Preparation and ageing resistance enhancement of RP/SBS composite asphalt by heterostructure copper oxalate nanoparticles/recycled polypropylene fiber

Abstract

Although the effectiveness of different types and morphologies of polymers in improving asphalt performance varies significantly, it offers a pathway to achieve high-performance and durable modified asphalt. In current asphalt modification research, recycled polymers are one of the leading candidates. It helps alleviate environmental risks associated with polymer waste and enables the transformation of waste materials into valuable resources for producing high-performance modified asphalt. However, the inherent surface inertness of recycled polymers poses a significant challenge, negatively impacting the durability of modified asphalt in applications. Therefore, further research is needed to explore how surface modification and structural design of recycled polypropylene fibers can enhance the performance of modified asphalt. This study adopts a Schiff base reaction combined with an in-situ design approach to preparing heterostructured copper oxalate nanoparticles/recycled polypropylene fibers (RP@PDA-PEI@CO) and high-performance composite SBS-modified asphalt. Experimental results demonstrated that recycled polypropylene fibers modified via the Schiff base reaction (RP@PDA-PEI) significantly improved the rheological properties of the asphalt. Specifically, the storage modulus (G'), loss modulus (G′'), and rutting resistance parameter (G*/sinδ) at 55°C increased by 77.93 %, 72.42 %, and 74.46 %, respectively, compared to unmodified recycled polypropylene fibers (RP). The combination of Schiff base reaction and in-situ design (RP@PDA-PEI@CO) significantly enhanced the ageing resistance of the modified asphalt. Compared to RP, the carbonyl content was reduced by approximately 50.43 % after short-term ageing and 36.8 % after long-term ageing. The Schiff base reaction and in-situ design strategy activated the inert interface of recycled materials and improved the overall performance of modified asphalt. These findings provide an innovative design concept for preparing and applying advanced modified asphalt, offering a sustainable and high-performance solution for the construction industry.