Study On The Technical Performance And Numerical Simulation Of Asphalt Mixture Added With Anti-rutting Additive

With the growth of the volume of the traffic, aggravation of axis and canalization of traffic, the rutting of asphalt pavement has become the first ones of premature destroy phenomenon. Compared with cracking and moisture damage, the danger of the rutting is worse. It not only seriously affects the service level of the pavement, but also remarkably reduces the service life. And the rutting is most difficult to maintain, so some countries take the rutting as the most exigent problem to solve. In many technique measures which improve asphalt pavement surface the capability against rutting, the anti-rutting additive provides us an entirely new technique measure.Firstly this paper discusses the method of XLPE modification. Based on the characteristics of XLPE, the wet method and the dry method are designed. Through the study on pavement performance tests, the dry method of XLPE modification is considered the best effect.To investigate the influence of the anti-rutting additive on the performance of asphalt mixture deeply, Haichuan, LF8000, XLPE and PRI are chose to test. The experimental research are including: using the different types of the gradation (type C and type F)and different types of basic asphalt (A-70 and A-110) to do the mixture design, test the pavement performance such the stability as high temperature, the thermal crack resistance and the water stability, and make a comparison with the SBS modified asphalt. The method of statistical analysis is employed to analyze the influence of the anti-rutting additive, the dosage of it, the type of gradation and the type of basic asphalt on the asphalt mixture performance.Based on fracture mechanics theory, the thesis discusses the influence of the fatigue precracking, the thickness of specimen beam and the radius size of plastic area around crack tip on the fracture toughness of asphalt mixture at low temperature by single edge notched bend (SENB) fracture test method. Based on upper research, the influence of anti-rutting additive, the dosage of it, basic asphalt and gradation on the fracture toughness of asphalt mixtures are studied deeply.Using nonlinear finite element methods, the four-parameter creep model and a simple asphalt pavement structure, the thesis calculates pavement's permanent deformation of base asphalt, SBS modified asphalt, asphalt mixture by XLPE and PRI after 10000 times standard axle load at 48℃. According to these crunodes vector displacement, the law of shear flow of pavement material under the load circle is analyzed. In order to further understand the low-temperature cracking phenomenon of asphalt pavement, using simulation of thermal-mechanical coupling to establish two-dimensional asphalt pavement structure model which contains different length of cracks, numerical simulation calculation is carried out on the temperature field, stress field and stress intensity factor of base asphalt, SBS modified asphalt mixture, modified asphalt mixture by XLPE and PRI. Safety factor and fracture resistance are employed to judge and evaluate the thermal crack of asphalt pavement. Allowable crack length is put forward as the index of asphalt pavement's anti-crack performance. And reasons which cause the defects of asphalt pavement are simply discussed.Based on the study of the deformed particle morphology of the anti-rutting additive reclaimed from the extraction test, C and f of the mixture, the mechanism that anti-rutting additive affect asphalt mixture performance is analyzed in depth.