Study on the Effect of UV Light on the Ageing Gradient Behavior of Asphalt Films
The asphalt mixtures are susceptible to oxidative ageing due to their various properties under the influence of the external environment,and there are many chemical components within asphalt that have an influence on the macroscopic properties.Based on molecular dynamics simulation and other means,this paper investigated the effect of UV light on the ageing gradient behavior of asphalt films from both a macroscopic and microscopic perspective.This paper firstly simulated the diffusion behavior of oxygen in the asphalt film at different temperatures by establishing a three-layer model of aggregate asphalt aggregate;the asphalt specimens after UV aging were layered and encapsulated,and tested by Fourier infrared spectroscopy and atomic force microscopy.The changes of chemical components of the specimens after aging were analyzed by infrared spectrograms as well as the changes of micromechanics of the specimens were studied by force diagram calculations,so as to analyze the effect of UV light on the aging gradient.The results show that the activity of oxygen molecules in asphalt film will increase with the increase of temperature,and the increase of oxygen molecule concentration will increase the probability of asphalt oxidation reaction.At low temperature,the aging of asphalt pavement is mainly affected by UV aging.With the increase of aging time,the asphalt film will flow and mix internally with the increase of aging degree difference.The aging degree of the surface layer can even drop by about 30%at most,and the aging degree will redistribute to some extent with the aging days.
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