Experimental Study of Macroscopic Tensile Fracture Properties of Brittle Rock at High Temperature

The Mode I fracture toughness (K-IC) and the Crack Tip Opening Displacement(CTOD) of rock at high temperature are measured by three-point bending test. The K-IC is increased with the increase of temperature and decreased when the temperature reached its critical value (200 degrees C). The internal structure of rock be changed as the temperature increasing and the other mechanical properties of rock, such as tensile strength, compressive strength, elastic modulus, etc. also show the same law with the K-IC which lead the tensile stress hard to reach its critical value. The CTOD increases with the increasing of temperature until the load reach the peak load and the specimens at different temperatures have the same rule.