Rheological Properties of Hot-Mix Asphalt during the Compaction Process Based on the Bodner–Partom Model

Abstract

The traditional viscoelastic-plastic constitutive model of asphalt mixture is mostly suitable for the case of small deformation at room temperature, which may have difficulties in the evaluation of the large plastic deformation during the compaction process. In order to evaluate the viscoelastic-plastic rheological characteristics of hot-mix asphalt (HMA) during construction compaction, in this research, the Bodner–Partom (BP) model was revised by considering the strain after the total strain minus the instantaneous elastic strain, and the viscoelastic rheological parameters of the revised BP model were obtained through uniaxial compression creep tests. Also, the creep behavior of the BP model was verified through numerical simulation of the finite-element method. The results found that in the initial creep stage, with the increase of initial compaction density, the instantaneous deformation decreased, and the deformation recovery rate increased after unloading. Correspondingly, the pure viscosity parameter (η) increased, the hardening constant of the load (Z) increased, and the limit value (D0) decreased, indicating that the viscous properties of HMA were enhanced, and the plastic and viscoplastic strain rates decreased. In the stable creep stage, the strain value was the largest under the initial loading. As the number of cycles increased, the HMA strain rate decreased and tended to be stable, and the compaction was basically formed. Correspondingly, η gradually increased, Z increased, and the plastic and viscoplastic strain rates decreased. D0 decreased first and then tended to be stable, indicating that the proportion of plastic deformation of single cycle load to total deformation gradually decreased and tended to be stable. With the increase of initial compaction density, the plastic strain of the same loading cycle decreased first and then tended to be consistent. Finally, it was found that the simulated calculation curve further verified the rationality of the BP model. The relevant results can lay a theoretical foundation for analyzing the rheological mechanical properties of HMA in the construction stage.