ABSTRACT
The fatigue problem of quasi-brittle material like concrete has long been studied, but most research approaches are purely phenomenological without inquiring the fatigue mechanism. In this paper a three-dimensional model is proposed to describe the fatigue behavior of concrete within the framework of continuum damage mechanics. The fatigue damage evolution is based on elastic damage energy release rate. Specifically, a mechanism of damage healing and driving competition is introduced to explain the typical concrete fatigue phenomena, upon which an analytical model of damage evolution is formed. The loadingunloading irreversibility concept is adopted to obtain the development of the damage parameter even inside the damage yield surface in fatigue loading case. A set of numerical examples are presented, the validity and reliability of this model is assessed through comparisons with experimental results in literatures.
