ABSTRACT
ABSTRACT: Two chemically and physically different SHRP asphalts (AAA-1 and AAC-1) were mixed with 15 and 50 percent of extracted RAP binders, designated Manitoba and South Carolina. Several analytical techniques including dynamic shear rheometry, Automated Flocculation Titrimetry (AFT), and Differential Scanning Calorimetry (DSC) were used to characterize physical properties of the starting materials and RAP binder mixtures. Results indicate that different virgin binders interact differently with different RAP binders suggesting that PG grade adjustment is both asphalt and RAP binder dependent where certain virgin binders require higher PG grade adjustment compared to other blends. This finding is somewhat contradictory to what current literature recommends. Results obtained in the present study seem to suggest that knowledge of the stiffness of starting materials alone does not adequately explain observed differences in PG grade change. Rather, information of the composition, specifically asphaltene content, lends additional insight into observed differences in PG grades of virgin with RAP binder mixtures.
