Study On Viscoelastic Mechanical Properties And Self-Healing Properties Of High Viscosity Modified Asphalt

Because of the complexity of its working environment,the damage factors of asphalt pavement are diverse.The asphalt mixture has a certain self-healing time when the microcrack occurs.The load loading mode of the real pavement vehicle is analyzed.The intermittent fatigue loading mode plays a good role in evaluating the fatigue performance of the asphalt mixture.The performance of high viscosity asphalt mixture with healing effect is less affected.In this paper,the self-healing performance of high viscosity asphalt is analyzed by evaluating the mechanical response of high viscosity asphalt under dynamic load and combining with the flow characteristics of high viscosity asphalt.Firstly,by analyzing the variation of viscosity under different temperature conditions,the variation of shear stress is measured at different temperature and different shear rate,and the viscosity-temperature characteristics and flow properties of high viscosity asphalt are evaluated.Secondly,based on the dynamic loading mode,the variation characteristics of viscous elastic parameters and the variation trend of modulus principal curve of high viscosity modified asphalt are studied,and the high temperature performance and stress sensitivity of high viscosity modified asphalt are evaluated by multiple stress creep recovery test,which plays an important role in analyzing the mechanical properties of high viscosity modified asphalt.Finally,combined with molecular diffusion theory,based on DSR dynamic shear test,the self-healing degree of high viscosity modified asphalt at different healing time was studied.The experimental results show that the flow index of type I high viscosity asphalt increases gradually with the increase of temperature,and the closer it is to Newton fluid,the SBS modified asphalt tends to Newton fluid state when the temperature is higher than 175?,and compared with the Rdiff,Jnr-diff value of three kinds of high viscosity modified asphalt,addition of high viscosity modifier plays a certain role in lifting the stress sensitive type of modified asphalt.Through the study of macro healing performance,it is found that the addition of high viscosity modifier has a good effect on improving the instantaneous healing performance of asphalt.Type I high viscosity asphalt is superior to type ? in short-term or long-term healing effect,which indicates that type I high viscosity additive is better at improving the self-healing performance of asphalt mixture under external load when there are microcracks in asphalt binder.