On-Site Corrosion Characterization of 50-Year-Old PC Deck Beams

Many existing concrete structures, built around the middle of the last century, have now reached the end of service life and require maintenance interventions to repair degradation damage, especially due to corrosion of steel reinforcement. In order to correctly design the restoration interventions and fulfil safety, robustness and durability requirements through performance-based approaches, it is necessary to perform wide inspection and monitoring campaigns and evaluate the state of degradation of structures and infrastructural facilities, particularly bridges and viaducts. In the framework of the BRIDGE|50 research project (Residual Structural Performance of a 50-Year-Old Bridge) a study is ongoing on a group of PC deck beams obtained from a viaduct demolished in Turin after a 50-year service life. This paper discusses the preliminary results of the inspection activities carried out on these structural members, currently stored in a dedicated testing area for defining the criteria, methods and procedures for the characterization of the state of materials degradation, the condition structural assessment and the maintenance of concrete bridges and viaducts. In particular, both visual observations and non-destructive testing (NDT) have been carried out on deck beams to evaluate their corrosion state. This paper is focusing on electrochemical methods such as half-cell potential mapping and resistivity measurements. The properties of concrete of these reinforced elements will be also investigated by performing some analysis on samples collected during the inspection activities.