Mechanical Properties of Marble with Varying Slenderness Ratios after High Temperatures

Mechanical properties of rock are affected by the specimen slenderness ratios. However, the temperature-dependent nature of rock with different slenderness ratios have not been investigated. To better understand the relationship of slenderness rations and temperature, marble specimens with four slenderness ratios are used to perform uniaxial compressive test after exposure to four different treatment temperatures. Elastic modulus first increases as slenderness ratio increases from 0.5 to 2, followed by a drop as it increases to 4. Peak strain slightly increases with the increase in the treatment temperature. All specimens exhibit a brittle failure, and the brittleness is more pronounced for those with larger slenderness ratios, while the rising treatment temperature changes the rock failure from brittle to slightly ductile. Rock strength decreases as the specimen slenderness ratio increases. A new correction equation accounting for the treatment temperature is proposed to evaluate uniaxial compressive strength. Four failure modes of the rock are observed, including cone-shaped, splitting, shearing, and mixed. The influence of slenderness ratio on rock strength may be associated with the stress difference inside the specimen, and the thermal damage mechanisms can be attributed to dehydration and chemical actions and nonuniform expansion and shrinkage of minerals during the process of heating and cooling.