Research Of Asphalt Mixture Rutting Prediction Model Based On Dynamic Modulus

Under long-term repeated vehicle load,there will appear different levels of ruttingdisease in asphalt pavement, the disease develops faster especially under the conditionof high temperature in summer, which seriously influences the service life and theservice quality of the pavement,also endangers vehicle safety.For a long time, the roadscientific researchers analysis the mechanism of asphalt pavement rutting from asphaltmixture performance or asphalt pavement structure,or from the effects of the externalconditions of pavement rutting, using different methods to forecast permanentdeformation of asphalt road.Researchers pointed out that dynamic modulus anddynamic modulus indicator of asphalt mixture closely related with its high temperatureperformance, as well as verified the correlation between dynamic modulus and dynamicmodulus indicators and permanent deformation of asphalt pavement, tried to use thedynamic indicator to study the asphalt pavement rutting problem.Based on this, firstly,we performed the rotation compaction test and dynamicmodulus test of indoor asphalt mixture with the aid of the rotating compaction tester andsimple performance tester (SPT),and analysed the influence law of test temperature,loading frequency, loading stress, mixture volume indicators (such as VV, Vbeff, etc.)and mixture gradation of mixture on dynamic modulus and phase angle. According tothe time temperature equivalent principle,using the nonlinear least squares to regressionfitting the shift factors between different temperature,we established the dynamicmodulus master curves, obtained the master curve equations.Then according to the basicideas of the dynamic modulus Witczak forecast model and Sigmoidal functionequation,by considering test temperature, loading frequency, loading stress, mixturevolume indicators and grading characteristics,and using marquardt optimization algorithm we obtained the dynamic modulus of asphalt mixture forecast model, and theforecast model are verified.The results showed that the forecast model had goodgenerality.Dynamic modulus and dynamic modulus indicators can reflect dynamiccharacteristics of asphalt mixture under vehicle load,the analysis result showed therewere strong correlation between dynamic modulus and dynamic modulus indicators andthe rut deformation.Through indoor standard rutting test and full thickness rutting test ofimproved rut tester,we get rut deformation law of single, double and full thicknessspecimens under different temperature, thickness, gradation and load.Through theanalysis of asphalt layer thicknesses, numbers of load, the dynamic modulusindicators,driving speed,etc. Combined with the finite element calculation,and using thethought of the layer deformation superposition, this paper proposed a new forecastmodel.Then using the basic principle of genetic algorithm,and writting thecorresponding program, according to the test data we fit the correlation coefficients ofthe forecast model.By further testing, we validate the model by using full thicknessrutting test data under different temperature, different load. The results show that themodel can reflect the deformation law of asphalt road surface under different conditions,and also show that the forecast model has good applicability,which has good guidingsignificance on prevention and cure of actual rutting disease of asphalt pavement.