Tire-induced surface stresses in flexible pavements

Site observations of flexible-pavement distress in various countries indicate frequent occurrence of longitudinal cracking in the top asphalt concrete layer. Analytic and numerical studies of multilayer elastic systems subject to wheel loads have linked longitudinal cracking to surface tensile stresses. However, due to the complexity of tire-pavement interaction resulting from tire geometry and loading conditions, accurate and fully representative distribution of surface stresses remains partly unknown. An attempt is made to provide information on surface stresses that derives from both theory and experiments. In particular, contact mechanics solutions are analyzed to gain information on loads that are subsequently used in performing numerical evaluation of surface stresses. Examples of three-dimensional computations using the finite-element code ABAQUS illustrate the analysis. The results indicate a greater potential for tensile stresses outside the tire treads than in the middle of the treads.