Physical and dynamic mechanical behaviors of marble after heat treatment in quasi-vacuum and air-filled environments

The dynamic mechanical properties of rock specimens after thermal treatment in the air-filled environment (AE: i. e., at the free surface) have been extensively investigated, yet they are rarely estimated in the quasi-vacuum environment (VE: i. e., far from free surface), which is of special importance in engineering practice. Several precise laboratory tests(i. e., split Hopkinson pressure bar test) on marble samples in both AE and VE were performed to investigate physical and dynamic mechanical behaviors of marble after heat treatment (25 °C to 900 °C) in AE and VE. The tests results demonstrate that related properties of marble could be divided into three different stages by corresponding critical temperatures of 300 °C and 600 °C, at which heat damage factors are 0.29 (0.30) and 0.88 (0.92) in VE (AE), respectively. The thermal damage developes more fully in AE than in VE. The thermal environment plays an important role, especially in Stage 3. Specifically, a conspicuous difference (greater than 20%) between AE and VE occurs in corresponding dynamic strength and the anti-deformation capacities of tested marble specimen. The influence of heat damage of rock is very important and valuable in engineering practice, particularly when the temperature is very high (greater than 600 °C).