Research On Technical Improvement Of Asphalt Pavement On Expressway

Conventional maintenance schemes can not solve the problem of structural performance degradation of Expressway pavement.Combining with the pavement maintenance project of Ningtong Expressway Guang-jiu Section,this paper studies the long-term performance improvement technology of asphalt pavement,which mainly includes four aspects: asphalt pavement condition evaluation,structure condition evaluation based on field core sample,new maintenance material technology based on pavement performance and maintenance structure combination based on functional requirements of structural layer,so as to provide meaningful reference of improving the durability and durability of original pavement.Firstly,through collecting and analyzing the pavement testing data of Guang-jiu section of Ningtong Expressway over the years,the maintenance history,pavement damage,pavement smoothness and rutting are evaluated.It is found that the overall PCI,RQI and RDI indexes of the pavement are good,and the overall condition of the pavement is good,only some sections have obvious diseases.At the same time,data analysis over the years shows that PCI and RDI are decreasing year by year,and the decline rate is accelerating,indicating the necessity of maintenance engineering.Secondly,based on the field core samples,the performance and structure of the original pavement material are evaluated,including the core characteristic state evaluation,the strength attenuation,high temperature performance and fatigue resistance of the original pavement material.The results show that the thickness difference between the surface layer and the base layer of Guangjiu section of Ningtong Expressway is large,the bond between the layers is poor,and the hightemperature performance of the upper layer material is obviously attenuated.At the same time,the fatigue performance of the surface layer decreases rapidly,while the base material still has good fatigue resistance.The maintenance of the surface layer can basically meet the requirements of road performance and overall structure.Then,three new maintenance materials based on road performance are studied.Relevant test results show that U-PAVE10 ultra-thin pavement abrasive layer material has excellent comprehensive pavement performance of low temperature crack resistance and high temperature rutting resistance;rubber asphalt mixture AR-SMA-13 has good fatigue resistance and elastic recovery performance,and can better resist reflective cracks;composite high modulus asphalt mixture EME-14 has good high temperature performance,which can greatly reduce the original pavement structural layer.The stress can improve the service life of the original pavement material.Finally,through the study of maintenance structure combination based on functional requirements of structural layer,a milling and paving maintenance scheme using composite high modulus EME-14 + rubber asphalt AR-SMA-13 is proposed.The long-term performance of the pavement structure is analyzed by mechanical analysis method.The results show that the anti-rutting and anti-fatigue performance of the pavement structure can be effectively improved by increasing the modulus of the middle surface layer.