Integrated experimental-computational approach for three-stage creep characterization of asphalt mixtures under coupled high temperature-humidity loading

Abstract

Rutting in asphalt pavements remains a critical challenge for infrastructure resilience under climate extremes. However, the effects of stress levels on the creep behavior of asphalt mixtures subjected to high temperature-humidity conditions have not been fully explored, especially when three-stage deformation occurs. Therefore, this study firstly proposes a five-parameter nonlinear viscoelastic model to characterize the fully-stage of the creep behavior, followed by the identified model parameters via the differential evolution algorithm. Subsequently, a Grünwald-Letnikov fractional calculus-based operator splitting algorithm, implemented via a user-defined material subroutine, achieves computational efficiency while preserving nonlinear fidelity. Finally, the creep test was simulated based on the compiled user material subroutine and finite element modeling. The results indicate that the proposed model can effectively characterize the three-stage deformation characteristics of asphalt mixtures under high temperature-humidity conditions. The Instantaneous elastic modulus under moisture conditions decreased by 27% compared to dry conditions. The proposed finite element implementation algorithm can effectively simulate the creep behavior of asphalt mixtures under different loading and moisture conditions.