Evaluation on recycling effect of a novel rejuvenator combined with fresh asphalt on field-aged SBS modified asphalt by rheological and micro characteristics

Styrene-butadiene-styrene block copolymers (SBS) modified asphalt has been the main binder applied in the surface course of high-grade asphalt pavement. However, as more and more pavements are entering into the maintenance period, a mass of waste SBS modified asphalt mixtures are produced. To effectively restore the performance of field-aged SBS modified asphalt (SBSMA), a novel rejuvenator (RA) combined with fresh SBSMA was used in this research. The rheological properties of recycled SBSMA were investigated using dynamic shear and bending beam rheometer tests, and the micro characteristics were characterized by fluorescence microscopy, Fourier transforms infrared spectroscopy and chemical composition tests. The results indicate that RA can lessen the aging behavior of recycled SBSMA from the molecular structure, enhance the compatibility between SBS modifier and asphalt in recycled SBSMA. The combined utilization of RA and new SBSMA can effectively recover the high, intermediate and low temperature rheological properties of recycled SBSMA. Moreover, when the ratio of aged SBSMA with RA to new SBSMA is 0.45:1, the recycled SBSMA has the closest continuous performance grade to new SBSMA.