Impact quantification of wide-base tire loading on secondary road flexible pavements

There is a need to evaluate the damage caused by the new generation of wide-base tires on low-volume secondary roads because of their increased use on trucks. In this study, a three-dimensional (3D) finite-element (FE) model was built to simulate the realistic tire loading on secondary road pavements. The model allows for predicting pavement responses to loading applied by various tire configurations. In addition, the model incorporates the measured 3D tire-pavement contact stresses, models hot-mix asphalt (HMA) as linear viscoelastic material, simulates continuous moving load, and utilizes implicit dynamic analysis. The analyzed pavement structures comprised a 76-mm HMA layer and an aggregate base layer with various thicknesses (203, 305, and 457 mm). The impact of a wide-base tire on secondary road pavement damage was analyzed using available damage models and was compared to that resulting from conventional dual-tire assemblies. It was found that the new wide-base tire (455/55R22.5) caused greater fatigue damage, subgrade rutting, and HMA rutting (densification) but less HMA rutting (shear) and base shear failure compared to the conventional dual-tire assembly when carrying the same load. The findings indicate that wide-base tires' impact on secondary road pavements depends on the roads' predominant failure mechanisms. Hence, calculated combined damage ratios can be used for road usage pricing and pavement design practice when wide-base tires are used.