8 Pages

Corrosion initiation state of rebars in concrete subjected to chloride penetration

G.M. Sadiqul-Islam & T. Sugiyama

ABSTRACT: Corrosion of embedded steel reinforcement is one of the key factors which controls the durability and service life of concrete structures. In this research half-cell potential of rebars in concrete subjected to a sodium chloride solution of 10% in the concentration, has been monitored continuously using an embedded reference electrode in the concrete and computer operated automatic data logger system. A portable corrosion meter was also employed periodically for half-cell potential and AC impedance measurement to verify the initiation of corrosion estimated by the former system. Both systems allowed assessing the state of corrosion initiation. Chloride profiles for total chloride concentration were obtained using a conventional acid extraction method and an automatic titration device. Rebar corrosion areas were determined in connection with measured corrosion currents. Through the Thermo-Gravimetry/ Differential Thermal Analyzer (TG/DTA) the CH (portlandite) contents were estimated.