Multi-scale modeling and experimental investigations of geopolymeric gels at elevated temperatures

Geopolymers are an emerging class of cementitious binders formed by aluminum–silica rich activating materials. Experimental results indicate that geopolymer concrete is relatively stable at elevated temperatures, and could be possibly utilized in applications such as nozzles, aspirators and refractory linings. Geopolymer grouts with a Si:Al ratio of about 2:1 exhibited superior performance at elevated temperatures than lower geopolymer grouts, with lower Si:Al ratio. Sodium-alumino-silicate-hydrate and potassium-alumino-silicate-hydrate are primary products of geopolymer gels, and models of those systems were investigated using density functional theory, molecular mechanics and molecular dynamics in order to elucidate their behavior at different temperatures and varying Si:Al ratios.

► Multiscale modeling and experimental evaluation of fly ash based geopolymeric gels. ► The system was studied using DFT, MM and MD for varying silica to alumina ratios. ► Atomistic structure of geopolymer K-A-S-H and N-A-S-H structures was performed. ► N-A-S-H with Si:Al, 2:1 was found to exhibit superior performance. ► Geopolymer concrete can be used effectively at elevated temperatures.