A Research On Damage Model Of Interaction Between Fatigue And Creep Of Asphalt Mixture

Fatigue cracking is the main distress of asphalt pavement, so the fatigue performan- ce of asphalt mixture is major control index in many countries'pavement design methods. As asphalt mixture is viscoelastic material, the influence of temperature for the viscoelastic damage evolution could not be denoted by the traditional phenomenology method. And, fatigue mechanism of asphalt mixture can not be revealed.This dissertation is supported by National Natural Science Foundation—"The uni- fy fatigue damage model of asphalt mixture and its application",then the fatigue performance of asphalt mixture is studied. First, fatigue failure of asphalt pavement is caused by the interaction between fatigue-creep damage. Based on strain equivalence hypothesis , complex modulus was used to define the damage variable when two different damage interact. By using fatigue-creep damage theory, the model of damage evolution and the prediction model of fatigue life are built, which could reflect the influence of interaction between fatigue-creep damage. By thermodynamic and physical mechanics analyzing the model of damage evolution, results show that model satisfy thermodynamic laws and physical requirement,which verifies the rationality of the proposed theory.Then, dynamic creep experiment for AC-13, AC-20 asphalt mixture is carried on. The parameter of the mechanism model of strain and number of repeated loading is got by using data of creep experiment. Then the viscoelastic parameter of fatigue life prediction model is also acquired.Third, through analyzing the damage evolution of asphalt mixture, new fatigue failure criteria was established by defining the damage rate. Then, fatigue experiment for AC-13, AC-20 asphalt mixture is carried on The parameter z of damage evolution model are obtained by analyzing fatigue test data.Finally, the prediction model of fatigue life of asphalt mixture is built by using above parameters. The model is well fitted, which proved fatigue failure of asphalt mixture is caused by interaction between fatigue-creep damage under different fatigue tests.