Mechanical behaviors of metakaolin-based foamed geopolymer (MKFG) under dynamics loading

In this study, metakaolin-based foam geopolymer (MKFG) with densities of 400 kg/m³, 600 kg/m³, and 800 kg/m³ were prepared. The effect of weak links on the dynamic mechanical behavior, damage morphology, and energy absorption capacity (SEA_p) of the MKFG was studied by X-CT analysis, Split Hopkinson Pressure Bar (SHPB) test, and fractal analysis. The results show that the connected porosity of MKFG rises with decreasing density. The sensitivity of the damage level to strain rate decreases with elevated connected porosity, which is because the stress concentrations caused by weak links. The amplifying effect of strain rate on the dynamic compressive strength of MKFG diminishes as the connected porosity increases. The sensitivity of SEA_p to the damage level rises with a decrease in the connected porosity. Finally, the simulation results corroborate that the distribution of connected pores has a significant influence on the damage process of the MKFG.