THE SHEAR STRENGTH AND MODE II FRACTURE TOUGHNESS OF LAYERED CONCRETE

The bond characteristics of layered concrete was studied by direct shear tests and double-edge notched single-edge compressing tests (DNSCT) to obtain the parameters of shear strength and mode Ⅱ fracture toughness. The influence of the pouring interval of two layers on the bond characteristics was researched. A linear relation between the cohesive and the mode Ⅱ fracture toughness was found, while there is no remarkable relation between the friction coefficient and the mode Ⅱ fracture toughness. According to the definition of the mode Ⅱ fracture, Mohr-Coulomb criterion was used to judge the mode Ⅱ fracture. A linear relation between the cohesive and the mode Ⅱ fracture toughness was derived theoretically. The mode Ⅱ fracture toughness could be estimated based on the cohesive strength so that the mode Ⅱ fracture tests which are complex and uncontrollable could be avoided. This research can provide referable parameters for the fracture mechanics study of layered concrete.