SBS;  modified bitumen;  crosslinking;  Gel permeation chromatography

In order to study the crosslinking structure and stability of SBS in modified asphalt. The transformation process of SBS crosslinked structure was studied by gel permeation chromatography (GPC) and compared with the fluorescence microscopy results. The results showed that the GPC analysis conclusion was consistent with fluorescence microscopy, which proved that it could effectively characterize the SBS crosslinked structure. During the processing of modified asphalt, the average molecular weight of SBS increased to form a cross-linked structure, and SBS species and asphalt species had different degrees of influence on the crosslinking of SBS. A small amount of SBS cross-linked structure was degraded after the rotating film oven aging test (RTFOT), but it still had a good modification effect on asphalt.