Development of sustainable compound bio-oil rejuvenator and its rejuvenation mechanism on long-term aged asphalt

Abstract

To develop a new sustainable compound bio-oil rejuvenator product and understand its rejuvenation mechanism on long-term aged asphalt, the castor oil vegetable asphalt (COA) was selected to react with epoxidized soybean oil (ESO) for preparing the compound bio-oil rejuvenator of long-term aged asphalt. The in-situ dynamic chemical reactions between COA and ESO, as well as the changes in basic properties, chemical compositions, molecular weight distributions and microstructures of aged asphalt were characterized before and after rejuvenation. Results indicate that COA and ESO undergo ring-opening reactions at 80 °C. These reactions still occur continuously during the rejuvenation process of aged asphalt. The compound bio-oil recovers the physical performance of long-term aged asphalt to its original level before aging. Under the combined action of COA and ESO, the sulfoxide index and carbonyl index of long-term aged asphalt samples are decreased. Molecular weight distribution of aged asphalt can be recovered with compound bio-oil. The lengths of catana phases of long-term aged base asphalt and SBS modified asphalt can be restored to their original lengths respectively. Although the average surface roughness of long-term aged base asphalt and SBS modified asphalt can be restored to the original level of base asphalt and SBS modified asphalt, it is difficult to accurately characterize the degree of asphalt rejuvenation due to the uncertainty of its changes. The developed compound bio-oil rejuvenator is suitable to restore the pavement properties of long-term aged asphalt. This is socially beneficial, economically viable and environmentally imperative.