Asphalt-aggregates interface interaction: Correlating oxide composition and morphology with adhesion

The adhesion between asphalt and aggregates is a complex physicochemical interfacial interaction that plays a critical role in determining the durability of asphalt pavement. This paper aims to investigate the determination mechanism of oxide composition and morphology of aggregates to their interfacial interaction and adhesion with asphalt, thereby optimizing the adhesion evaluation indicators of aggregates. Herein, the adhesion and interaction properties of aggregates were evaluated by photoelectric colorimetric, water boiling methods, and dynamic shear rheometer. The morphology and chemical compositions of 11 aggregates were characterized using X-ray diffraction, X-ray fluorescence, and scanning electron microscopy, thereby classified into 3 categories based on their oxide composition. The results indicate that the chemical composition of the aggregates is a crucial factor influencing adhesion rates, while micro-roughness impacts adhesion rates to varying degrees across different aggregate groups. Oxide composition was found to be a reliable predictor of adhesion properties, and incorporating surface roughness indicators improved the accuracy of adhesion rate prediction models. Both rheological indicators proved effective in characterizing the adhesion properties of aggregates, though they exhibited varying sensitivities depending on the aggregates categories.