Investigation of mixing effect and molecular aggregation between virgin and aged asphalt

Abstract

The mixing process of virgin and aged asphalts is the essential of the rejuvenation of recycled asphalt pavement. The molecular association of asphalt may be decomposed and reconstructed due to the intermolecular interactions while virgin and aged asphalts are blended together. This study investigated the mixing effect between virgin and aged asphalts use rotational viscometer (RV), gel permeation chromatography (GPC) and molecular simulation methods. The high temperature viscosity of the mixed binder was tested by RV, which indicates that the viscosity of the mixed binder was not a linear superposition of virgin and aged asphalt. The GPC was used to test molecular weight of virgin, aged and mixed binders. The comparison between tested and calculated GPC curves shows that the molecular weight of the mixed binder was not the superimposed of virgin and aged asphalts. The molecular simulation indicates that the asphaltene and resin molecules had a tendency of gathering together. The mixing of two asphalt binders with different chemical structures could narrow the distance between aggregated molecules.