Validation of Reclaimed Shingles Asphalt Binder Extraction and Recovery Methods

Abstract

For cost savings and environmental benefits, recycled materials known as recycled asphalt pavement (RAP) and recycled asphalt shingles (RAS) have been widely used by the asphalt paving industry in recent years. To maximize the benefit of using RAS, the properties of the recycled materials, especially the asphalt binder properties, should be characterized before the mix design. In most cases, the solvent-based asphalt binder extraction and recovery is unavoidable for binder characterization. However, most of the RAS binder is very stiff, which raises concerns about the asphalt binder recovery method, for example, whether or not the solvent is left in the recovered asphalt binder and if the recovered asphalt binder is stiffened due to over-cooking for removing the solvent. In this paper, the authors compared both rheological properties and chemical components of the original binder before recovery with the same binder after recovery. The rheological properties of the asphalt binder were evaluated using the dynamic shear rheometer (DSR) and the bending beam rheometer (BBR), and its chemical property was measured with Fourier transform infrared spectroscopy (FTIR). The results indicate that the extraction and recovery process did not change properties of the RAS binder. Therefore, the asphalt extraction and recovery process are valid for the RAS asphalt binder evaluation.