The Study Of Selecting Maintenance Program And Asphalt Overlay Design Of Highway Asphalt Pavements

The expresway constrution in our country is deueloping vigorousty, expressway as the most important portion of the highway networks has taken shape. In accordance with the highway construction rule, when highway construction scale to a certain extent, maintenance and management will become the emphases of road management department, while pavement maintenance program, will become an important aspect.Because of the importance of road survey, this paper first identified the investigation contents of highway asphalt pavement, and baseing on the contents, investigated the road conditions in detail, and then analyzes the main types of diseases in the road and the causes of the disease, the analysis lay a foundation for selecting pavement maintenance alternatives and overlay design research; Combined with pavement performance survey data, the two kinds of domestic and foreign common asphalt pavement performance evaluation method is analyzed, and the problems of the two methods are pointed out, and the maintenance decision index is put forward for pavement; According to the actual situation of pavement maintenance and a maintenance method can repair many diseases of pavement and the maintenance of the same way can merger pavement different diseases, the concepts of deep repair rate, middle repair rate, skin repair rate are proposed, then choose maintenance alternatives according to the concept that if a pavement need too much maintenance, it needs a rehabilitation or reconstruction, if a pavement need too much sealing crack, it will need a coverlay design, proposed a maintenance decision index:maintenance index, and according to the optimal maintenance time, the maintenance index are assigned value. Finally a maintenance alternatives decision tree system was developed, using road sections verifiy this system, the result show that the alternatives accords good with the actual condition of roads.Because the limitations of our country overlay design method, this paper reference the suggested value of AASHTO old asphalt surface layer coefficient, and according to the relationship between modulus and layer coefficient, the suggested value of the modulus of old asphalt pavement was proposed, and then combining with our overlay design method, the overlay design method that based on the effective modulus of asphalt pavement was proposed, Through compareing with pavement overlay design scheme designed by foreign design methods, Prove that the design method proposed in this paper is actual, can be used to guide practical engineering; In order to analyze the role of cold-in-place recycling technology in energy conservation and emissions reduction, the designed pavement (overlay, reconstruction and recycling)should be structurally equivalent and present a similar behavior during design life, so the three different structural pavement rehabilitation alternatives were studied and compared using an energy consumption methodology, results show that the cold-in-place recycling technology alternative is the most energy saving, which worth popularization and application.