano-silica into alkali activated slag. We also tested the impacts of nano-silica on hydration, micro-structure and porosity. Results of the experiments shows that the comprehensive strength is enhanced, the microscopic morphology and hydration characteristics are optimized. Also, hydration rate suggested that the impact of nano-silica on alkali activated slag early hydration is far greater than that of later hydration. Furthermore, the nano-silica action mechanisms on alkali-activated slag discussed in this paper mainly are that the nano-silica supplied siliceous precursor and served as nucleation seed and its accelerated early hydration effects.