Mechanistic Rutting Prediction Using a Two-Stage Viscoelastic-Viscoplastic Damage Constitutive Model of Asphalt Mixtures

A two-stage viscoelastic-viscoplastic damage constitutive model and the corresponding parameters calibration method were briefly given. Then, the numerical algorithms of the proposed constitutive model were implemented based on a radial return mapping algorithm and realized using the user material subroutine in the well-known finite-element code. A rutting prediction method of asphalt pavement was proposed based on the two-stage viscoelastic-viscoplastic damage constitutive model along with a loading equivalence method. Laboratory wheel tracking tests under different temperatures, different loading levels, once variable amplitude loads, and step variable amplitude loads were conducted to evaluate the efficiency of rutting prediction. Finally, the test results were compared with finite-element simulated results. All the results indicate that the constitutive model and the corresponding rutting prediction method proposed in this paper can effectively represent the rutting developing rules under standard loading and complicated variable amplitude loading with reliable prediction accuracy. Meanwhile, the mechanism of rutting development can be characterized through analyzing the evolution rules of internal state variables based on the proposed constitutive model.