| Abstract
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Durability of reinforced concrete infrastructure is severely affected by corrosion of reinforcing steel. Conventional patch repair techniques are unable to stop this corrosion due to electrochemical incompatibility between the "repaired" concrete and the original "chloride-infested" concrete. This research was undertaken to compare the performance of different patch repair strategies of corroded concrete bridge deck slabs, proposed by different industrial partners, with respect to the conventional patch repair. The results show that the potential difference between the "repaired-patch" concrete and the "existing" concrete accelerates local corrosion around the patch, and gradually progresses towards the repaired zone. Beneficial effect of sacrificial anodes and corrosion inhibitors in a KCl and a NaCl environment, are evaluated at the beginning of the repair, however, their effectiveness decreases with time. Corrosion penetration rate obtained from Tafel Test, overestimated the actual rebar mass loss, indicating the need for more research in this area. It is recommended that for new construction, concrete must have low diffusivity to avoid premature deterioration, and for repair, electrochemical protection systems such as cathodic protection, embedded sacrificial anode, corrosion inhibitor, and chloride extraction should be considered to increase the service life of the repaired system. Surface coatings such as zinc, epoxy, sealer or membrane can be used as additional line of defence. In addition, the existing cracks must be treated, and the bridge deck drainage system and expansion joints must be designed properly to avoid ingress of chloride-contaminated water into the concrete. (Abstract shortened by UMI.)
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