Investigation of deicing chemicals and their interactions with concrete materials

The interactions of concrete specimens (plain and with fly ash addition) with six different deicers was investigated by exposing them to solutions of sodium chloride (NaCl), magnesium chloride (MgCl2), calcium chloride (CaCl2), and the combinations of: sodium chloride with magnesium chloride (NaCl + MgCl2), sodium chloride with calcium chloride (NaCl + CaCl2), sodium chloride with agricultural product – Ice Ban® (NaCl + Ice Ban®). In addition, one group of specimens was exposed to the de-ionized water used as control solution. The exposures consisted of wet/dry (W/D) and freeze/thaw (F/T) condition cycles as well as control cycle (continuous exposure to lime water at room temperature (23°C)). The effects of the exposure were evaluated based on the changes in the dynamic modulus of elasticity, changes in mass and the amount of scaling. In addition, absorption and chloride penetration measurements were performed at room temperature of 23°C. The qualitative evaluation of the appearance of the samples was also performed. Among the deicer/anti-icers tested, calcium chloride and magnesium chloride caused the most damage. Although the deterioration of the specimens exposed to magnesium chloride was delayed with respect to specimens exposed to calcium chloride, the magnitude of the deterioration was comparable to that experienced by specimens exposed to calcium chloride. The best performance (least amount of damage) was observed for specimens exposed to sodium chloride solutions followed by the specimens exposed to the combination of sodium chloride with magnesium chloride and sodium chloride with calcium chloride. Results indicate that F/T exposure conditions are much more severe than W/D regimes, even though the concentrations of deicers/anti-icers used for F/T cycles were about 50% lower than those used for W/D cycles. Moreover, the addition of fly ash has a positive influence on performance of the concrete regardless of the type of the exposure regime