Experimental study on uniaxial compressive properties and damage evolution of basalt fiber reinforced concrete after being subjected to high temperature

Abstract

The study investigated basalt fiber reinforced concrete (BFRC) for failure characteristics after being subjected to high temperatures under uniaxial compression. Twenty-five sets of cylindrical BFRC specimens were carried out under different basalt fiber (BF) content and temperature. Based on 3D digital image correlation (3D-DIC) and acoustic emission (AE), the effects of temperature and volume content of BF on the compressive mechanical properties, damage evolution and failure mode of BFRC are analyzed. The results indicate that the proper volume content (0.26%) of BF can improve the compressive strength of concrete. Generally, the uniaxial compressive strength of BFRC decreases with increasing temperature. The internal and external damage evolution trend of BFRC is basically the same, which can be divided into pore compaction stage, stable crack growth stage and unstable crack growth stage. The proper volume content (0.26%) of BF reduces the degree of BFRC damage. The increase in the volume content of BF leads to an increase shear cracks proportion in BFRC, and the failure mode of the main crack gradually changes from tension-shear failure to shear failure. Conversely, the increase in temperature increased the degree of BFRC damage. The internal and external failure modes of BFRC are basically the same. At 20 °C, the failure of concrete without basalt fiber is mainly tensile crack. With the increase of temperature, the main failure mode is tension-shear failure.