Research On Axle Exchange And Design Parameter Of Asphalt Pavement Based On Measured Axial Load Spectrum

Along with the rapid development of the highway, the characteristics of traffic flow have changed a lot. The appearances of heavy axle load, big flow and channelized traffic for asphalt pavement have brought serious test, which have caused widespread damage of pavement. According to the asphalt pavement structure damage phenomenon, the researchers often take measures just from the materials design and quality control of road, and no serious reflection of the design method of asphalt pavement structure has been taken.This paper summarized earnestly the classic method of asphalt pavement structure design method in and abroad, design indexes and parameters in the current standard of asphalt pavement design have been discussed, and correlative suggestions have been puted forward. The size and the number of axle load action is the two main parameters of structure design, typical axial load spectrum of each section has been obtained on the base of analysis of measured axial load data in zhejiang area. Results also indicate that each expressway is in different degree of overload, the scope of axle load distribution is wide, the number of heavy vehicles on hang-jin-qu road is the largest. According to the principle of vehicle construction, combined with the characteristics that the number of heavy-duty vehicle in traffic flow is large, the empirical formulas of wheel pressure, tire grounding area and axle load in the design method of Belgium is modified, and a empirical formulas is put forward which is suitable to China's situation. Combining the present domestic common pavement structure forms, and considering the differences over pavement materials performance comprehensive identified 11 kinds of pavement structure, with a combination of 306 elasticity, finite element analysis are discussed based on the deflection, flexural-tensile stress of structure and surface compressive strain of road bed. At last, axle load conversion relationship was put forward based on the deflection equivalent, flexural-tensile stress equivalent and surface compressive strain equivalent. In order to consider the affection of pavement roughness on pavement structure, the friendship between index IRI and PSD index was discussed, according to the technical standard of asphalt pavement maintenance about the RQI related regulations, critical dynamic load coefficient was recommend respectively.