Analysis On Asphalt Pavement Axle Load Conversion Under The Condition Of Heavy Axial Load

The demand of transportation enhanced day by day because of the rapidly expand of economy of our country in recent years. Meanwhile, huge change occurs in the road traffic condition, the volume of traffic on the first-class highway is generally big. The quantity of heavy vehicle has grows quickly, moreover the carrying capacity of vehicles increases, the axle load quality to be also getting bigger and bigger as well as the universal vehicles overload, the Channels of vehicle, causes the asphalt pavement to intensify rapidly under the heavy load transportation function damage question. This situation put forward new requirements for the design of asphalt pavement on the axle load conversion process.In this paper, for the heavy axle load traffic conditions, we investigate the performance of asphalt pavement in heavy axle load traffic conditions, and analysis the usual damage of asphalt pavement under heavy axle load traffic conditions. By the finite element analysis software ABAQUS, we quantitative analysis the influence of deflection, bottom stress of heavy layer and compressive strain on top of subgrade on asphalt pavement, and thus demonstrated the devastating effects of asphalt pavement under the heavy traffic. According to the principles of axial-load conversion based on deflection equivalent, tensile stress as well as compressive strain of foundation, different types of asphalt pavement had been selected to research the axle load conversion of semi-rigid asphalt pavement, combined asphalt pavement and flexible asphalt pavement respectively.By analyzing a number of causes of usual damage for asphalt pavement, and through the investigation of performance of pavement, analysis drawn the damage caused by heavy traffic on asphalt pavement is one of the main factors. Based on this, we analysis some of the load icon at home and abroad, and to determine the icon used in this paper is I load icon, and drew on the axle load and the ground area of Belgium, the calculation reveals the ground area and ground pressure of different axis conditions, and then by the finite element analysis software ABAQUS, simulate the mechanical response of asphalt pavement at all levels of axle loads, and thus quantitative analysis the deflection, stress and other effects of asphalt road surface on heavy axle load conditions, once again shows the necessary of axial-load conversion on the heavy axle load conditions.Finally, it calculates the axle load conversion coefficient of different levels of load conditions for different form of pavement. For semi-rigid asphalt pavement, modular and flexible layer of asphalt pavement in accordance with the axle load based on bottom stress principle, the axle load conversion coefficient obtained is relatively close to about 0.986, the n value is 8.96, and it consistent with the recommendation of heavy axle load index value of 9 in specification. In accordance with the principle of deflection based on axle for three different types of pavement structures are quite different, the semi-rigid asphalt pavement is 0.9666, n value of 4.83, combined asphalt pavement is 0.9437, n value of 4.82, while the flexible base pavement is 0.9195, n value of 4.6. The three different types of pavement structures are relatively close to the conversion factor, which is about 1, n=5, in accordance with principle of axle load based on compressive strain of the top subgrade.