Study On Effect Of Thermal Oxidative Aging Intensity And Regeneration On Properties Of Asphalt And Its Mixture

As the main pavement type,asphalt pavement' binder-asphalt inevitably cause aging.Thermal oxidative aging is the main aging method of asphalt.Probing the evolution law of asphalt and its mixture under different thermal oxidative aging intensity has important guidance for prediction and prevention of asphalt pavement aging.At the same time,a large number of experimental studies have shown that adding rejuvenating agent or new asphalt can restore the performance of asphalt and asphalt mixture,and the recycled asphalt mixture cannot only be directly used in asphalt pavement,but also can save huge cost.In this paper,the properties of asphalt and asphalt mixture under different thermal oxidative aging intensity were studied,and the performance evolution of asphalt and asphalt mixture under different thermal oxidative aging intensity were analyzed.In addition,Arrhenius viscosity harmonic method was used to regenerate asphalt under different thermal oxidative aging conditions..The change law of asphalt and asphalt mixture after regeneration was studied.The main conclusions are as follows:(1)For Changlian 70# asphalt,the aging intensity of 3 cycles of rolling film oven test(RTFOT)is very similar to that of 1 cycle of RTFOT+pressure aging vessel(PAV).At the same time,it is found that as the thermal oxidative aging intensity increases,the increment of the asphalt's complex modulus(G*)gradually decrease,and when the aging reaches a certain level,G* tends to a stable value.(2)The asphalt was regenerated by Arrhenius viscosity harmonic method.The penetration degree of the asphalt restored to the level of the matrix asphalt,and the ductility not only restored to the level of the matrix bitumen,but also improved.However,the softening point did not return to the matrix asphalt level,and the error cannot be ignored.At the same time,G* basically restored to the matrix asphalt level,but the phase angle(?)at high temperature cannot restored to the matrix asphalt leve.(3)The asphalt mixture by many cycles of RTFOT aging has better rutting performance under light load,but the deeper of the mixture aging under heavy load,the worse the rutting performance.At the same time,its water stability performance decreases with the increase of aging intensity.Compared other asphalt mixtures,the asphalt mixture after 2 cycles of RTFOT aging has the best high temperatureperformance but the lowest temperature crack resistance and fatigue performance.(4)Asphalt mixture aged by many cycles of RTFOT was regenerated,and its high-temperature rutting performance is lower than the matrix asphalt mixture rutting performance,and low-temperature anti-crack performance and water stability can be basically restored to the level of matrix asphalt mixture.Fatigue performance can be restored to the level of the matrix asphalt mixture,and it is also strengthened at high temperatures.