Characterization of fatigue failure mechanism for concrete airport pavement

The stress field of the airport pavement is biaxial. The different signs of the principal stresses form a biaxial Compression-Tension stress region (C-T region). The current research is to characterize the material properties of concrete in the biaxial c-C-T region, where the principal compressive stress is larger in magnitude than the principal tensile stress. The motivation of this research is to correlate the static behavior and fatigue behavior of concrete in the biaxial c-C-T stress region. From the previous research in the t-C-T stress region, where the principal tensile stress is larger, it was found that the failure of concrete under both static and fatigue load was governed by crack propagation. A fracture-based fatigue failure criterion was proposed in the t-C-T region, wherein the fatigue failure can be predicted using the critical Mode I stress intensity factor (SIF). In the current research in the c-C-T region, two failure modes were found. One was inelastic displacement based compressive failure mode, which was explained by the band-damage zone model, and the other was crack length based tensile failure mode, which was explained by the previous fracture model proposed in t-C-T region.