Influence of elevated temperatures on mode I and mode II fracture toughness and fracture energy of nanoclay reinforced polymer concrete

Depending on the type of application, polymer concrete (PC) may be exposed to high temperatures. Therefore, it is important to investigate the influence of exposure to elevated temperatures on the fracture mechanics of PC. For this purpose, the PC composed of epoxy as resin, silica sand and crushed basalt as aggregates, and nanoclay as nanofiller is synthesized. The prepared PC is exposed to temperatures of 24, 40, 60, 80, 100, 120, and 140°C for two hours, and the residual fracture toughness and fracture energy in mode I and mode II are studied. Three-point bending test is conducted on cracked semi-circular bend specimens with the crack angle of 0° (pure mode I) and 41° (pure mode II) to determine the fracture parameters. Subjecting to high temperatures significantly increased the fracture toughness and fracture energy of the PC. The maximum fracture toughness and fracture energy are obtained after exposure to 120°C and 140°C, respectively. Scanning electron microscope (SEM) micrographs are used to investigate the fracture surface of the PC. The results of the present experimental research are useful in understanding the fracture mechanics behavior of PCs in mode I and mode II after being subjected to high temperatures.