Effects of Deicers on Concrete Deterioration

Concrete specimens were exposed to weekly cycles of wetting and drying in distilled water and in solutions of sodium chloride, calcium chloride, magnesium chloride, and calcium magnesium acetate with either a 6.04 molal ion concentration, equivalent in ion concentration to a 15% solution of NaCl, or a 1.06 molal ion concentration, equivalent in ion concentration to a 3% solution of NaCl, for periods of up to 95 weeks. Specimens were also exposed to air only. The effects of exposure were evaluated based on changes in the dynamic modulus of elasticity and the physical appearance of the specimens at the conclusion of the tests. Concretes exposed to distilled water and air show, respectively, an increase and a decrease in dynamic modulus of elasticity, due principally to changes in moisture content; overall, no negative impact on the concrete properties of these specimens is observed. At lower concentrations, sodium chloride and calcium chloride have a relatively small negative impact on the properties of concrete. At high concentrations, sodium chloride has a greater but still relatively small negative effect. At low concentrations, magnesium chloride and calcium magnesium acetate can cause measurable damage to concrete. At high concentrations, calcium chloride, magnesium chloride, and calcium magnesium acetate cause significant changes in concrete that result in loss of material and a reduction in stiffness and strength.