Diffusion and Rheological Properties of Asphalt Modified by Bio-Oil Regenerant Derived from Waste Wood

To decrease the usage of energy and improve waste recovery, dynamic simulations are conducted to understand the diffusion mechanism and rheological properties of bio-oil regenerated asphalt. A new simplified model of bio-oil modified asphalt (BMA) is built to calculate diffusion coefficients, diffusion driving force, viscosity, solubility parameters, and ductility. The calculated diffusion coefficients of bio-oil, asphaltenes, saturates, and resins are 4.5x10-3cm2/s, 3.6x10-4cm2/s, 4.2x10-4cm2/s, and 5.1x10-4cm2/s at 298 K, respectively. Results indicate that the bio-oil diffuses faster than asphaltenes, saturates, and resins, and that it can increase the ductility of asphalt and improve asphalt's elastic property. Moreover, potential energy is the key driving force of diffusion. There is no chemical reaction involved in the diffusion process of BMA and bio-oil can both reduce the viscosity of asphalt and soften it.