Study On Fatigue Performance Of RCA High Modulus Modified Asphalt And Modified Asphalt Mixture

With the continuous growth of traffic volume,the fatigue damage of asphalt pavement is becoming more and more serious.How to prolong the service life of pavement and reduce the waste of resources caused by maintenance or reconstruction has become a hot research topic in the industry.Research shows that improving the anti-fatigue performance of asphalt and asphalt mixture is one of the important ways to solve the above problems,and asphalt modification is an effective way to improve its anti-fatigue performance.At present,there are many kinds of asphalt modifiers with different performances,and RCA(Rock Compound Additive)high modulus modified asphalt can solve the problems of complex preparation and segregation of conventional SBS modified asphalt.The research results of anti-fatigue performance of modified asphalt and asphalt mixtures at home and abroad are not uniform,and the fatigue performance of RCA high modulus modified asphalt has always been the focus of research.Therefore,it is necessary to carry out anti-fatigue on RCA high modulus modified asphalt.Through the preparation of RCA high modulus modified asphalt,the asphalt with different RCA high modulus modifier content was tested by three indexes and Brockfield viscosity test,and the changes of basic performance were compared and analyzed,and the optimum blending ratio range was determined.The mechanism of performance change of RCA high modulus modified asphalt was discussed by Fourier transform infrared spectroscopy(FTIR)from a chemical point of view.The results show that RCA high modulus modifier swells at high temperature,improves the performance of asphalt,and does not produce new chemicals,so it is physical modification.The Linear amplitude sweep(LAS)test of asphalt was carried out by dynamic shear rheometer(DSR),and the fatigue life of asphalt was analyzed based on viscoelastic continuum damage model(VECD)to determine the optimal blending ratio.The results show that the service life of RCA high modulus modified asphalt is longer than that of base asphalt under low strain.In the data processing of LAS test,it is found that the phase angle-strain curve is disordered.According to this phenomenon,a new fatigue failure criterion is put forward,and the asphalt mixture is verified.The preparation of RCA high modulus modified asphalt mixture with matrix asphalt mixture and optimum blending ratio.The four-point bending fatigue life test of two kinds of asphalt mixtures is carried out,and the fatigue performance of two kinds of asphalt mixtures under different strains is analyzed,and the fatigue life of two kinds of asphalt mixtures under the same action is compared.The results show that compared with the matrix asphalt mixture,the fatigue resistance of RCA high modulus modified asphalt mixture is enhanced.According to the new fatigue failure criterion of asphalt proposed in this thesis,the existing fatigue life prediction model of asphalt mixture is improved,and its rationality is verified.The proposed model can directly predict the fatigue life of asphalt mixture by simple and quick LAS test,which has certain economic value.