Progress and Perspective of Bio-asphalt Preparation, Structural Characterization, and Rheological Properties

As a renewable resource that can replace petroleum asphalt, bio-asphalt has been extensively studied in the past decade. To further advance the utilization of bio-asphalt in road construction, the preparation, structural characterization, and rheological characteristics of bio-asphalt were reviewed. First, the production procedure of biomass pyrolysis and liquefaction for bio-oil generation was outlined. The impact of preparation parameters on the yield and optimal parameter selection for preparing bio-asphalt was analyzed. Second, the structural characterization methods of bio-oil and the effect of the bio-asphalt chemical structure on rheological properties were summarized. On the basis of the colloidal theory, the colloidal instability index is employed to assess the stability of the colloidal structure in bio-asphalt, and the influence of colloidal stability on rheological properties was further analyzed. The research progress of the molecular dynamics method on the rheological characteristics of bio-asphalt was reviewed, and the influence of the intermolecular force of the bio-asphalt system on the aggregation and diffusion behavior of asphaltene clusters was expounded. Finally, a method of simulating heavy oil by using mesoscopic dynamics was summarized, and the feasibility of simulating the rheological behavior of bio-asphalt by mesoscopic dynamics was pointed out.