Fatigue of concrete

Fatigue of concrete is related to development of micro-cracks inside concrete as a result of cyclic loading on concrete elements. This leads to macroscopic behavior like permanent reduction in stiffness and increase in strain with each cycle, which then can be defined as the fatigue process in concrete. The evolution of these mechanical properties (strain and modulus of elasticity/stiffness) with each cycle (and time) takes place in three stages, in first stage, degradation rate is high but decreasing, second stage, this rate is stable and constant; third stage degradation grows very quickly until failure is reached.