Non Destructive Damage Estimation on Rocks with Laboratory Measurements of Dielectric

Non–destructive testing methods constitute a fast growing field of study that concerns various materials. In addition to the up today bibliography a novel technique is presented here. It deals with the use of Dielectric Spectroscopy (DS) or Impedance Spectroscopy (IS) techniques for the verification of mechanical damages introduced in geomaterial structures. The main merit is that these techniques do not influence the materials structure or properties, thus it can be tested with several other methods. In this work damages are introduced in a geomaterial by uniaxial stress application while temperature is constant. Specifically, the damage caused to marble samples and its influence on the dielectric loss angle were measured and examined with respect to the externally applied uniaxial stress. Results indicate that when the applied stress is capable of leading to microcrack generation then tanδ values increase while for high values of stress, a loss peak is evident in the studied frequency range.