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

A real rejuvenator must have the ability to disaggregate oxidized asphaltene nanoclusters. However, few studies pay attention to the topic, and there is a lack of comparison of the disaggregation ability of different rejuvenators. Thus, the disaggregation ability and regeneration mechanism of three bio-rejuvenators (waste cooking oil (WCO), waste wood oil (WWO), and straw liquefied residue oil (SLRO)) on oxidized asphaltene nanoclusters were studied in this paper. Laboratory tests and molecular dynamics (MD) simulation were used to compare the effectiveness of the three bio-rejuvenators and reveal its corresponding mechanism. It is found that these bio-rejuvenators have a softening effect on aged asphalt binder, but not all of them can disaggregate oxidized asphaltene nanoclusters. The introduction of WWO and WCO can effectively disturb the nanoclusters caused by the increase of polar functional groups during the oxidation process. The effect of WWO is more significant, but neither of them can restore the asphaltene dispersion to the virgin asphalt binder. SLRO has an adverse effect on the disaggregation of oxidized asphaltene nanoclusters. WCO, WWO, and SLRO showed different disaggregation mechanisms, including ″pull-out, intercalation, and compression″, respectively. WCO and WWO can increase the activation energy reduced by aging in a short aging time, and SLRO makes the activation energy lower. Such findings can help enterprises screen more reasonable rejuvenators to facilitate the recycling of reclaimed asphalt pavement (RAP) materials and promote the sustainable development of the construction industry.