Mechanistic Comparison of Wide-Base Single versus Standard Dual Tire Configurations

Abstract

Wide-base tires are gaining renewed interest in the U.S. trucking industry as tire and rim technology and design continue to improve. First introduced in the early 1980s and termed “super-singles,” new generation, wide-base tires have been developed to allow for lower inflation pressures and larger contact areas than their predecessors. Single tires are of interest to freight haulers because with fewer tires and lighter rims, cargo capacity can increase. Early theoretical and physical modeling studies of super-singles largely found them to be more damaging to highway pavement structures than standard dual tire configurations. However, in light of new tire advancements, the impact on pavement response and performance of the wide-base configuration should be reevaluated. In addition, the accuracy of theoretical models in predicting pavement response under the new wide-base tires should be evaluated because models are often used by agencies to determine single-tire weight limits and permitting. A conventional dual tire assembly (275/80R22.5) was evaluated versus a newly developed single wide-base tire (445/50R22.5) at the National Center for Asphalt Technology Test Track. Embedded asphalt strain gauges and earth pressure cells allowed for direct pavement response measurements and comparisons between the two configurations. In addition, theoretical modeling using layered elastic theory was used to evaluate both configurations. The pavement response measurements indicated no statistical difference between the two configurations. The theoretical model tended to overpredict the response under the wide-base configuration. Future studies should attempt to model the tire-pavement contact area precisely to improve accuracy under the wide-base tire.