Charge Transport Phenomena In Rock Products Subjected To Stress Up To Fracture

This work studies the variations of the electric current caused by the application of an electric field on marble samples when they are subjected to continuously increasing mechanical stress at a constant rate up to fracture. The external electric field is applied in a direction perpendicular to the applied mechanical stress. An increase of the level of the electric current was observed when micro-damages started to occur in the samples. The increase of the electric current was approximately 14%. Consequently, the current started to decay abruptly and the sample failed. This electric current recording is compared with the corresponding electric recording without applying the external electric field (Pressure Stimulated Current technique). Both recordings show similar qualitative characteristics. The most obvious of these characteristics are that the electric current starts to develop when microcrack structures start to form due to the externally applied stress. Both recordings show a maximum in the vicinity of fracture.