| Description |
This research was an effort to create and test a performance-based mix design that allows for oil sand to be incorporated as the binder material. The design is based on creating an open-graded aggregate blend that will allow incorporating the optimum volume of oil sand. The oil sand used in this project is a natural, unmodified material that was characterized to explore its unique attributes. Aggregate stockpiles were blended to find the maximum space for the oil sand to be added in the mix. A field project was performed to bring the laboratory mix to full-size scale. Even though there were some minor delays while trying to incorporate the oil sand into the mixing chain, the results prove that the design from this work was feasible. Loose mix samples were obtained and brought back to the laboratory for testing. The Hamburg Wheel Tracking Device (HWTD), Bending Beam Rheometer (BBR), and Asphalt Mixture Performance Tester (AMPT) were performed on the loose mix samples from the field project. The results were compared with the laboratory mix results as well as with results from conventional hot mix asphalt (HMA) mixes used in Utah. The HWTD shows the mix has a solid aggregate structure; however, there is a potential for premature pavement failure due to moisture susceptibility. In the BBR, all of the oil sand mixes had a iv greater creep stiffness at low temperatures than conventional binder grades; meaning that the oil sand mixtures are more likely to crack at low in-service temperatures when compared to the performance binders typically used in interstate roads. In the AMPT, at high in-service temperatures, the dynamic modulus was lower than the conventional mixes, meaning there is a greater likelihood of rutting occurring at high temperatures because the binding material is softer. Based on these performance measures, it was determined that it is possible to develop a mixture that incorporates oil sands into a pavement material for rural or low volume roads. There are economic and environmental advantages to using oil sand mixes as a roadway material. Oil sand mixes require a lower mixing temperature than HMA and, therefore, can save on both fuel costs and emissions. |
