LAUSR

The fatigue damage of concrete is an important reason for cracking and failure. To comprehensively study fatigue behaviors of concrete under uniaxial compression, cylindrical specimens with two different strength levels were made for cyclic loading tests. The evolution of fatigue process was detected via sensors, strain gages, and an X-ray computed tomography (CT) scanner. Parameters of fatigue life, deformation, internal cracks, and strength under different stress levels are analyzed based on measurements. The stress-cyclic number (S-N) equation is also given. Then, the fatigue damage parameter D is used to evaluate the status of damage. Additionally, a finite element modeling approach is developed based on the CT images to simulate the evolution of fatigue cracks within concrete specimens. With results of both macroscopic and microscopic analysis, the fatigue failure mechanism of concrete is expounded. The analysis results of this paper can provide a basis for the safety assessment for concrete structures.