Evaluation of incorporating oil shale filler aggregate into hot mix asphalt using Superpave mix design

• Replacement of filler size limestone aggregate with oil shale is promising.
• The properties of modified HMA have either remained acceptable (not changed) or improved.
• Rutting and fatigue resistances for some tested compositions increased by around 50%.
• Incorporation of oil shale into HMA pavement has a positive overall economic potential.

The world is on the run looking for new energy resources, improvements and conservation on current energy resources while at the same time trying to keep the environment safe and clean, keeping in mind the economic constraints of all the above. Recycling and minimization of waste produced from the above activities are among top priorities for policy makers. Oil shale is on the rise as an additional source of energy. This sector of the industry has not yet reached maturity and still under development. One application of oil shale is the direct combustion, where fine oil shale is produced as a waste and considered an environmental hazard. This investigation proposed the incorporation of such filler size oil shale into hot mix asphalt (HMA). The study used Superpave design method. The study included resilient modulus, creep and fatigue measurements. The results showed a mixed performance where, depending on the HMA formulation, the inclusion of oil shale filler produced better performance than the control limestone filler whereas other formulations showed the contrary.

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