High-temperature rheological properties of lignin modified asphalt binder

This study aims to introduce lignin as a bio-additive to modify the base asphalt and investigate the high-temperature rheological properties of lignin modified asphalts and virgin asphalt. In this study, asphalt PG 58-28 was selected as the virgin asphalt, and four contents, 2%, 4%, 6% and 8%, of the total binder by weight of lignin were incorporated in the base binder. Rotational viscosity, dynamic shear rheometer, and multiple stress creep recovery tests were conducted to characterize the rheological performances of different types of asphalts. The results showed that the incorporation of lignin increased the viscosity of virgin asphalt at different rotational speeds. The activation energy showed an increasing trend as the lignin increased compared with the virgin asphalt. Meanwhile, the lignin incorporated into the asphalt binder increased the elastic components, and improved the resistance of asphalt binder to the permanent deformation regardless of the lignin contents. The addition of lignin in the asphalt binder could retard oxidation reactions that occurred in the asphalt during the rolling thin film oven aging. This study could provide a prospective foundation for the utilization of lignin extracted from waste biomass as an exceptional and renewable bio-additive in the field of asphalt pavement engineeringPapers presented at the 40th International Southern African Transport Conference on 04 -08 July 202