Investigation of Reclaimed Asphalt Pavement blending efficiency through GPC and FTIR

• Reclaimed Asphalt Pavement and virgin asphalt blending efficiency are evaluated.
• Staged extraction method is implemented to evaluate blending in layered system.
• GPC and FTIR used to study staged extraction layers.
• Found blending does occur in all layers to different degrees.
• GPC and FTIR testing results support each methods findings.

Due to economical and environmental considerations, Reclaimed Asphalt Pavement (RAP) has been frequently included into asphalt paving mixtures during pavement construction and maintenance activities. Many studies have been conducted with regard to the effect of RAP inclusion in the pavement structure and its mechanical performance, yet the blending efficiency of the RAP and virgin binder is still unknown. It is often assumed that a complete blend between the RAP binder and virgin binder does occur. However, if there is not a complete blend concerns arise that the long-term pavement life could be compromised. In this study, staged extraction is performed on an asphalt mixture blend on the premise that individual layers of asphalt binder can be removed from the mixture until all that remains is the aggregate. Each binder layer is then tested and compared quantitatively using Gel Permeation Chromatography (GPC) and Fourier Transform Infrared Spectroscopy (FTIR) to identify the extent to which RAP and virgin binder blend. Results of this study have shown that a certain degree of blending does occur throughout all layers of the mixture.