混凝土环氧树脂黏结界面的断裂性能分析

采用夹心楔入劈拉试件并结合双K断裂模型研究混凝土-环氧树脂黏结界面断裂性能.相比于原混凝土试件,环氧树脂注胶后形成的夹心试件的起裂荷载、极限荷载、双K断裂参数以及断裂能均有增长,而黏聚断裂韧度值没有提高;粗糙界面试件的黏聚断裂韧度试验值与采用软化曲线计算得到的黏聚断裂韧度计算值相等,光滑界面试件由于壁效应的存在,黏聚断裂韧度较低.可以认为环氧树脂注胶技术推迟了裂缝的再开展,使得起裂断裂韧度提高,采用起裂断裂韧度代入裂缝偏折判断条件进行界面裂缝偏折判断时,结果与试验相符.

Analysis on Fracture Properties of ConcreteEpoxy 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..