Impact behaviours of engineered geopolymer composite exposed to elevated temperatures

Abstract

Engineered geopolymer composite (EGC) is a novel fiber reinforced geopolymeric material with ultra-high ductility, which is more eco-friendly than engineered cementitious composite (ECC) due to the substitution of cement. This paper was intended to investigate the impact behaviours of EGC exposed to elevated temperatures. The ambient cured EGC with local PVA fibers was first designed and tested under compressive and flexural loading conditions. The comparisons between ECC and EGC were made concerning the compressive and flexural behaviours. Then, the drooping hammer tests of EGC, ECC, cement and geopolymer matrixes were conducted under different environment temperatures, i.e., 50 °C, 100 °C and 150 °C. As the temperature increased from 50 °C to 150 °C, the impact resistance of cement decreased while the impact resistance of geopolymer increased gradually. It was also found that EGC has higher maximum impact load and impact duration than ECC as the environment temperature increased, indicating that EGC may be more suitable for the impact protection of structures under high temperatures. At the environment temperature of 50 °C, the energy dissipation capacity of EGC increased with the increase of alkali concentration, while the alkali concentration was recommended to be lower than 12 mol/L when the environment temperature is above 100 °C.