Creep behavior of hot-mix asphalt due to heavy vehicular tire loading

The objective of this study is to characterize the creep behavior of hot-mix asphalt (HMA) at intermediate (20°C) and at high temperatures (40°C). To accomplish this objective, a nonlinear time-hardening creep model, characterized through laboratory testing, was incorporated into a three-dimensional (3D) finite-element (FE) model, which was used to calculate permanent creep strains after applying repetitive vehicular loading cycles at the pavement surface. Two different tire configurations were simulated representing a typical dual-tire assembly and a newly introduced wide-base tire (dual-tire: 275/80R22.5 and wide-base tire: 455/55R22.5). Results of the 3D FE model were successfully verified against pavement response measurements in the field at the Virginia Smart Road. While the elastic or linear viscoelastic FE model may not simulate permanent deformation or shear creep strains after repetitions of vehicular loading, a nonlinear time-hardening creep model could predict primary rutting damage in HMA and shear creep strains at the edge of the tire imprint caused by different tire configurations.