Research And Analysis On Permanent Deformation Law And Rutting Prediction Model Of Asphalt Mixture Layer

Driving speed significantly affects the high temperature permanent deformation of asphalt mixture,but the influence of load frequency is not considered in the rutting prediction model of asphalt mixture in the current code.Based on this consideration,in the current specification indoor rutting prediction model on the basis of added rutting test method,developed based on the MTS experimental system of rutting test fixture,design the MTS rutting test program,introduced the load frequency parameters,preliminary built include temperature,pressure,loading frequency,void ratio and load frequency parameters of asphalt mixture layer of permanent deformation forecast model.On the basis of 219 specimen data of JTG D50,MTS rutting test of 120 specimens of three asphalt mixtures was added at 40℃,50℃ and 60℃,respectively.The test axial load stress was set as 0.7MPa.The test frequencies were 1Hz,2Hz,2.9Hz,5Hz and 10Hz;The test time was continuous loading for 3h.Through multiple regression analysis,an indoor prediction model for permanent deformation of asphalt mixture layer was established based on MTS test,including temperature,pressure,loading times,void ratio and load frequency.Through the small scale full environment temperature control accelerated loading test machine,the high temperature rutting accelerated loading test of the semi-rigid base asphalt pavement cutting specimen of Ji-Qing Expressway was carried out at 60℃,and the rutting prediction model of asphalt mixture modified by the accelerated loading test was established.The prediction model has a good linear relationship with the JTG D50 indoor rutting prediction model,and its prediction accuracy is higher than that of the JTG50 indoor rutting prediction model.The field accelerated loading tests of asphalt pavement under three different temperature environments of 60℃,45℃ and 30℃ were carried out.Based on the rutting depth of the field pavement at different temperatures,the relationship between the rutting depth of asphalt layer on the semi-rigid base asphalt pavement in service and the temperature change was analyzed,and the development and evolution law of the asphalt layer’s permanent deformation on the in-service pavement was revealed.Temperature is an important factor affecting the development of pavement rutting.In the medium and low temperature environment,the development of pavement rutting is slow,but in the 60℃environment,the development of pavement rutting is fast.The permanent deformation of semi-rigid base asphalt pavement has gone through the initial rapid development stage,the middle stable creep stage and the late rapid destruction stage.