, Former Senior Research Prgrm Mngr, UMD-NRRI
This project demonstrated the use of either crushed Minnesota taconite crude ore or coarse (wet or dry) cobber concentrate as an aggregate material in road formulations. The use of such an aggregate provides enhanced absorption of microwaves and conversion to heat. In laboratory tests at NRRI, it has been found that use of taconite can give a tenfold increase in microwave absorption. This in turn has many potential benefits, including roadways with enhanced ability to remove ice and snow, and a uniquely effective all-season pothole patching technology. In laboratory simulations the authors have shown that, when microwaves are applied to a roadway with a coating of ice, the microwaves pass through the ice and are absorbed at the road-ice interface, allowing the ice to be scraped away to provide a dry roadway without use of chemicals. Although the authors expected this technology to be applied originally to special applications such as bridge decks and airport runways, eventual application to multilane highways would provide a significant market for taconite rock, on the order of 10,000 tons per mile. This report summarizes the completed work, including a large number of equations characterizing key parameters and an extensive list of references.