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Understanding and Mitigating the Effects of Chloride Deicer Exposure In Concrete

Started: August, 2011 Ended: March, 2014 Project ID #4W3719 Status: Completed

Objective

The objective of this project is to investigate the effects of chloride deicers on Oregon DOT and Alaska DOT&PF concrete bridge decks and to identify and evaluate best practices and products to mitigate such effects in the states of Oregon and Alaska.

Abstract

To maintain safe and productive roadways during the winter season, ODOT applies a magnesium chloride (MgCl2) solution for snow and ice control in accordance with guidelines established by the Pacific Northwest Snowfighters Association and others. The corrosive effect of chloride on embedded steel reinforcement is well known; however, it is unclear whether deicers based on chloride salts deteriorate concrete. Laboratory studies using concentrated solutions to accelerate testing have demonstrated that magnesium chloride has the potential to damage concrete. However, field cores extracted from sites in Colorado, Idaho, Iowa, Montana, and South Dakota did not exhibit damage conclusively attributable to deicers. Consequently, ODOT does not know the damaging effects that chloride deicers may impart on Oregon’s concrete infrastructure over time. The exposure to deicing chemicals at a specific site may depend not only on application frequency but also on other factors such as environmental and traffic conditions and bridge configuration. Deicer may be applied directly to a bridge deck or roadway, but other nearby concrete elements such as rails, barriers, and columns may be vulnerable due to splash. Consequently, not all bridges or concrete components (e.g., decks, beams/crossbeams, diaphragms, abutments, piers and piles) are expected to have the same likelihood of damage. However, there is no known practical means to measure deicer exposure in order to focus on those bridges or components potentially at highest risk. There is an urgent need for DOTs to identify and evaluate best practices and products for enhancing the strength and durability of concrete infrastructure in the presence of chloride deicers.

Contacts

Sponsors & Partners

  • Oregon Department of Transportation (ODOT) Sponsor
  • Alaska University Transportation Center (AUTC) Co-Sponsor

Part of: Winter Maintenance and Effects, UTC, UAF-CESTiCC

Project Tagged In: bridge decks, concrete materials, deicer impact

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