Full-Depth Flexible Pavement Response to Different Truck Tire Loadings

The objective of this paper is to investigate the potential indication of distress in medium-volume, full-depth flexible pavement when exposed to loading conditions under accelerated pavement testing at various speeds, inflation pressures, and loads, under three different tire configurations: dual-tire (11R22.5), and old and new generations of wide-base tires (425/65R22.5 and 455/55R22.5), respectively. In addition to longitudinal strain measurements at the bottom of hot-mix asphalt, a three-dimensional finite element model was developed in order to evaluate pavement response to loading at various critical locations in the pavement after being calibrated with field-measured data. Field measurements showed that the new generation of wide-base tires, 455/55R22.5, yields 7% more longitudinal strain than a dual-tire assembly at the same tire pressure. The dual-tire assembly shows differential longitudinal strains of 13 to 66% if the very common difference in inflation pressure between the two tires in the dual-tire assembly ranged from 140 and 555kPa, respectively. Using calculated parameters indicative of pavement distresses, the study found that for medium-volume, full-depth flexible pavement under the same loading and environmental conditions, the 455 wide-base tire has the potential to cause similar secondary rutting and fatigue cracking as the dual-tire assembly. In addition, less potential for primary rutting and significantly less potential for top-down cracking are expected when a wide-base tire is used.