Dynamic Analysis and Determination of Maximum Tensile Strain of Bottom Asphalt Concrete for Different Vehicle Velocities

Studying the stress, strain and deformation in pavement under traffic loads is one of the most important areas in pavement engineering. Tensile strain in the bottom of asphalt, leads to the most common type of failure (fatigue); therefore, it is an important parameter to be analyzed. In this study, the pavement structure has been analyzed and then for validation, the output in all elements and points were compared to the field results obtained from University of Pensylvania. The further studies were conducted by 3D program which indicated a good agreement with the results from field and the first finite element-based program. In static and quasi-static loadings, the maximum strain were observed exactly under the load center, while in dynamic loading, unexpectedly,themaximum value occurred behind the load center, and the distance increases by increase of vehicle velocity. This study includes the effect of load speed on tensile strain in asphalt sub-layer.