Evaluation of Rheological and Microscopic Properties of SBS-Modified Asphalt Binder with Multiple Regeneration

Styrene-butadiene-styrene (SBS) modified asphalt binder after aging seriously affects the performance of the road. In this study, waste edible oil, SBS modifier, plasticizer and antiaging agent were used to prepare a new regenerant to achieve the effect of regeneration of aged SBS modified asphalt binder. The type and optimum dosage of regenerant were determined by conventional performance test of asphalt binder. Dynamic shear rheology (DSR), bending beam rheology (BBR), Fourier transform infrared (FTIR), and gel permeation chromatography (GPC) were conducted to study the effects of regenerant on the rheological and microscopic properties of SBS modified asphalt binder with different aging degrees. The results show that the B-type regenerant has the best recovery effect on the aged asphalt binder. The optimum regenerant content corresponding to PAV10h, PAV20h, and PAV30h is 6wt%, 8wt%, and 10wt%, respectively. With the increase of aging degree, phase angle (delta) and creep rate (m) of SBS modified asphalt binder decreased, complex shear modulus (G*), rutting factor (G*/sin delta), and creep stiffness (s) increased. Besides, sulfoxide index (SI), carbonyl index (CI), large molecular weight (LMS) increased, and butadiene index (BI), and small molecular weight (SMS) decreased. When the regenerant is added, the rheological index and microindex content of the recycled SBS modified asphalt binder are opposite to those of the aged asphalt binder. In addition, microscopic analyses showed that the SBS modifier in the regenerant could reinteract with the asphalt binder and adjust the composition of the aged asphalt binder. Therefore, this study provides a new reference for realizing the regeneration of aged SBS modified asphalt binder, whereas the regenerated asphalt binder can be considered to be added to the asphalt mix to study the actual road performance.