Pavement Response to Dual Tires and New Wide-Base Tires at Same Tire Pressure

Abstract

Although concern was raised about the introduction of radial tires due to their higher inflation pressure compared with that of bias tires, radial tires have been proven to reduce the strain at the bottom of the hot-mix asphalt (HMA) layer. However, conventional wide-base single tires have been shown to be more damaging to pavement than dual tires. The damage mainly depends on the tire tread width and inflation pressure. It has been suggested that wide-base tires may produce damage equivalent to that of dual tires if the maximum load per tire is limited to 11.6 kg/mm of tire tread width. Recent advances in tire design and material have led to the design of a new wide-base tire that is wider and flatter in the crown area to provide a uniform contact stress distribution. It operates at an inflation pressure of 690 kPa for 151-kN tandem axle load. An experimental program studied the effects of the newly developed wide-base tire on a flexible pavement section at the Virginia Smart Road under different loading and environmental conditions. Testing results have shown that the newly developed wide-base tires induce approximately the same horizontal tensile strains under the HMA layer as do equivalent dual tires. Hence, the fatigue damage expected from these newly developed wide-base tires is the same as that produced by dual tires. However, the vertical compressive stresses induced by the wide-base tire are greater on the upper HMA layers of the pavement. The difference in stresses diminishes with depth and becomes negligible at the bottom of the subbase layer.