The Effects Non-uniform Contact Pressure Distribution Has on Surface Distress of Flexible Pavements Using a Finite Element Method

Abstract

The current practice in pavement design is to use a circular uniformly distributed load as the input to ascertain the maximum stresses in the pavement. This is not the reality; tyre-pavement contact stress distributions are very complex. The distress on the surface of the pavement in the form of rutting and surface initiated cracking is very much dependent on these complex stresses. This study investigates the effects that non-uniform contact pressure distributions have in comparison to the traditional circular loading on the initiation and rate of accumulation of this distress. The problem has been modelled using the CAPA-3D finite element software. The traditional circular load was modelled for two different asphalt materials with different moduli. The stresses in a number of key locations were recorded and measured. Then the non-uniform loading was modelled using the same procedure. What was of particular interest was the difference in the peak surface stresses and positions between the two different methods of loading. The non-uniform loading created significantly larger stresses on the surface in comparison to the circular loading. The non-uniform loading also created significant shearing forces close to the surface. This leads to a greater propensity for the surface to develop rutting and cracking to develop at the surface. The differences started to become less evident with depth and/or distance from the loading area for the principal stresses. It is recommended that for the design of surface layers non-uniform contact pressures should be used.KeywordsPrincipal StressContact PressureAsphalt PavementInflation PressureContact PatchThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.