Sustainable retrofits on reinforced concrete infrastructures

The infrastructure sector is paying increasing attention to sustainability. In particular, certain events have proven how preventive local interventions can save both user lives and the same infrastructures, thus highlighting the importance of maintenance. The ineffectiveness of concrete repairs is one of the main issues in civil engineering. Merely 50% of restoration operations on concrete buildings is considered to be effective in Europe, although rehabilitation costs cover nearly half of the annual construction investments. This study investigates a potential strategy to improve the sustainability of infrastructure restoration solutions. A simplified examination of CO2 emissions, intervention costs, social factors, structural performances, and other factors considered relevant for this research, is followed by a comparison and ranking of the potential rehabilitation solutions. Four approaches have been selected to design retrofit interventions on a real column of the Sardinian Brabau bridge in Italy: i) complete column replacement; ii) substitution of the damaged longitudinal rebars with machined bars and the casting of a new concrete cover in ultra-high performance fibre-reinforced concrete; iii) longitudinal and transverse fibrereinforced polymer wrapping; iv) concrete jacketing at the base. Through the application of selected criteria, a methodological and procedural approach is developed. It provides a tool for assessing the sustainability of infrastructure maintenance works throughout the entire life cycle in the subsequent phases of this research.