Road Management & Engineering Journal
February 2, 1998
(U.S. and Canada)
Fax: (360) 335-6402
|(This article is reproduced with permission from "On the Move: The Direction in Transportation Progress," the newsletter of the Utah Technology Transfer Center. The article appeared in the Spring (March) 1997 edition, Volume 10, Number 1.)|
UDOT [Utah Department of Transportation] maintains 105 salt stockpiles throughout the state. Approximately 50% of these sites use some type of detention system to catch water runoff from the stockpiles. In environmentally sensitive areas, UDOT uses salt detention basins constructed of dense graded asphalt mixes with zero air voids. Recently, the Utah Department of Environmental Quality (DEQ) raised concerns about the intrusion of salt into the ground water thus possibly affecting the drinking water. In an effort to address this concern, UDOT collaborated with the Utah Water Research Laboratory (UWRL) at Utah State University to evaluate their salt detention basins.
Core samples were taken from UDOT's sealed, zero air void asphalt liners and tested in accordance with the EPA's specified test procedures. The results of this testing indicate that the permeability values were lower than those required by EPA for landfill liners.
As a result of this study, UDOT is planning to use the dense grated, zero air void asphalt mix in all of their salt detention basins to ensure negligible salt intrusion into the underlying ground water. Extreme care and close quality control, however, must be exercised in the construction and maintenance of the asphalt liners to prevent cracks from developing. Care must be taken during use so that the asphalt liners will not be punctured or broken and must be properly maintained.