PHYSICAL AND ENVIRONMENTAL PROPERTIES OF ASPHALT-AMENDED BOTTOM ASH

A 2-year study is under way to evaluate the physical and chemical properties of the bottom ash process stream from the 500 tons/day waste-to-energy facility in Concord, New Hampshire. The use of bottom ash as an aggregate substitute product in asphaltic base course is envisioned. Research is under way to characterize the time-dependent properties of the bottom ash for product acceptance, to develop asphalt concrete mixes with varied percentages of bottom ash, and to evaluate the leachate release rate characteristics from various asphalt blends using a variety of batch and lysimeter leach tests. Results to date suggest that the bottom ash product stream is relatively constant, hot mix formulations meet New Hampshire Department of Transportation specifications, and bitumen is effective in encapsulating bottom ash and reducing salt leachability.