Freeze-thaw damage and chemical change of a portland cement concrete in the presence of diluted deicers

The present study experimentally investigates the effect of different diluted deicers on concrete deterioration. Laboratory simulations of environmental freeze/thaw cycling were first conducted on Portland cement concrete specimens in the presence of various deicers (NaCl, K-formate, NaCl-based deicer, K-acetate-based deicer, Na-acetate/Na-formate blend deicer, CMA deicer, or MgCl2 liquid deicer); and SEM/EDX measurements were then conducted for the concrete samples. Under the experimental conditions in this study, the CMA solid deicer and the MgCl2 liquid deicer were benign to the concrete durability, whereas K-formate and the Na-acetate/Na-formate blend deicer showed moderate amount of weight loss and noticeable deterioration of the concrete. NaCl, the NaCl-based deicer, and the K-acetate-based deicer were the most deleterious to the concrete. In addition to exacerbating physical distresses, each investigated chemical or diluted deicer chemically reacted with some of the cement hydrates and formed new products in the pores and cracks. Such physiochemical changes of the cement paste induced by the deicers pose various levels of risks for the concrete durability.