Construction aggregate potential of minnesota taconite industry byproducts

Every year, mining and processing of Minnesota taconite (iron ore) generates about 125 million tons of byproducts, a figure that is about double the entire state's annual construction aggregate output and usage. Since the year 2000, the Natural Resources Research Institute (NRRI), University of Minnesota Duluth, has been investigating how these vast quantities of byproducts can be used for construction aggregate purposes. The NRRI has been leading a comprehensive research and demonstration program that is designed to: 1) identify new environmentally responsible and economically viable uses for Minnesota Iron Range taconite aggregate material in road construction, road repair, and other applications where crushed stone aggregate is needed; and 2) conduct demonstration projects inside and outside Minnesota. This paper presents a broad overview of the 2006-2009 research program within the context of resource sustainability, energy conservation, and infrastructure benefits. Highlighted research concepts, activities, and results related to cold climate applications include: cold-temperature testing of taconite-based hot-mix asphalt (HMA) mix designs; chemical-free deicing and all-season pothole repair using microwave technology; the development of asphalt- and cement-free pothole repair and patching compounds; and field demonstration projects that use taconite aggregates as an integral road and/or pavement component, such as in high-friction/anti-skid bridge deck surfacing treatments. Copyright ASCE 2009.