Influence of the type of the de-icing salt on its diffusion properties in cementitious materials at different temperatures

Northern countries are submitted to extremely cold temperatures in winter. A huge amount of de-icing salt is used during that time to improve user safety on roadways. Consequently, most of de-icing salts, which are chloride based, lead to the degradation of the exposed structures through corrosion. In this paper, laboratory experiments and their duplicates by simulations determined the influence of calcium, magnesium, and sodium chloride in concrete specimens and the chloride aggression on concrete structures at different temperatures (21 °C, 5 °C and −1 °C). Immersion tests were carried out with two different concretes (CEM I/GU) with w/c ratios of 0.45 and 0.65. Modelling was performed using PhreeqC, a multi-species transport model that accounts for the cementitious material's chemical reactions. These tests highlighted the influence of the temperature and the chemical reaction with chloride ions depending on the co-ions associated (Na, K and Ca). The simulations also indicated that NaCl salts more react with the cement phases than MgCl2 and CaCl2, regardless of the temperature. Then, less chloride will be available sooner to corrode concrete reinforced structures in practice.