Effects of artificial geopolymer sand as an alternative to natural sand on dynamic mechanical properties of cement mortar

This study aims to prepare cement mortar with different proportions of artificial geopolymer sand (AGS) and investigate its dynamic mechanical properties. Firstly, AGS was used to replace natural sand (NS) to obtain cement mortar with different proportions of AGS (0.0%, 20.0%, 40.0%, 60.0%, 80.0% and 100.0%). Secondly, the dynamic impact test was conducted on cement mortar. The dynamic stress-strain relationship was obtained. Finally, the effects of AGS replacement rate and strain rate on dynamic mechanical properties (dynamic strength, elastic modulus, energy absorption and dynamic increase factor DIF) of cement mortar were discussed. The results show that the dynamic strength, elastic modulus and energy absorption of cement mortar increase firstly and then decrease as replacement rate increases at a fixed impact pressure, while DIF decreases firstly and then increases with replacement rate increasing. The dynamic strength, elastic modulus and energy absorption reach the maximum, the DIF reaches the minimum at the replacement rate of 20.0%. In addition, the dynamic strength, DIF and energy absorption of cement mortar significantly increase as strain rate increases, showing an obvious rate dependence.