Effect of asphalt binder oxidation on the modulus of asphalt concrete mixtures

Oxidative aging of asphalt binder is a well-known phenomenon that has been studied by numerous researchers. Significant breakthroughs have been made in the fundamental understanding of this phenomenon at the asphalt binder level, and practicing engineers now have the tools needed to quantitatively assess the oxidative aging potential of these materials. Conversely, pavement engineers do not have a reliable method to assess the oxidative aging potential of an asphalt mixture because it is unclear exactly how aging in the asphalt binder affects the behaviour of asphalt mixture. Analysis that supports the use of existing models for this purpose is shown in this paper. The study begins with an examination of the effects of oxidative aging on binder and mixture moduli. Then, four existing predictive models that relate these moduli are examined. It is found that all four models do an adequate job of predicting the effect of asphalt binder oxidation on asphalt mixture modulus, but that two of the models, the Witczak models, match the trends observed in mixture experiments the best.