Incorporation of Jordanian oil shale in hot mix asphalt

Many projects utilizing oil shale for power generation and shale oil extraction are being investigated, developed, or built due to an increase interest in utilizing this source of energy. It is expected that this evolving industry will produce large quantities of oil shale waste particles having very fine sizes which are considered both harmful to the environment and a loss of a valuable resource. This investigation is considering to address both of these two negative expectations by incorporating the above fine oil shale particles into hot mix asphalt (HMA) pavement formulations. Different compositions of oil shale in the new asphalt pavement mixtures were investigated in accordance of local highway regulations. The results of this work are very promising. For example, Marshall stability showed an improvement by 10–20%. All required properties by Jordanian highway regulations (which are, in general, based on American Association of State Highway and Transportation Officials, AASHTO) such as flow, voids in mineral aggregates and air voids have been either satisfied or even improved. In addition, resilient modulus, creep and fatigue tests were performed on some formulations. The major findings of these tests indicate that HMA containing only limestone is more resistant to rutting in the short run however; it loses its strength as it ages. On the other hand, HMA containing oil shale is not as much resistant to rutting in the short run; however, it retains its flexibility in the long run (more fatigue resistance). Finally, the environmental investigation of the impact of using oil shale in HMA pavements indicates that there are no negative impacts on the environment with respect to leaching and radioactivity.