Comparison of the Kaiser effect in marble under tensile stresses between the Brazilian and bending tests

This article demonstrates that other than the preexisting compressive stress, it is possible to measure preexisting tensile stress in marble using the Kaiser effect method. To assess the reliability of the Kaiser effect method in measuring tensile stress, cyclic loading-unloading cycles with increasing peak stress were applied to marble samples to conduct Brazilian and bending tests. The readings of the stress, strain and acoustic signal were recorded by an automatic data acquisition system, and the result confirmed that the Kaiser effect was observed. In all tests, the Felicity ratios were between 0.92 and 1.2, but the bursting of acoustic emission was more pronounced in the bending test. The less distinct Kaiser effect in the Brazilian test could be caused by the complex stress distribution/crack propagation.