RESEARCH ON VISCOELASTIC FATIGUE DAMAGE MODEL OF AGING ASPHALT MIXTURES

In order more practically to reflect the fatigue damage characteristics of the asphalt pavement during the course of service，from the basic characters of viscoelastic material, the dissipation functional is constructed based on the constitutive equation and the definition of dissipation energy. Taking definite dissipation energy as a damage variable, the viscoelastic fatigue damage model is established for aging asphalt mixture based on Burgers model. The viscoelastic parameters are identified through Direct Tensile Test. The damage function and damage evolution equation are calculated. The calculation theory and method of cumulative fatigue damage, which consider the aging effects to the fatigue damage, are proposed. It provides a basis for fatigue life predictions about the asphalt mixture under different aging degrees. The critical fatigue damage degree and fatigue life calculation formula are derived by employing the fatigue damage model, which are calculated and compared, the accuracy meets the requirements, which verifies the rationality of the viscoelastic fatigue damage model.