عنوان مقاله [English]
Therefore, the effect of the freeze-thaw process on the physical and mechanical properties of materials should be taken into account in areas with the risk of this process. In this study, the effect of freezing-thawing process on the mode I and mode II fracture toughness and the strength parameters of travertine have been investigated. For this purpose, to investigate the effect of freeze-thaw process on the mode I and mode II fracture toughness, the specimens were affected by 0, 1, 4, 8, 16, 32 and 64 freeze-thaw cycles and the fracture toughness of the specimens using cracked chevron notched Brazilian disc was determined. To investigate the effect of freeze-thaw on the strength parameters of travertine, the samples were subjected to confining pressure of 0, 2.5 and 5 MPa. Also, microscopic studies were performed to more accurately evaluate and evaluate the structural changes of the samples due to the application of freeze-thaw cycles and their texture changes. The results show that with increasing the number of freeze-thaw cycles, the mode I and mode II fracture toughness decreases exponentially and also, cohesion and internal friction angle decrease. And microscopic studies show that the microcracks in the rock have expanded due to freeze-thaw and new cracks have formed.