Biaxial Loading of Brazilian Disc Samples

Abstract The Brazilian test method has been widely used over the past 50 years to determine the indirect tensile strength of brittle materials, such as rocks and concrete. While the behaviour of Brazilian samples under conventional indirect tensile testing has been the subject of much research, the biaxial loading of a Brazilian sample under both horizontal and vertical compressive forces has rarely been studied. This study investigates the ultimate strength, crack propagation speed, fracture mode, and damage evolution in sandstone Brazilain samples using high-speed photography methods integrated with a newly designed hybrid biaxial-impact testing facility. The result shows that the samples fail under lower tensile stress than their Indirect Tensile Strength based on the principle of superposition.