Abstract: It is well known that rock materials have different mechanical behaviors under the compressive and tensile loading. Correspondingly, there are two types of elastic modulus; they are compressive elastic modulus Ec, and tensile elastic modulus Et, respectively. In order to distinguish which indirect test methodologies, including three-points bending test and Brazilian disc test, is more suitable to measure the tensile elastic modulus Et of rock materials, a series of experimental tests, including uniaxial compressive test (UCT), direct tensile test (DTT), three-points bending test, as well as the Brazilian disc test is performed for three typical types of rock: white marble, granite and sandstone. Based on these experimental results, comprehensive comparative investigation on the reliability of these measurement methods for tensile elastic modulus Et of rock materials is systematically conducted. Finally, it is found that the Brazilian disc test could be a suitable and reliable method to measure the tensile elastic method of rock materials, due to the excellent agreement with that measured by direct tension tests, and due to the simplicity of sample preparation, as well as test operation.

Key words: tensile elastic modulus, direct tensile test, elastic modulus of rocks, three-points bending test, Brazilian disc test