Evaluation of rheological properties and mechanism of modified asphalt using peanut biomass waste

This study employed peanut-derived biomass waste, including waste peanut oil (WPO) and acid-treated peanut shells (APSs), as composite asphalt modifiers to address resource scarcity and environmental pollution associated with petroleum-based asphalt. Conventional physical tests, rheological evaluations, contact angle measurements, and microscopic analyses (FT-IR, SEM, and fluorescence microscopy) were conducted. WPO significantly enhanced low-temperature flexibility and stress relaxation. At dosages of 1% and 2%, the creep modulus decreased by 48.1% and 72.2%, while the creep rate increased by 5.5% and 9.8%, respectively. However, high-temperature stability declined, with G* reduced by up to 31.1%. APS effectively compensated for this drawback by limiting the softening-point reduction to 1.1 °C and restricting the decrease in G* to 5.6%. Microscopic observations confirmed uniform dispersion and improved interfacial compatibility in the composite-modified asphalt. This study demonstrates the technical feasibility of utilizing biomass waste in sustainable pavement engineering.