Deicer Impacts on Concrete Bridge Decks: A Comparative Study of Field Cores from Potassium Acetate and Sodium Chloride Environments

The use of chemical deicers in cold regions has raised concerns over their potential negative effects on the performance and durability of concrete infrastructure. Extensive studies have been conducted in the laboratory setting, often in an accelerated manner, which reported the chemical and physical deterioration of concrete as a function of deicer type. Yet, little research has been published on how the deterioration of concrete bridge decks in the field environment is affected by their exposure to deicers, where the durability of concrete is also affected by temperature cycles and mechanical loadings. This work reports a comparative study of field cores taken from two select Nebraska concrete decks and from two select Utah concrete decks. The Nebraska decks had been exposed to mainly potassium acetate (KAc) deicers, whereas the Utah decks had been exposed to mainly sodium chloride (NaCl) deicers. The field cores were tested for their mechanical properties and transport properties. They were also subjected to staining tests to detect possible chloride penetration, carbonation, and aggregate silica reaction (ASR), and subjected to petrographic analysis to characterize their paste and air contents. The concrete cores from Nebraska exhibited more significant degradation, relative to those from Utah. Specifically, the exposure to KAc deicer led to significant reduction in mechanical properties (compressive strength, splitting tensile strength, and microhardness) and more signs of ASR. This case study sheds some light on this complex issue of concrete durability and raises the awareness over the risk of using KAc deicers on concrete structures and components.