Research On Aging And Properties Degradation Of Materials Of Asphalt Pavements

Currently the number of highways constructed with asphalt mixtures has rapidly increased in China.As highways age,various distresses occur on road.In order to ensure the safety and comfort for motorists and passengers,the government has to carry out maintenance,which costs much time and money.Pavement maintenance management decision tools need to include a scientific solution.In this paper,the remained properties of a pavement and rheological properties of asphalt of samples cored from field were studied.Areas selected for study included several types of distresses.This study is a part of a tool to be included in pavement maintenance planning that would make a difference for decision makers.Xuanda,Tangjin,Hengde and Shihuang highways were selected for observation of the distribution of distress,and cored samples were transported to the laboratory for testing.Results indicated that various crackings exist in each highway.Less cars are being driven on the Hengde road,and its asphalt mixtures had aged for more than 11 years in the natural environment.Tangjin highway is more rut distressed.And several trucks were observed as part of traffic on Shihuang and Xuanda highways.The pavement performance of samples cored from 4 highways were studied using a UTM.The results show that samples cored from the highway with the largest number of cracking had a short fatigue life.Specimens cored from a surface layer with a huge slope of fatigue curve were more sensitive to loading.Researchers studying pavement performance need to pay more attention to the surface layer's slope of fatigue curveAged asphalts were extracted from the specimens that had experiences typical distresses.Rheological properties,four component test results and the microstructure of aged asphalt were studied using DSR,TLC and FTIR.From the DSR test,the temperature sweep showed that aged bitumen in Tangjin highway had the lowest deformation resistance within high temperature conditions.The aged asphalts from Hengde highway had the best fatigue performance.The degree of aging from the frequency sweep results of aged asphalts extracted from the surface and middle layer in Hengde highway serviced for more than 11 years are approximately similar.In the four components test,the results show that the amount of the four components of asphalt serviced and aged in the natural environment had a small difference and so the degree of aged of asphalts were almost the same.In Infrared spectrum analysis of aged asphalt test,result show that asphalt in Hengde aged highest,however,the peak area of C=O is many times higher than that of S=O.This paper also researched the pavement performance among different sections on the road.The results show that the factor of rutting and fatigue of aged asphalt in the wheel tracks were different from those in the central and shoulder sections of the road.The master curve of the complex modulus of aged asphalt in wheel tracks was highest compared to the other two road sections(shoulder and central road section),and the master curve of phase angle of aged asphalt in wheel tracks was lowest compared to the other sections.