RESEARCH ON FATIGUE DAMAGE OF CONCRETE UNDER UNIAXIAL COMPRESSION ON THE BASIS OF TOUGHNESS

Based on the analysis of main influencing factors of concrete fatigue life under uniaxial compression, it is proposed that the static toughness of the concrete can be used to evaluate its fatigue life. A proper index is proposed to calculate the static toughness, and meanwhile the relationship between static toughness and fatigue toughness is established according to the theoretic analysis. Then, a new mathematical toughness dissipation model expressed with static toughness is established. On the basis of the model, and the fatigue toughness dissipation as a damage variable, a fatigue damage evolution equation of concrete under compression is derived, and a three-stage damage evolution law is demonstrated from the results. It is verified that the damage evolution law expressed with static toughness correspond well with the damage evolution law expressed with the fatigue toughness measured from the fatigue test.