Influence of Binder Properties on Dynamic Shear Response of Asphalt Mixture

For predicting the shear-related rutting potential of asphalt pavement, it is important to understand the shear response of asphalt mixture and find the link between the mixture response and component material properties. Using controlled aggregate gradation, this paper investigates the influence of bituminous binder on the response of asphalt mixture under dynamic shear loading. Four asphalt mixtures, with two different grades of bitumen, were analysed by a simple shear test apparatus with dynamic loading. The binders, both original and after short-term aging, were characterised using a dynamic shear rheometer. The modulus and phase angle of both the asphalt mixture and bitumen samples were measured. Master curves were constructed. The results revealed that the asphalt mixture phase angle maximum, where a rutting performance indicator can be obtained, appears in a relatively narrow range of shear modulus. This range corresponds to a certain level of bitumen complex shear modulus (G*) and phase angle. By temperature sweep, a temperature value can be interpolated at the specified bitumen G* level. This temperature provides a possibility to predict the frequency of phase angle maximum for a given asphalt mixture type. It is noted that the asphalt mixture phase angle maximum corresponds to a relatively high bitumen modulus level compared to other high-temperature criteria.