Influence of aging on thermal behavior and characterization of SBR compound-modified asphalt

Sulfur and polyphosphoric acid (PPA) were used to improve the thermal stability and high-temperature property of styrene–butadiene rubber (SBR)-modified asphalt before and after short-term and long-term aging. The physical, rheological properties, and thermal behavior of asphalt binders were studied. The study showed that the addition of PPA improved the thermal stability and high-temperature property of SBR-modified asphalt evidently, and the improved property caused by the gelation effect of PPA was not influenced by aging further. Though sulfur also improved thermal stability and high-temperature property of SBR-modified asphalt before aging, the improved properties declined evidently with further aging, due to the susceptibility of SBR/sulfur-modified asphalt to aging. It is reasonable to assume that the SBR-modified asphalt could be improved further only by the addition of PPA. In the study of polymer-modified asphalts, thermodynamic analysis can reflect the structural characteristics of asphalt binders before and after aging efficiently and confirms the conclusions of physical and rheological testings to some extent.