A new methodology based on monitoring of crack propagation during small-scale mechanical tests on sawn rock prisms under tension has been developed. The methodology includes a combination of different experimental methods and measuring techniques at different scale levels. Material testing is performed through a tensile stage. Crack monitoring is performed by means of Digital Image Correlation and Acoustic Emission. After the test, microcrack and fracture patterns are studied and quantified in thin-sections using fluorescent light under a petrographic microscope.

By using Digital Image Correlation it is possible to follow crack propagation in relation to the microstructure on the surface of the specimen in a detailed way, whereas Acoustic Emission offers real-time measurement of the crack activity within the specimen. By combining these techniques, it is possible to relate the Acoustic Emission signal characteristics to different phases of the cracking process, such as crack initiation, propagation and bridging of microcracks into macrocracks as well as the creation and localization of the final fracture. After the tensile stage test, crack patterns and the final fractures are studied in detail using polarizing and fluorescence microscopy, establishing the relationship of these. The methodology is practiced to increase the knowledge of critical parameters affecting cracking processes in rock materials and to show how this is related to the material's microstructure as well as mesostructure.