Sustainable asphalt solutions: Leveraging NaClO-ARP and modifiers for improved binder properties and environmental benefits

This study explores the use of chemical activation to enhance the compatibility of rubber powder (RP) with asphalt, addressing limitations of existing methods. Sodium hypochlorite (NaCIO) was used for chemical activation, enabling binder preparation at lower temperatures. The novelty of this research lies in enhancing NaCIO-activated rubber powder (ARP) with modifiers such as Gilsonite, polystyrene, and SBS to improve elasticity, storage stability, and overall binder quality. Oxidation of RP with NaCIO introduced functional groups that strengthened interactions with the binder, while Gilsonite improved storage stability and reduced costs. Based on previous findings about optimum content of RP and the key findings of the present study, ARP caused smaller viscosity, as a result, it becomes feasible to incorporate 15-18% ARP without compromising the workability. Low-temperature performance saw limited enhancement, but the addition of PS and Gilsonite led to notable improvements. ARP incorporation also enhanced fatigue life at medium strain levels through improved viscoelastic interactions and reduced strain sensitivity. SEM analysis revealed increased surface roughness and porosity, boosting reactivity and compatibility with asphalt, while Gilsonite promoted better adhesion in formulations. By optimizing interactions between activated rubber powder and asphalt, this study advances high-performance and environmentally friendly asphalt formulations, supporting the sustainable use of recycled rubber in pavement technologies.