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This research program examines the performance of different patch repair strategies for repairing concrete bridge deck slabs, damaged due to premature corrosion of embedded reinforcing steel bars (rebars). The electrochemical compatibility between the repaired patch concrete and the existing old concrete in fifteen (1000 mm × 1000 mm × 200 mm) specimens was examined using half-cell potential, chloride content, rebar mass loss and corrosion penetration rate tests. The experimental results showed that the potential difference between the repaired patch concrete and the existing old concrete local corrosion increased significantly at the periphery of the patch, and gradually progressed into the repaired zone. This effect varied from one repair technique to another. Different measures to increase the service life of the repair system are also proposed, such as incorporating a sacrificial embedded anode, an impressed current cathodic protection system, along with the use of surface coating or membrane as an additional line of defence. [ABSTRACT FROM AUTHOR]

This paper presents a practice-oriented method for design of flexural concrete members for a given service life in an aggressive environment. A time-dependent correlation between rebar corrosion level in terms of mass loss and its bond strength degradation at the steel–concrete interface, and the ultimate flexural and shear resistances of the reinforced concrete elements is evaluated using basic electrochemistry and empirical relationships. The design development length is determined based on the mass loss prediction and the equation depicting loss of bond strength with mass loss due to corrosion. The results show that the mass loss of rebars depends on several factors, such as the surface chloride concentration, cover thickness to rebar and concrete permeability, rebar size and ratio of the concrete cover thickness to the rebar diameter ( c/d b ratio). The model results predict the required development length at the end of the service life of 70 years to be more than twice that obtained from conventional reinforced concrete design. The proposed durability design procedure is illustrated with the help of a detailed design example. Analysis results show that because of corrosion the flexural and shear strengths decrease by about 80% and 52%, respectively, after the service life of 70 years. [ABSTRACT FROM AUTHOR]