Alternatives to Chlorides for De-icing
Research Idea Scope
Many DOTs across the country apply salt (estimated at 22 million tons annually in the US) during the winter to lower the freezing point and accelerating the melting process. Unfortunately, salt is highly soluble, splitting into sodium and chloride ions and entering surface waters. Studies are showing receiving waters, particularly in the northeast, have increased salt concentrations, adversely affecting water quality and impacting aquatic biota. Regulatory concern and, in cases restrictions, have therefore increased. Departments of Transportation are investigating ways to reduce salt use. The purpose of this synthesis topic is to survey the alternatives that are currently in use as alternatives to salt, and provide information relative to their cost and effectiveness.
Urgency and Payoff
There are a variety of alternatives in practice including sand, beet juice, molasses, cheese brine, and synthetic deicers. Each of these products have distinctive characteristics that affect the effective range of temperature, application techniques, storage, costs and environmental impacts. Assembling this information in a single document that facilitates comparison of the practice-ready options for deicing is of high value to DOTs. The last previous NCHRP synthesis on this topic was published in 1974. NCHRP Synthesis 449 published in 2013 presents information on identified proactive strategies used to mitigate the impacts of chloride road deicers on the natural environment. That is distinctly different from identifying alternatives to the use of chlorides, the subject of this synthesis. NCHRP 577 develops a decision tool for specifying deicers, which will serve as an excellent complement to this synthesis.
Becky Humphreys AFB65 6143871125