Federal Highway Administration (FHWA)
Anti-icing; Calcium chloride; Concrete pavements; Deicing chemicals; Deterioration; Freeze thaw durability; Magnesium chloride; Mitigation strategies; Highways; Pavements
This Tech Brief focuses on a recently recognized form of deterioration on concrete pavements referred to as chemical deicer distress. It is gaining attention due to the increased frequency and severity of its appearance, which is related to the increased use of aqueous solutions of calcium chloride (CaCl₂) and magnesium chloride (MgCl₂) for pavement deicing (Sutter et al. 2008; Weiss and Farnam 2015). The resulting pavement distress often first appears as a “shadowing” at the pavement joints, which progresses into disintegration of the concrete (Taylor, Sutter, and Weiss 2012). This Tech Brief summarizes the use of chemical anti-icers and deicers, reviews how hydraulic cement paste (HCP) is traditionally protected from freeze-thaw damage, describes physical and chemical distress mechanisms in the presence of aqueous CaCl₂ or MgCl₂ brine solutions, and discusses strategies that can be employed to mitigate this distress.