Heavy Load, Low Tire Pressure Rutting of Unbound Granular Pavements

Abstract

In a study of effects of wheels with very heavy loads but very low tire inflation pressures on unbound, single-layer granular pavements, trafficking tests were carried out on full-scale indoor pavements at the Pavement Test Facility, Transport Research Laboratory, Crowthorne, U.K. Two values of wheel load, two values of tire inflation pressure, and three subbase thicknesses were used. Testing was continued to 10,000 passes and a total of 4,704 measurements of rut depth made at intervals, providing a statistically significant data set. The development of ruts, the rut cross sections, and the effects of halving the tire inflation pressure or nearly doubling the wheel load are presented. Comparisons are made to a rut prediction equation derived by the U.S. Army Corps of Engineers Waterways Experiment Station in similar work, and conclusions are drawn.