Effects of temperature and basalt fiber on the mechanical properties of geopolymer concrete under impact loads of different high strain rates

The high-temperature impact test was carried out on basalt fiber reinforced geopolymer concrete (BFRGC) using the high-temperature split Hopkinson pressure bar test system at 25 degrees C-800 degrees C, and the effects of temperature and basalt fiber on the dynamic mechanical properties of geopolymer concrete (GC) were studied. The results show that the dynamic compressive strength (fcd), dynamic compressive strength increase factor (DIF), peak strain (& epsilon;) and specific energy absorption (SEA) of BFRGC have strain rate effect at different temperatures. The fcd and SEA of BFRGC have temperature reinforcement effect and high-temperature damage effect, and the & epsilon; shows a significant temperature plasticizing effect. With the increase of temperature, the fcd and SEA of BFRGC first increase and then decrease, and the & epsilon; increases continuously. The temperature threshold of the fcd of BFRGC is 400 degrees C. And when the temperature is 200 degrees C, the fcd, SEA and DIF of BFRGC are the maximum, and the strength characteristic, energy absorption characteristic and strain rate sensitivity of fcd of BFRGC are the best. The addition of appropriate basalt fiber can improve the dynamic mechanical properties of GC at room temperature and high temperature. When the fiber content is 0.1%, the dynamic mechanical properties and the strain rate sensitivity of fcd of BFRGC at different temperatures are better.