Characterizing non-linear fatigue crack growth and size effect in plain concrete beams with a hybrid effective crack and cohesive zone model

Abstract

The mechanical response of concrete is largely influenced by the interlocking coarse aggregate, which supplies the cement matrix with a resisting cohesive crack bridging force. Under low and high cycle fatigue loading, the cohesive stresses can influence the crack growth rate and the structural load capacity. A new method used to quantify the cyclic cohesive zone properties and effective crack resistance in three point bending single edge notch plain concrete specimens of different sizes under both low and high cycle fatigue loading is presented here. For validation, three point bend concrete specimens of two different sizes were tested under crack mouth opening displacement controlled low cycle quasi-static loading and force controlled high cycle fatigue using constant, variable, and random amplitude loading sequences. The results indicate that the cohesive stress-dependent cyclic crack resistance can be quantified and used to effectively characterize the high cycle fatigue non-linear crack growth and size effect.