Laboratory evaluation of the rejuvenation efficiency of biomass-derived phenolic oil on the asphalt binder with various aging conditions

Rejuvenators are critical for restoring the performance of recycled asphalt pavement produced with a high dosage of reclaimed asphalt pavement (RAP) materials. In this study, a biomass-derived phenolic oil (BDPO) recycled from biomass pyrolysis was proposed as a novel rejuvenating agent. Its rejuvenation efficiency and mechanism on the asphalt binder aged with three laboratory-aging conditions, including the rolling thin-film oven (RTFO) aging, pressure aging vessel (PAV) aging, and ultraviolet (UV) radiation aging, were investigated systemically. The chemical components of BDPO were first identified through the Gas-Chromatography-Mass Spectrometry (GC–MS) analysis. The rejuvenation efficiency was subsequently evaluated on the laboratory-aged asphalt binders using typical physical-rheological properties tests and compared with two commercial rejuvenators. The rejuvenation mechanism of BDPO was finally revealed by the Fourier Transform Infrared Spectroscopy (FTIR) test. Results indicated that the BDPO can balance the unstable colloidal structure and restore the physical-rheological properties of aged asphalt binders, whose optimal dosages were determined as 1.5%, 3%, and 8% for the selected asphalt binder aged under RTFO, PAV, and UV aging conditions, respectively. Compared with commercial rejuvenating agents, the BDPO-rejuvenated asphalt exhibits performance properties similar to those of unaged asphalt in terms of high-temperature rutting resistance, fatigue cracking resistance, and low-temperature cracking resistance. FTIR spectra identified that the rejuvenation process of aged asphalt binders using BDPO involves complicated chemical reactions, which are beneficial to alleviate the aging degrees. These findings confirm the potential of BDPO as a promising rejuvenator for recycled asphalt pavements.