New apparatus and procedure for the extraction and recovery of asphalt binder from pavement mixtures

A new apparatus and procedure for the purpose of extracting asphalt binder from hot-mix and pavement samples has been developed. This procedure is the culmination of previous reports on solvents for the extraction of asphalt, the aging of asphalt in solution, and the removal of solvent from asphalt. The apparatus consists of a rotary drum for the purpose of efficient and thorough contacting of the aggregate-binder sample with the solvent, followed by filtration and then solvent removal using a Roto-vap procedure. Intralaboratory tests of the procedure on a variety of samples indicate that the precision associated with one standard deviation is about 6 percent for extracted asphalt viscosities. This compares with interlaboratory precision of about 30 percent for previous methods according to the AASHTO Materials Reference Laboratory proficiency sample program. Additionally, this new procedure provides recovered asphalt that has physical properties, such as viscosity, that are much closer to the 'true' physical properties of the binder as it existed in the pavement. This is essential if tests performed on the binder are to have any meaning with respect to pavement performance.

New apparatus and procedure for the extraction and recovery of asphalt binder from pavement mixtures Report