A study of the effect of chloride binding on service life predictions

One of the major causes of deterioration of reinforced concrete structures is chloride-induced corrosion of the reinforcing steel. The magnitude of the damage is especially large in structures exposed to marine environments and de-icing salts. The capacity of the concrete cementitious system to bind chloride ions has an important effect on the rate of chloride ionic transport in concrete and on the corrosion initiation of the steel reinforcement. This paper reviews mathematical models used in the literature to describe chloride binding in concrete. The impact of the different binding relations on the time - dependent chloride penetration profiles is investigated by solving the chloride mass conservation statement with a finite-difference approach. Results are presented for a concrete structure subjected to two different exposure conditions: submerged in seawater and exposed to de-icing salts. The implication of accounting for chloride binding in service life estimations is discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.