Research On The Asphalt Pavement Optimal Structure Combination Based On The Cracking Characteristics

At present, the asphalt pavement in China has a very common problem—early damage, especially the cracking problem. As we all know, once the crack comes into being, it will be expand rapidly and lead rain to enter the road, which will greatly shorten the life of the asphalt pavement.The formation of the crack in the asphalt pavement is related to many factors, such as environmental factors, construction factors and some anthropogenic factors. In the researches on the crack of the asphalt pavement at home and abroad, the vehicle load and the interfacial bonding conditions of the layers are not considered adequately. And there is still a lot of work that is worthy of being advanced further about the researches on the cracking features of the asphalt pavement’s structure, for example, the location that the cracks may first come into being and the influence of structure combination of the asphalt pavement on the cracking characteristics. This paper is based on the summary of what previous studies have achieved, combined with the actual situation of high grade asphalt pavement in our country. Considering the separation between the layers in certain friction conditions, it uses the finite element calculation model to analysis the stress characteristics of asphalt pavement structure of different combinations. Taking this as the foundation, it discusses the best structure combination, considering loads of the asphalt pavement.According to the results of this paper, some basic conclusions that can be obtained are as follows:(1) All the structural combinations that the study calculated has showed that the maximum tensile strain occurs only in the edge of the contact surface or inner the tire pavement, namely in or near the scope of the wheel track.(2) In the conventional thickness scope of the asphalt pavements, the change of the thickness has little effect on the change of the maximum tensile strain.(3)The fatigue crack caused by overload on the asphalt pavement may start from the bottom of the upper layer and the top of the bottom layer. The reasonable combination of top layer, surface layer and bottom layer modulus can abate the formation and development of the fatigue crack caused by the overload to a certain extent.(4) It proposed a reasonable range of the modulus ratio among the upper, middle and lower layer and the base layer in this paper. Selecting pavement materials within the scope and designing the structure of the asphalt pavement can effectively reduce the fatigue cracks generated, thereby improving the service life of the asphalt pavement.