Use of Hansen Solubility Parameters (HSP) in the selection of highly effective rejuvenators for aged bitumen

While there is considerable research regarding the recycling and reuse of aged bitumen in terms of the evaluation of rheological properties, there is not much fundamental understanding regarding the underlying mechanisms of the rejuvenation process. Specifically, the rationale behind rejuvenator selection and the efficiency of rejuvenators is not well understood. This paper proposes an approach for rejuvenator selection based on Hansen Solubility Parameters (HSP). To fully validate its feasibility, rheological and chemical tests were also performed. The results revealed that highly efficient rejuvenators have similar HSP with bitumen and greater HSP radii. The overlapping ratio between the Hansen spheres of bitumen and rejuvenators could be considered as a reliable tool to screen rejuvenators. Linear correlations were found between the efficiency of rejuvenators and solubility spheres. The rheological and chemical tests using master curve analysis and saturates, aromatics, resins and asphaltenes (SARA) fractionation further supported using HSP as a basis for rejuvenator selection.