The Effect of Slope Geometry and Shoulder on Rutting Depth of Flexible Pavement

The slope and width of the road shoulder are important parameters in geometry of the road pavement. Therefore, it is important to comply with the requirements relating to the slope and width of the shoulders. So that by using the minimum width and slope of the shoulders according to regulations not only stresses and strains transferred to the lower layers will decrease, but also reduces damages in asphalt layers, base, and sub-base. Therefore, it is vital to conduct analyses which can bring good amount of accuracy in assessment of the stress and settlement due to shoulder width and slope. The aim of this study is to investigate the effect of geometry of the shoulder on the performance and behavior of weak or strong pavement. For this purpose, numerical two-dimensional modeling of the road pavement (asphalt base sub-base) on which the axel load is placed was done using finite element method, ABAQUS, and the effect of the shoulder width and slope on the stresses and settlements caused by the strong and weak pavement have been studied. Also for verification of the software, several obtained field values are compared to each other. The results indicate that the increase in the width of the shoulders and the decrease in the slope will cause in decrease of the stress and settlements in different layers of the roadways. Thus, creating less steeper shoulder and wider pavement can reduce damages and will contribute to the increased safety and sustained life of the pavement.