Laboratory Study of the Fracturing Process in Marble and Plaster Hollow Plates Subjected to Uniaxial Compression by Combined Acoustic Emission and Digital Image Correlation Techniques

Hollow plates of plaster and calcitic and dolomitic marbles, extracted from greek quarries, with a single pre-existing cylindrical hole of various diameters are subjected in uniaxial compression. The influence of the material and the hole's diameter on the fracturing process are studied and compared to the literature. Full-field digital image correlation technique and acoustic emission analysis are employed for the monitoring of the fracturing process, the initiation of the main phenomena, their interaction, and the failure mode of the physical models. New precise techniques on the determination of the true time of the primary fracture and spalling initiation by digital image correlation are implemented and presented. The study highlights a new behavioural type of such physical models, with different fracture patterns than those presented in the literature. A comparison between the required applied axial stress for the primary fracture and spalling initiation of the studied materials and the previously published results is presented, showing an exponential relation to the hole's diameter.