Study Of Asphalt Pavement Structure Resisting Rutting

In recent years, with the warming of the global climate and the increasing of the heavy traffic, the rut of the highway asphalt pavement in our country is becoming more and more serious, and most of which is flowing one. As a result, it is the main early damage phenomenon nowadays. The forming reasons of rut are complicated, which concludes both material one and the structure one. In past, we prefer to study the material ingredient, such as using the technology of SMA, SBS and Superpave in pavement construction. But the new survey shows that the rut in the upper layer and the middle layer is replaced by the rut in the middle layer and lower layer. Besides, although the appearance of rut is slight alleviating, it could hardly avoid larger rut.In the paper, with the early damage tacking detection and the experiments of the rut in the recent ten years, using the finite-element analysis method, we analyze mechanism of rut in pavement structure and find that in the new traffic and the climate condition the ingredient of pavement structure would seriously influence the pavement rut. But the constructed highways in our country are nearly all the semi-rigid base asphalt pavement structure which is unsuitable with the new situation.Breaking the traditional regular thinking tendency, we should study the influence of pavement structure ingredients to the rut through the new view and idea. Using the effective structure measures to improve the rutting resistance performance is the main research purpose of this paper. Practice is the only test of truth, the research based on the induction analysis about the pavement structure would have an important influence.Based on the drilling experiment and the shear theory analysis, there is a high value region of equivalent compressive stress, shear stress and shear strain between the 3 cm and 11 cm in the semi-rigid asphalt pavement. Besides, the flowing rut is controlled by the shear strain and we could improve the high-temperature modulus of middle layer of asphalt pavement to effectively reduce the shear strain and resist the rut. According to the layer design theory of asphalt mix, we study the high modulus asphalt concrete. According to the visco-elastic theory, we use dynamic modulus as the criteria and set the definition of high modulus asphalt concrete, and this method could effectively improve the high temperature dynamic modulus of middle layer without lowering the performance of normal and low temperature, which lay a foundation for the application of high modulus asphalt mix.Since there are structure faults in the semi-rigid base, we put forward the design theory of pavement structure combination design principle and binder course design theory. In other words, we put a layer of asphalt stabilized crush stone or the graded crushed stones between the asphalt layer and the semi-rigid base in order to improve the working condition of semi-rigid base layer and coordinate the deformation of the whole pavement. Through the above methods, we could reduce the rut and crack of the pavement, which is suitable with long-life asphalt pavement theory, and which is different from traditional binder course.According to the requirement of binder course design theory and the material performance, we research the material performance and construction technology of binder course. And we put forward the matching technology including the mix design method, gradation range,the technical requirement and the construction control point, which is validated by the construction. Besides, the proposed design modulus is realized through the construction practice, and it provides a technical support for the design and application of binder course.Both the construction application and the economy analysis show that we could coordinate the deformation of pavement and reduce the rut through improving high-temperature dynamic modulus of middle layer and the measures of binder course combined pavement structure. What's more, the binder course combined pavement structure in the heavy traffic highway is still performing a good rutting resistance 5 years after opening. The rut depth is smaller or equal to the semi-rigid asphalt pavement, and there is no damage such as cracks etc, which is apparently better than the semi-rigid one. Furthermore, this kind of road structure also has a good economic index.