Modified Brazilian Test for Indirect Measurement of Tensile Strength of Brittle Materials

The applicability of a new test method involving semi-circular (truncated) Brazilian disc specimens is examined in this study to effectively eliminate the unwanted high shear stresses at the loading points, as well as the multiple cracking that commonly occurs in the testing of standard Brazilian dicks comprising hard and brittle materials. A series of tests with a wide range of hard and brittle materials, including various types of rocks and ceramics, was carried out. In all tests performed, a single straight plane of fracture was observed. Through finite element numerical modelling and high-speed photography of the fracture process, the rupture mechanism was further confirmed to be the result of an indirect tensile stress induced inside the specimens. Based on the results, it is concluded that truncated Brazilian specimens can conveniently be adopted to determine the tensile strength of a target material, rather than the standard disc profiles in which catastrophic local cracking makes the procedure unreliable.