Characterization of binder and mix properties to detect reclaimed asphalt pavement content in bituminous mixtures

The purpose of this study was to recommend a testing procedure to detect the content of reclaimed asphalt pavement (RAP) used in hot-mix asphalt Mixtures. Asphalt was extracted from RAP for use in blending with new binder and aggregate. The recovered binders were blended with virgin asphalt (AC-10) at 10 different concentrations. A concept called relative energy loss was proposed to determine the engineering properties of recycled asphalt concrete (RAC). The relative energy loss was found to be directly related to the resistance of RAC to moisture-induced damage. A noticeable increase in relative energy loss with as much as 50% RAP was observed. At 20% RAP, there was not enough RAP to change binder or mixture properties. The predicted performance of mixtures containing up to 40% RAP by weight was shown to be similar to that of virgin material mixtures. A model was developed to estimate the RAP content in terms of penetration, viscosity, and relative energy loss.