Project Summary

Asphalt material producers sometimes incorporate Recycled Engine Oil Bottoms (REOB) into paving asphalt in order to alter its performance grade (PG). State Departments of Transportation express concern that REOB decreases pavement lifetime, even though it does not violate the specifications that are intended to ensure good performance. This research project assesses REOB in asphalt through two complementary approaches: (1) experimental measurements to detect presence of REOB in asphalt binders used in Rhode Island, and (2) molecular simulations to quantify mechanisms about how REOB alters asphalt mechanics, meaning viscosity and complex modulus G*. Prior work at URI has indicated that Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) can identify REOB presence while simultaneously suggesting a metalbased fingerprint of asphalt chemistry. Other prior work at URI has developed nanoscale model systems that replicate asphalt properties within molecular dynamics simulations. In this project, the intent of approach (1) is to provide ICP-MS experimental data that complement simultaneous development at RIDOT of a REOB detection approach based on X-ray fluorescence (XRF). The intent of approach (2) is to identify rheological distinctions to anticipate between systems with and without REOB. Such perspectives can then be applied toward interpreting effects of REOB on measured asphalt DSR data and can guide rheology studies in future work.