Rheological behavior of Japanese cedar-based biobinder as partial replacement for bituminous binder

Currently, road and airport pavement construction uses approximately 90% asphalt, most of which is mainly derived from fossil fuels. However, with the improvement in oil refinery technology, the quality of asphalt binders is degrading gradually. Moreover, from the environment standpoint, fossil fuels are the main source of greenhouse gases, which lead to global warming. Consequently, there is an urgent need to develop a more sustainable binding material from renewable or other alternative resources to replace or modify the existing petroleum-based asphalt binder for the highway industry. The main objective of this study was to investigate the potential use of a bio-oil byproduct as a partial replacement for a bitumen-based binder. The properties of various blending combinations of a biobinder and asphalt binder were compared with those of an unmodified asphalt binder through several physical and rheological tests. The specific gravity of the biobinder was found to be higher than that of the petroleum-based binder. In general, biobinder blends have a higher viscosity than that of the unmodified binder at temperatures higher than 60°C. Binders containing the biobinder at 25% and 50% have lower temperature susceptibility than that of the unmodified binder. Adding the biobinder at up to 25% does not significantly change the complex shear modulus of unaged binders, whereas rolling thin-film oven-aged biobinder blends show a higher complex modulus and greater viscosity than those of the unmodified binder. Moreover, the biobinder blends show higher G^∗sin δ, lower nonrecoverable compliance and greater recovery ability than those of conventional AC-20.