Using bio-based rejuvenator derived from waste wood to recycle old asphalt

The objective of this study is to investigate the possibility of using bio-oil derived from waste wood as a rejuvenator to recycle aged asphalt binders. In this study, petroleum asphalt of PG58-28 was selected as the base binder. The bio-oil rejuvenators with concentrations of 10%, 15% and 20% by weight were added into the Pressure Aging Vessel (PAV) aged base binder to prepare the bio-rejuvenated asphalts. Through the chemical compounds analysis of the bio-oil using the Gas Chromatograph Mass Spectrometer (GC-MS) test, it can be found that the bio-oil derived from waste wood contains a high content of light compounds, including phenol, naphthalene, diethyl phthalate and so on. The rheological properties of bio-rejuvenated asphalts were evaluated and compared with the virgin and aged asphalts by Rotational Viscometer (RV), Dynamic Shear Rheometer (DSR) and Bending Beam Rheometer (BBR) tests. The bio-rejuvenator can increase the viscous components and alleviate the stiffness of the aged asphalt binder. The high content of light compounds in the bio-oil balanced the chemical compounds of the aged asphalt. As a result, the rutting resistance and fatigue resistance of the aged asphalt binder were restored by the bio-oil significantly. The low temperature crack resistance of aged asphalt binder can be restored to approximately to that of the PG 58-28 by the bio-rejuvenator with the concentration of 15% and 20%. The bio-oil concentration had less impact on the rheological properties of bio-rejuvenated asphalts when the bio-oil concentration was higher than 15%. Therefore, the bio-oil with a concentration of 15% was recommended to rejuvenate the aged asphalt binder to be reused in the construction of pavement.