Investigating Asphalt Rejuvenators from Biowastes Based on Their Wetting, Diffusion, and Compatibility

Achieving NetZero carbon emissions necessitates innovative solutions for revitalization and recycling of asphalt pavements. This study focuses on the efficacy of biobased rejuvenators in enhancing the properties of aged asphalt binder, emphasizing their diffusion, wetting, and compatibility. We discovered that low-viscosity rejuvenators, specifically palm oil and waste cooking oil, significantly improve wetting, with rates of 79.2 and 317.2 mm/s, respectively. The diffusion rate was found to correlate with chemical composition and viscosity, with palm oil leading, followed by soybean and castor oils. Compatibility assessment, based on the thermodynamic free energy of mixing, Han curve analysis, and Cole–Cole plots, revealed that palm oil effectively restored the molecular and colloidal structures of aged asphalt. These findings underscore the significance of rejuvenator compatibility for optimal performance and sustainability, contributing to the advancement of NetZero carbon road infrastructure.