Towards an understanding of diffusion mechanism of bio-rejuvenators in aged asphalt binder through molecular dynamics simulation

Research on the Ability of Bio-rejuvenators to Disaggregate Oxidized Asphaltene Nanoclusters in Aged Asphalt

“…Oxidized asphaltenes mainly have the following stacking structures: face-to-face stacking, offset face-to-face stacking, T-shaped stacking, and other aggregation phenomena, which are basically consistent with the previous research conclusions. 29 , 41 , 43 , 54 It is reported that aging increases the polar functional groups, which increases the strength of mutual attraction between molecules and shortens the distance between PAH structures and makes it easier to stack.…”

“…More oxygen and sulfur atoms were added to the long-term aged asphalt compared to the virgin asphalt binder. 29 The asphaltene molecule used in this study is the molecular structure published by Martín-Martínez et al, 39 which has a chemical structure with lower energy and thus provides a more stable and probable model for the asphaltene compared with the original molecule proposed by Li and Greenfield. 40 To develop the model, a system of 15 asphaltene pyrrole molecules shown as ″VirAsP″ and 15 oxidized asphaltenes 41 shown as ″OxAsP″ was separately built and optimized ( Figure 1 ).…”

“… 28 It is reported that swine manure was effective in restoring oxidized asphalt’s thermomechanical properties as amide groups in it interact with asphaltene molecules, increasing the stacking distance of asphaltene dimers while changing their conformational packing. 29 From this perspective, the current mainstream of bio-rejuvenators pays little attention to the investigation of disaggregating oxidized asphaltene nanoclusters. And few previous studies compare the disaggregation ability and rejuvenation mechanism of different bio-rejuvenators.…”

“…It is proved that the ability to properly dissolve and disperse macromolecules and microstructures in aged asphalt binder is the key to the durability and reaging resistance of recycled asphalt. , Actually, a true rejuvenator should be a kind of asphalt additive that can deagglomerate large asphaltene assemblies into smaller nanoaggregates while replenishing the lost compounds . It is reported that swine manure was effective in restoring oxidized asphalt’s thermomechanical properties as amide groups in it interact with asphaltene molecules, increasing the stacking distance of asphaltene dimers while changing their conformational packing . From this perspective, the current mainstream of bio-rejuvenators pays little attention to the investigation of disaggregating oxidized asphaltene nanoclusters.…”

A Molecular Dynamics Approach to the Impacts of Oxidative Aging on the Engineering Characteristics of Asphalt

“…Enhancement in the electrostatic attractiveness was attributed to the polar groups added onto the oxidized asphalt molecules, and its correlation was established with the improved hardness of the asphalt model, as noted in the simulated mechanical responses. The aging-induced stronger molecular interactions was also reflected through increase in density and cohesive energy density (CED), as well as reduced diffusion coefficient in a number of studies using different asphalt models [ 14 , 15 , 16 , 17 ].…”