Rutting Numerical Simulation Of Asphalt Pavement Based On Dynamic Modulus

With the increasing traffic volume and vehicle overload,rutting problem becomes more and more serious,which affects the performance and durability of asphalt pavement.Load is one of the most important factors affecting the rutting performance of asphalt pavement.In order to explore the influence of load on the rutting performance of asphalt pavement,dynamic modulus test is used to obtain dynamic modulus and phase angle,and material adhesion is obtained by calculation and fitting.Elastic parameters,using finite element method to establish asphalt mixture rutting test model,simulate indoor rutting test,and compare with indoor rutting test.After verifying the reliability of the model,rutting simulation test of asphalt mixture under different loads is carried out to analyze the impact of load on asphalt mixture rutting.Then the finite element calculation model of asphalt pavement structure is established to study the rutting development law of asphalt pavement under different loads.The dynamic modulus and phase angle of AC-13,AC-16,AC-20 and AC-25 asphalt mixtures were tested at temperatures of 4.4,15,20,40 and 54.5,and test frequencies of 20 Hz,10 Hz,5 Hz,1 Hz,0.5 Hz and 0.1 Hz.The dynamic modulus and phase angle were obtained,and the experimental results were calculated and plotted.The relative dynamic modulus and phase angle of temperature and load frequency were found through analysis.The law of sound and the trend of development.The constitutive model of asphalt mixture is obtained by fitting the dynamic modulus test results with Prony series.The finite element method is used to simulate the rutting.It is proved that the correlation coefficient is 0.99 compared with the indoor rutting test,which proves that the finite element method can be used to study the rutting performance of asphalt mixture.In the process of calculating and fitting the parameters of Prony series viscoelastic model for asphalt mixture dynamic modulus test results,the dynamic modulus |E*| in frequency domain is converted into relaxation modulus E(t)in time domain by Schapery and Park method.According to the principle of time-temperature equivalence,the material constants C1 and C2 are obtained by WLF equation,and the Sigmoidal function is fitted by Mcquart LM optimization algorithm to obtain displacement.Factor and main curve of relaxation modulus of asphalt mixture transform the constrained multi-variate non-linear curve fitting into programming problem.Using Mcquart LM optimization algorithm to fit Prony series,the parameters of viscoelastic model expressed by Prony series are obtained,which provides a basis for finite element simulation.According to the established finite element model,the application of simulating asphalt mixture rutting and asphalt pavement is carried out.The asphalt mixture is simulated and analyzed by numerical simulation.The static equivalent relationship is simplified for overloaded vehicles according to different axle loads.The rutting depth of asphalt mixture under different wheel loads is analyzed,and the influence and law of different wheel loads on Rutting deformation rate are studied.The rutting deformation map of asphalt mixture under different wheel loads was used to analyze the rutting morphology.By numerical simulation of rutting on asphalt pavement under different axle loads,the rutting depth curves under different axle loads are analyzed.It is found that the asphalt mixture conforms to the three-stage permanent deformation law.The rutting development rate and acceleration under different axle loads are obtained by two differential derivatives.The critical life of rutting is calculated,and the rutting development law at each stage is obtained through analysis.At the same time,the axle load of 200 kN is obtained.When the rutting critical life is more than four times lower than that at 100kN,overloading will shorten the pavement life,make the pavement quickly enter the damage stage and reduce the pavement life.