Study on the performance of PU-SBS composite modified asphalt

With the growing severity of road traffic noise pollution, poroelastic road surfaces (PERSs) have garnered significant attention due to their excellent noise reduction performance. However, the unique structure of PERSs results in insufficient durability, which limits their practical application. This study aims to develop a novel type of composite-modified asphalt that addresses the technical challenge of simultaneously improving low-temperature performance and durability, thereby providing a solid material foundation for boosting the engineering application of PERS pavements. Firstly, polyurethane (PU) and styrene-butadiene-styrene (SBS) are utilized to modify 90# matrix asphalt, resulting in the fabrication of a composite material. The basic properties of the composite-modified asphalt material are examined through penetration, ductility, softening point, segregation, and aging tests. Further, dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests are employed to assess its rheological behavior at high and low temperatures. Next, fluorescence microscopy and atomic force microscopy are used to analyze the micro-modification mechanism of the multiphase system. The results reveal that the PU-SBS composite-modified asphalt exhibits significantly improved low-temperature ductility compared with the matrix asphalt, while also maintaining excellent high-temperature performance and fatigue resistance at medium temperatures. Microscopic characterization suggests that a chemical reaction between PU-2 and SBS-modified asphalt leads to the formation of a stable system. This modification process not only enhances the performance of the composite asphalt at both high and low temperatures but also ensures excellent storage stability. Overall, the proposed PU-SBS composite-modified asphalt effectively resolves the conflict between strength and flexibility in poroelastic pavements. The synergistic mechanism of strong interfacial interactions and physical filling at the microscopic level provides a theoretical basis for the design of modified asphalt. These research findings offer a comprehensive technical solution for the widespread adoption of new environmentally friendly pavements.