Galvanic Corrosion in Concrete Containing Calcium Chloride

The four experiments described show that galvanic corrosion of metals embedded in concrete is intensified by additions of calcium chloride to the concrete: 1. When aluminum and steel sheet, embedded in concrete and connected externally, were exposed up to one year in the atmosphere and also buried in soil, galvanic corrosion of aluminum was proportional to concentration of calcium chloride. 2. When steel-aluminum couples of various area ratios were exposed, galvanic corrosion was found to be proportional also to the steel-aluminum area ratio. 3. When aluminum conduit was embedded with steel reinforcing bars, in parallel rows, with the steel at increasing distances from the aluminum, galvanic corrosion suffered by the aluminum was inversely proportional to the distance separating the metals. 4. Where large slabs of reinforced concrete, similar to many structures, were cast with aluminum and steel embedded in them (some conduit specimens coated with bituminous paint), results showed that calcium chloride promotes galvanic corrosion when aluminum is coupled to steel or in contact with it; bituminous paint is beneficial in preventing attack.