Alternative solvent for reducing health and environmental hazards in extracting asphalt - An evaluation

Trichloroethylene is a solvent currently used by the Florida Department of Transportation (FDOT) and many state highway agencies for separation of asphalt binders from asphalt paving mixtures in their quality control programs. However, it has been proved that trichloroethylene contributes to ozone depletion, and it is also known to be a carcinogen. The goal of the present study was to determine whether a more environmentally sound and less hazardous solvent could be used for this purpose. The solvent investigated is an n-propyl bromide with the trade name EnSolv. Preliminary studies show that it is safer than many other solvents available today. The study was performed to determine whether EnSolv could be a substitute for trichloroethylene without changing current testing methods. The tests performed included the asphalt solubility test, extraction and recovery of asphalt binders from mixtures, and penetration and viscosity tests with the recovered binders. The results of the study showed that EnSolv could be a suitable replacement for trichloroethylene. In addition, EnSolv could also be recycled and reused in the extraction and recovery procedures.