Study Of Evaluation Index Of High-temperature Stability And Design Methodology For Asphalt Mixture

Through the field investigation of rutting of asphalt pavements in Shaanxi province expressway and analysis of grading curve and the composition of asphalt mixture in different road session, we have good reason to believe that the existing asphalt mixture design method is not able to meet the requirement of heavy load traffic and the shear flow deformation is the main reason of rutting in pavement, so improving the anti-shear ability of asphalt mixture is the key of solve the problem of rut in pavement.Through analyzing merit and shortcoming of different permanent deformation test methods and evaluation index of asphalt mixture, it was found that dynamic stability indictor in standard was not fit to evaluate permanent deformation of asphalt mixture. Based on the compaction theoretical analysis, this paper put forward a new evaluation index—Complex Stability Index to evaluate the high-temperature Stability of asphalt mixture comprehensively considering compaction period of transition and compaction stability period and give the calculation formulas of Complex Stability Index using present rutting test equipment. Though building the correlation model between Complex Stability Index and stiffness modulus, author proved the rationality of Complex Stability Index.Through building the model of granular material mechanics, author acquired the formula of Shear Modulus. Through the analysis of different spheres arrangement model, author acquired the linear relation between relative density and the numbers of contact areas in unit volume, which afford the mechanics basis to test the Shear Modulus of coarse aggregate.According to the theory of multilevel filling, this paper put forward a new grading design method (the Multilevel Anti—Shear Grading Design Method) to improve the anti-shearing ability of asphalt mixture. a example of design is given and experiment is done to test the pavement performance, and through comparing the pavement performance of MAS-20 to other grading asphalt mixture, the test result showed that the MAS-20 have good high-temperature stability and water stability, which proved the rationality of Multilevel Anti—Shear Grading Design Method.