Evaluation of the Effect of Tire Loads with Different Contact Stress Patterns on Asphalt Rutting

Road pavements are constructed to carry traffic which applies its load to the pavement through the contact area between the tire and the pavement surface. Previously, the tire-pavement contact area and stresses were idealized, as appropriate instruments for quantification of these contact stresses were not available. The Stress-In-Motion (SIM) technology has made it possible to characterize these contact stresses at low speeds. In a recent Heavy Vehicle Simulator (HVS) test on various layers of Hot Mix Asphalt (HMA), the effects of non-uniform tire-pavement contact stresses were directly measured through application of two distinct types of tire-pavement contact stresses onto the HMA pavement. The rutting response of the pavement specifically showed the direct effects of these non-uniform contact stresses. In this paper the background to the tire-pavement contact stresses is discussed briefly, followed by details regarding the specific rut responses of five HVS tests where the pavement performance reflected the effects of the non-uniform tire loading conditions. Analysis of this data is presented together with discussions on the potential effects of this information on roads carrying real traffic and their rut development.