Deicer Impacts on Pavement Materials: Introduction and Recent Developments

A review of the impacts of deicers used in winter maintenance practices of Portland cement concrete and asphalt concrete roadways and airport pavements is presented. Traditional and relatively new deicers are incorporated in this review, including sodium chloride, magnesium chloride, calcium chloride, calcium magnesium acetate, potassium acetate, potassium formate, sodium acetate, and sodium formate. The detrimental effects of deicers on Portland cement concrete exist through three main pathways: 1) physical deterioration such as “salt scaling”; 2) chemical reactions between deicers and cement paste (a cation-oriented process, especially in the presence of magnesium chloride and calcium chloride); and 3) deicers aggrevating aggregate-cement reactions (such as the anion-oriented process in the case of chlorides, acetates, and formates affecting alkali-silica reactivity and the cation-oriented process in the case of calcium chloride and magnesium chloride affecting alkali-carbonate reactivity). The deicer impacts on asphalt concrete pavements had been relatively mild until acetateand formate-based deicers were introduced in recent years. The damaging mechanism seems to be a combination of chemical reactions, emulsifications and distillations, as well as the generation of additional stress in the