Notched marble plates under direct tension: Mechanical response and fracture

The mechanical response of notched marble plates under direct tension is studied experimentally. The motive of the study emerges from the needs of scientists working for restoration of marble monuments, the structural elements of which are often damaged and cracked. The specimens are made of Dionysos marble, used for the restoration of the Athenian Acropolis monuments. The aim of the study is two-folded: Description of the material's overall mechanical response in the presence of macroscopic discontinuities and mapping the damage evolution process. Modern (Digital Image Correlation, Acoustic Emissions, Ultra High Speed Camera) and traditional sensing techniques were used in a combined manner. Concerning the overall mechanical response it was concluded that the size effect is extremely pronounced while the critical Notch Opening Displacement appears inappropriate as a fracture parameter. Analysis of the data pumped with the aid of the Acoustic Emissions technique enlightened crucial aspects of the damage mechanisms activated, indicating simultaneous generation of both tensile- and shear-cracking modes, attributed to the layered structure of Dionysos marble.