Rapid Evaluation of Corrosion-Resistant Concrete Reinforcing Steel in the Presence of Deicers

Research to evaluate the properties of a corrosion resistant concrete reinforcing steel is reported. The steel is microalloyed (using copper, chromium, and phosphorous), and subjected to a special heat treatment, to provide corrosion resistance superior to conventional reinforcing steel. Rapid tests, developed at the University of Kansas, are modified and used to evaluate the corrosion properties of four types of steel representing combinations of alloying elements and heat treatment. The steels include two conventional steels, one hot-rolled and one subjected to a quenching and tempering heat treatment, and two corrosion-resistant steels, one hot-rolled and one heat-treated. The steels are evaluated in the presence of three deicing chemicals: sodium chloride, calcium chloride, and calcium magnesium acetate. The results indicate that the corrosion resistant steels exhibit a corrosion rate equal to about one half that of the conventional steels. At low concentrations, calcium chloride and calcium magnesium acetate appear to have a corrosive effect similar to sodium chloride. Calcium magnesium acetate appears to be less corrosive than calcium chloride and sodium chloride at intermediate concentrations. High concentrations of CaCl, and CMA appear to cause instability in the macrocell test, causing alternating patterns of active corrosion and passivation of the anode specimens.