Use of Prewetted Solid Materials for Roadway Anti-Icing: Synthesis Report

US Transportation Collection2018PDFTech ReportCTC & Associates LLCMinnesota. Dept. of Transportation. Clear Roads Pooled FundMinnesota. Department of Transportation. Clear Roads Pooled FundUnited StatesAnti-icingBrinesHighway maintenanceSnow and ice controlSodium chlorideSolidsState departments of transportationWinter maintenanceCR 17-S2Final ReportAnti-icing (also known as \u201cpre-treating\u201d) is the winter road maintenance practice of applying a liquid or solid material intended to depress the freezing point of water in order to prevent winter storm precipitate from bonding to roadway pavement. Anti-icing may be performed hours (or even days) before a winter storm event begins; it can also be performed after ice or snow begins to fall in order to keep pavements as clear of ice and snow as possible. Salt [sodium chloride] brine and other chloride liquids are widely used for anti-icing. Historically, materials other than liquids, such as dry and prewetted salt/solids, have also been used by winter maintenance agencies for anti-icing. This Clear Roads synthesis project sought to learn how and the extent to which agencies use prewetted salts/solids for anti-icing, the conditions under which they are used, their effectiveness, cost-effectiveness and agencies\u2019 response to environmental concerns about anti-icing salt use. The investigation included a national survey of state department of transportation winter maintenance experts that gathered information about materials used for anti-icing, including reasons why materials were selected, how they were prepared and applied, and their effectiveness, with particular focus on the use of prewetted solids. The results of a literature search supplemented the survey findings.133