Evaluation of Near-Surface Stress States in Asphalt Concrete Pavement

A sophisticated three-dimensional (3-D) tire model was placed directly on a three-layer asphalt concrete (AC) pavement system to form a 3-D tire–pavement contact model. The model was then verified with measured contact stresses and was used to investigate near-surface stress states in the AC layer. When compared with the traditional uniform vertical loading model, the 3-D tire–pavement contact model produced stress states not only higher in magnitude but also more variable in distribution. The 3-D tire–pavement contact model produced much higher principal tensile stress and maximum shear stress near the tire edge; the increased stress was a possible explanation for instability rutting and associated top-down cracking. A critical shear plane was developed for the top 50 mm of the AC layer by using a p-q diagram, and the tire–pavement contact model produced a much higher shear yield percentage.