Effect of aggregate–bitumen compatibility on moisture susceptibility of asphalt mixtures

Stripping of an asphalt mixture is reached when the interaction between bitumen and aggregate weakens by effect of water. The identification of bitumen–aggregate pairs with higher adhesion is key to obtain pavements that are more resistant to stripping. In order to research the adhesion and debonding processes further, several bitumen and aggregate combinations were prepared and their compatibility was estimated by means of surface energy measurements. Additionally, the water susceptibility of the proposed bitumen–aggregate combinations was mechanically tested by means of loss in storage modulus of samples exposed to water. It was found that the compatibility of water to bitumen and aggregate describes the mechanical behaviour of the asphalt mixture. One of the features of this study is the evaluation of the effect of physicochemical properties of bitumen and aggregates on the striping susceptibility of the given combinations and the corresponding correlation to the field performance of an asphalt mixture.