Systematic evaluation of cracking behavior in specimens containing single flaws under uniaxial compression

This paper presents the results of an experimental study in which molded gypsum and Carrara Marble specimens containing a pre-existing flaw were tested in uniaxial compression. The main purpose of this study was to observe and characterize the cracks that emanate from a single pre-existing flaw. Seven different crack types were identified based on their geometry and propagation mechanism (tensile/shear). Specifically, they include three types of tensile cracks, three types of shear cracks, and one type of mixed tensile–shear crack. In addition to the geometry and mechanism, it was also possible to determine the temporal sequence of different crack types. These observations form the basis for a re-evaluation of cracking processes reported in the literature. It is possible to apply the classification obtained in the present research to previously conducted experiments by others. This eliminates much of the confusion that has existed when comparing different research results.