Work

The Influence of Modifiers on the Performance of Recycled Asphalt Mixtures

Year: 2025

Type: article

Abstract: To enhance the performance of reclaimed asphalt pavement and evaluate its suitability under severe environmental conditions, this study systematically assessed the reinforcing effects of two modifiers: styrene–butadiene rubber (SBR) and polyurethane (PU). The stability and mechanical properties of mixtures with varying recycled asphalt contents were tested, with a focus on the effects of water immersion and high-temperature (150 °C) aging. The underlying mechanisms were elucidated using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). Results indicate that recycled asphalt incorporation significantly degraded the mixture’s performance; stability and mechanical strengths decreased with recycled asphalt content following a cubic function, with maximum deterioration rates of 37.3%, 67.2%, 73.6%, and 72.1%. Water and thermal aging further accelerated performance decay, with deterioration rates reaching up to 61.2% and 63.9%, respectively. Modifiers effectively counteracted this trend: SBR and PU enhanced the aforementioned properties by up to 102.6%, 50%, 60.3%, and 56.9% and 139.5%, 81.4%, 113.2%, and 120.3%, respectively. Microstructural analysis revealed that RAP led to decreased C and O contents, increased Si and Fe presence, and a more porous structure. In contrast, the modifiers increased binder content and interfacial density. This research provides a theoretical foundation and technical pathway for the engineering application of high-performance recycled asphalt mixtures in complex environments.

Source: Coatings

DOI: 10.3390/coatings15121432