INVESTIGATIONS OF REINFORCEMENT CORROSION .2. ELECTROCHEMICAL MONITORING OF STEEL IN CHLORIDE-CONTAMINATED CONCRETE

Corrosion rates of steel rods embedded in concrete specimens similar to those of Part 1 have been determined by linear polarization. For specimens exposed to external sources of chloride the probability of depassivation increased with the chloride:hydroxyl concentration in the pore solution, beyond a threshold ratio of approximately 3. Thereafter corrosion was subject to anodic control. Chlorides introduced as admixtures tended to promote corrosion at somewhat lower chloride:hydroxyl ratios. Rankings of the materials and exposure regimes studied in terms of their corrosion severity have been established, and problems in relating the behaviour of laboratory specimens to that of reinforced concrete structures are considered.