Nonlinear Differential Dynamics Model Of Properties Attenuation Of Recovered Binders From Weathered Asphalt Mixtures

Aging of asphalt binders is one of the main causes of asphalt pavement damage.In order to improve the service life of asphalt pavement,improving the anti-aging performance of asphalt binders is necessary.How to explain the aging mechanism of and predict the life of asphalt binders has important social and economic significance.This paper focused on establishing the dynamic equations between the asphalt binder performance and aging time,describing the relationships between properties of asphalt binders and weathering factors.Whether or not the matching rate of asphalt mixtures was an aging factor was explained as well.In this study,stone matrix mixture(SMA)and asphalt concrete(AC),were at first weathered for 0h,1,000 h,2,000 h and 3,000 h respectively,and then asphalt binders were recovered.The performance tests of aging asphalt included Atomic Force Microscopy,Gel Permeation Chromatography,Fourier Transform infrared spectroscopy,Dynamic Shear Rheological and Rotation Viscosity tests.About microscopic properties,this paper chose the Verhulst model to describe the dynamic relationship between microscopic composition and the mechanical properties of asphalt binders and weathering time.The results showed: 1)with the increase of aging time,morphology,content of small molecules and butadiene were reduced,and the adhesion,modulus,the content of large molecules,the molecules,carbonyl and sulfoxide were on the rise;2)there were sound correlations between the measured and calculated values,which means the selected model was realiable;3)the equation parameter r could reflect the aging rate,and L could reflect the aging degree.This paper introduced the theory of thermal analysis kinetics,considering both the aging time and temperature on the properties of asphalt,to show how the macroscopic properties changed.The results are: 1)the rutting factor and viscosity increased with the increase of weathering time and with the increase of temperature,and the aging equation could well reflect the tendency of the properties of asphalt binders;2)the activation energy of AC-13 in the aging process was lower than that of SMA-13,indicating that the aging rate of AC-13 was faster and the aging was worse.