Corrosion monitoring and fracture detection in prestressed concrete structures - Possibilities and limits

Corrosive influences may affect the long-term functionality of prestressed elements of prestressed concrete constructions and may lead to catastrophic failure of the member Hence, the objective of the condition assessment of prestressed components has to be detecting existing defects and damages of the prestressed elements, e.g. grouting faults, corrosion and steel fractures in time. For an objectively early diagnosis of corrosion damages on prestressing elements, the Structural Health Monitoring (SHM) based on non-destructive testing and monitoring methods is predestined. In this contribution causes of tendon corrosion in prestressed concrete (PC) bridges will first be specified, furthermore advantages and the strategy of corrosion monitoring are presented. Afterwards the state of the research and art of non-destructive techniques and evaluation (NDT/NDE) of the corrosion state and of fracture detection of the prestressed elements in bridges with its possibilities and limits will be discussed. In this context also innovative sensors and measuring methods developed by the authors at the iBMB within the collaborative research center (CRC) 477 "Structural Health Monitoring" will be introduced.