Investigation of the Adhesion Characteristics of a Novel Fast-Melting SBS-Based Modifier to Asphalt-Aggregate Systems Based on a Multiscale Approach

Abstract

A fast-melting styrene-butadiene-styrene-based modifier (SBS-T) was applied for rapid modification for asphalt mixtures. No relevant studies are available to support the effect of this new fast-melting modifier on asphalt-aggregate adhesion properties, and this paper is to remedy the assessment of the adhesive properties of the modified SBS modifier in asphalt mixtures. At the micro-scale, the sessile drop method is utilized to measure the contact angle of bitumen and aggregate and to compute thermodynamic parameters based on surface energy theory. Meanwhile, the effects of short-term and ultraviolet (UV) aging on the thermodynamic parameters of SBS-T modified asphalt (SBS-T-MA) were investigated. The asphalt-aggregate adhesion properties were further verified on a macro-scale scale by pull-off tests. The outcomes suggested that the higher the dosage of SBS-T modifier, the better the thermomechanical characteristics of the bitumen binder. The adhesive properties of SBS-T-MA and aggregates were promoted in short-term aging and decreased in UV aging. Statistical analysis of the pull-off test indicated a significant correlation between pull-off strength and energy ratio. It was demonstrated that adhesion damage occurred between asphalt and aggregate in the pull-off test and that the greater the energy ratio between asphalt and aggregate, the greater the asphalt-aggregate pull-off strength.