| Abstract: | Corrosion behaviour of stressed and prestressed reinforcement in concrete structural elements In steel reinforced or prestressed concrete structures corrosion protection of the reinforcement is resulting from the high alkalinity of the concrete environment which guarantees passivity of the steel surface. The long time efficiency of the corrosion protection is a function of the design of the structure and influence from the properties of the used concrete materials as well as the environmental conditions of the structure. Essential factors preventing corrosion are given by a good quality and thickness of the concrete covering, a proper curing of the concrete and position of the reinforcement which avoids cracks and defects in the concrete covering. Passivity of the reinforcement can be destroyed by carbonisation of the concrete or a sufficiently high amount of chlorides in the concrete. Under such conditions in prestressing steels hydrogen induced stress corrosion occurs while in normal steel reinforcement the corrosion products due to their increasing volume lead to cracking and spalling of the concrete and a decreasing cross section of the reinforcement. In this report typical failures are demonstrated and discussed. |
