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• The intermolecular interaction between virgin and aged asphalt. • The interaction affected the mixed binder performance. • The interaction degree was related to the chemical difference of binders. 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. [ABSTRACT FROM AUTHOR]

The recycling of asphalt shingles in pavement construction is beneficial to the environment and industry by reducing the consumption of virgin materials. However, current approaches of utilizing recycled asphalt shingle (RAS) by mixing with soft asphalt or rejuvenator were questionable for the anti-aging problems. This study developed a new approach to recycle asphalt shingles, in which the RAS binder was dissolved and extracted by a mixed solvent of heptane and trichloroethylene (TCE). In the proposed process, the viscosity of the extracted RAS binder was controlled by the polarity and composition of the mixed solvent. Results indicate that heptane dissolved the soft part and trichloroethylene (TCE) could dissolve the stiff part of RAS binder. The use of the mixed solvent of heptane and TCE with a certain proportion through the proposed method could prepare asphalt binder with desired properties. The current approaches of utilizing RAS were compared with the proposed method. Results indicate that the anti-aging properties of extracted RAS binder using the proposed method were better since the soft asphalt could not dissolve RAS binder at 170 °C, and the binder blend of RAS binder and rejuvenator had a potential anti-aging problem because an obvious loss of rejuvenator existed during the aging process. The performance test suggests that the high and low temperature region of the extracted RAS binder was close to 75.2–28 °C, which could be used as a common asphalt in pavement engineering. • RAS binder was extracted and used as common asphalt. • Heptane and TCE were mixed to prepare the mixed solvent. • Soft asphalt could not dissolve RAS binder. • Rejuvenator was evaporated seriously during the short aging process. [ABSTRACT FROM AUTHOR]