Research On The Rut Of Asphalt Pavement In Beijing Full-scale Pavement Test Loop

Asphalt pavement is mainly used in expressways in China,and rutting is one of the most serious diseases of asphalt pavement in high-grade highways.Accurate research on the rule of rutting development and change can play a guiding role in pavement design,and can also provide reference for the later maintenance and maintenance of pavement.The dynamic modulus of asphalt mixtures with different asphalt materials and gradations was tested by SPT simple performance tester.The variation of dynamic modulus of asphalt mixtures with test temperature and loading frequency was analyzed.The dynamic modulus of asphalt mixture has the same trend with the test temperature and loading frequency.With the increase of temperature,the dynamic modulus decreases obviously,and with the decrease of loading frequency,the dynamic modulus decreases gradually.In the test temperature range,the dynamic modulus of asphalt mixture with the same gradation decreases with the increase of asphalt label.Especially at high temperature of 50#and 70#asphalt,the dynamic modulus of 50#and 70#asphalt is 35%lower than that of 30#asphalt.By studying the principal curve of dynamic modulus and the principal curve of phase angle,the dynamic modulus and phase angle at the extended temperature of 60 C are obtained,and the evaluation index values of dynamic modulus at this temperature are obtained.According to the good correlation between the evaluation index of dynamic modulus of asphalt mixture and the relative deformation of rutting,the Origin software is used to define the fitting function,and the correlation coefficient of the prediction model is obtained by using the thickness H,cumulative loading times N and dynamic modulus index |E*|/sin_as independent variables of 10 kinds of asphalt mixtures,AC-13,AC-20 and AC-25.A rutting prediction model of asphalt mixture based on indoor test is established.The prediction of pavement rutting based on the model needs to be corrected and verified by the loading data of the test loop at the later stage.The internal factors affecting the rutting depth of asphalt pavement are mainly the thickness of asphalt pavement,the type of asphalt mixture and the combination of the whole structure.The external factors are mainly temperature and uniaxial load.With the increase of temperature,the cumulative deformation increases first and then decreases.When the temperature is close to each other,the increase of the single axle load will not cause the rutting to increase significantly.Through standard rutting test,Hamburg rutting test and French rutting test,21 kinds of asphalt mixtures in ring road are tested for high temperature rutting resistance and compared with the pavement structure depth measured after 7.37 million times of action of standard axle load in ring road.The results of high temperature rutting evaluation are not entirely consistent.Through the analysis of temperature data detected by temperature sensor embedded in full-scale loop,the variation rule of temperature inside structure with pavement depth is obtained.The rutting simulation of STR19 structure is carried out by using the measured temperature field and the cumulative number of standard axle loads.The measured and calculated values of the three structures all show the same rule.Based on the analysis of the rutting results of full-scale test ring road,the rutting change of test ring road is still in the stage of compacted rutting.The main influencing factor is asphalt material.The rutting resistance level of pavement structure paved with 30#asphalt is better than that of other kinds of asphalt materials.