Full-depth pavement responses under various tire configurations: Accelerated pavement testing and finite element modeling

A challenge associated with the use of wide-base tires is the accurate quantification of pavement damage induced by these tires. In this study, an accelerated pavement testing program was performed to compare the strain responses of full-depth pavement caused by conventional dual-tire assembly, the first generation of wide-base tires, and the new generation of wide-base tires. Results of the experimental program indicate that the new generation of wide-base tire (455/50R22.5) causes less fatigue damage potential than the first generation of wide-base tire (425/60R22.5). Considering the significant effect of tire-pavement interaction on pavement damage quantification caused by various tire configurations, a three-dimensional (3-D) finite element (FE) model was developed using the measured 3-D tire contact stress distribution. The FE model incorporates linear viscoelasticity of hot-mix asphalt (HMA) and continuous moving load using implicit dynamic analysis. After the model was validated against field strain measurements, the calculated octahedral shear stresses were used to compare the surface cracking and HMA rutting potential under various tire configurations. Results showed that the wide-base 455 tire causes less octahedral shear stress at the upper part of the HMA layer than dual-tire assembly, probably due to the more uniform vertical contact stress distribution and lower transverse tangential stresses. However, the wide-base 455 tire causes greater responses at deeper pavement depth, including tensile strain at the bottom of HMA and compressive strain at the top of subgrade. These response differences diminish as pavement thickness increases. In addition, the relative fatigue damage potential caused by the wide-base tire in thin pavements could be reduced when considering the wandering effect and possible pressure differential in dual-tire assembly.