Evaluation of Using Vacuum Oven for Residue Recovery of Asphalt Emulsion and Cutback Asphalt for Routine Screening

Asphalt emulsions and cutbacks are mainly used for surface preservation treatments and as bonding layer during pavement construction. Cutback and emulsion residues are routinely evaluated to ensure specification compliance for quality control and assurance purposes. The current test methods for residue recovery of asphalt emulsions and cutbacks are resource intensive, have a low throughput, and require distillation apparatus with a large lab footprint. This study developed two separate test methods that are simple and repeatable for emulsion and cutback residue recovery using a vacuum oven with the ultimate goal that these tests can be used for routine testing. These methods recover small quantity of the residue that is adequate to perform one test with 25 mm plate using dynamic shear rheometer (DSR). This study examines the repeatability of the new method by (1) using a variety of different grades obtained from different suppliers for both cutbacks and emulsions; and (2) participation of two laboratories with different brands of equipment. The mass loss during the residue recovery and the DSR parameter $G^{*}/\sin \delta$ were used to examine repeatability. The results show that the test methods developed are repeatable between the replicates and between the two participating research laboratories.