Analysis on fracture properties of concrete-epoxy interface

Sandwiched wedge splitting method and double-K fracture model were used to study the fracture properties of concrete-epoxy interface. Compared to the prototype specimens, the cracking load, ultimate load, double-K fracture parameters and fracture energy of the sandwiched specimens formed by epoxy injection improve, while the cohesive fracture toughness shows no improvement. To specimens with rough interface, the cohesive fracture toughness value calculated with soften curve is identical with that of the test. And the cohesive fracture toughness value of specimens with smooth interface is lower than that of specimens with rough interface because of the wall effect. It is assumed that the epoxy injection technique helps postpone the developing of cracks in sandwiched specimens, which improves the initial fracture toughness. The initial fracture toughness is used to judge interface crack deflection, and the results agree well with the tests. It is recommended that the initial fracture toughness be used to characterize the fracture properties of concrete-epoxy interface.