Bulk Specific Gravity of Reclaimed Asphalt Pavement Aggregate

Abstract

Several methods are available for determining the bulk specific gravity (Gsb) of reclaimed asphalt pavement (RAP). However, a clear recommendation has not been had for determining this property. In this study, asphalt mixes with known aggregate properties were produced and aged in the laboratory to simulate RAP. The aggregates were recovered, and the aggregate properties, including Gsb, were reassessed. The aged mixtures were also tested to determine maximum theoretical specific gravity (Gmm), from which estimated Gsb values could be calculated. The Gsb values from both the extraction and Gmm methods were compared with the known or true Gsb values for these aggregates. The effects of the RAP Gsb errors on voids in mineral aggregate values from the various methods were also evaluated. On the basis of the results of this study, it is recommended that the Gmm method be used to determine the RAP Gsb when a regional absorption value is known.