Experimental investigation on physical and tensile mechanical properties of granite after different heating/cooling treatments

In this study, a series of physical properties of granite were tested after different cooling treatments. Correspondingly, Brazilian splitting combined with acoustic emission testing was conducted on five groups of granite samples at different temperature levels, and scanning electron microscopy (SEM) was used to investigate the microstructure of granite. It was found that the P-wave velocity, hardness and thermal conductivity decreased with rising temperature. The tensile strength of granite was deteriorated by temperature action, and the progression of cracks was monitored using AE technology. The scanning electron microscopy results also indicated a significant increase in both number and density of cracks in the granite samples subjected to temperature variations compared to the naturally cooled group. In addition, after heating and cooling at different temperatures, samples with lower tensile strength exhibited rougher fracture surfaces, attributing to the generation of more thermal cracks during the heating and cooling processes. Moreover, a variation mechanism for granite after temperature treatment was proposed.