Analysis of Structural Behavior of Asphalt Pavement with Small Radius Turning

Abstract

To clarify the structural response of small radius turning sections of asphalt pavement, the effect of vertical and torsional loads was comprehensively considered for the structural response calculation of small radius turning section based on layered elastic theory. Firstly, the structural response obtained by layered elastic theory were compared with the results calculated by finite element method (FEM). Secondly, the maximum shear stress of the small radius turning section under vertical and torsional loads and under single vertical load were compared. Thirdly, the influence of interlayer contact state on the response of pavement was analyzed. Finally, the response of small radius turning section pavement structure was explored as the tire-road contact area continuously decreased. The results showed that: (1) the shear stress trend of the surface layer bottom obtained based on FEM by coupling a torque on a vertical load was consistent with that by analytical solution based on layered elastic theory, but the maximum value was about 2.8 times larger than that of analytical solution. (2) When the torsional distributed and vertical loads acted on the pavement surface simultaneously, the area with larger maximum shear stress of the pavement structure layer continuously shifted upward compared to the single vertical load condition, and the value of the largest maximum shear stress is about 4 times than that of the single vertical load condition. Therefore, when designing pavement for small radius turning sections, torsional load should be taken into consideration. (3) As the contact state between the base layer and bottom layer of pavement (cement stabilized macadam and the lower AC-20 layer) deteriorated, the maximum shear stress of the AC20 layer continued to increase, and the closer it was to the center of the tire, the greater the increase in maximum shear stress. In addition, the deeper the pavement, the greater the influence of interlayer contact state on the maximum shear stress. (4) The continuous reduction of tire-road contact area led to an increase in pavement surface maximum shear stress, and the closer to the pavement surface or the center of the tire, the greater the increase in maximum shear stress.

Keywords: Small radius turning section, Layered elastic theory, Structural response, Asphalt pavement, Maximum shear stress