Research On Asphalt Pavement Surface Crack Under Traffic Load And Temperature

Asphalt Pavement Cracks is one of the main disease and a common phenomenon in asphalt pavement. The current study of asphalt pavement crack is to begin the bottom of the structural fatigue crack, or the reflection crack, the crack is from bottom to top. Currently people have a good understanding of this crack mechanism and preventing measures have also achieved a great success.Traditional asphalt pavement design theory uses the admissible bending stress as design indicators to control the construction layer fatigue crack. However, this theory does not apply asphalt pavement surface crack. There are not design indicators to control this crack in Asphalt Pavement Design Specifications. This surface crack mechanism is not clear. The present study on the mechanism of such crack mainly focuses on the vehicle overloading and non-uniformity of tire pressure. There are few literatures about horizontal loads and temperature loads when temperature decreasing suddenly. The research on crack extension is also focused on vertical load. For horizontal load and temperature load, the literatures on crack extension are also few.The main cause of the asphalt pavement crack has two aspects of traffic load and the environment. In the traffic load, it is not complete to consider the vertical load only, but the horizontal load is neglect, and the temperature load is also an important factor. The paper firstly, based on linear elasticity theory, heat transfer theory and finite element method, establish the three-dimensional model of asphalt pavement structure, analyzes the mechanical response to asphalt pavement of vertical load, horizontal load, temperature load and their coupled, studies the mechanism of asphalt pavement surface crack. Then the paper builds two-dimensional model of asphalt pavement crack, based on the linear elastic fracture mechanics, heat transfer and finite element theory, analyzes the influence of vertical load, horizontal load, temperature load and their coupled to the stress intensity factors of crack.The results show the main cause of the asphalt pavement crack is that asphalt surface maximum tensile stress and the maximum shear stress is greater than the tensile strength and shear strength of asphalt mixture under horizontal load together with the vertical load. One factor of the surface crack is the temperature load that is caused by temperature decreasing suddenly in hot reason. For asphalt pavement crack extension, the horizontal load is the chief reason, the role of vertical load is smaller, and the temperature load is the smallest. The paper gives a good understanding of the mechanism of the asphalt pavement surface cracking, and provides a theoretical premise to prevent crack.