Filtern
Dokumenttyp
Sprache
- Englisch (2)
Referierte Publikation
- ja (2) (entfernen)
Schlagworte
- Cathodic protection (2) (entfernen)
Chloride-induced damage of reinforcing steel is especially for parking garages and bridges often very severe as large amounts of chlorides act on horizontal surfaces which could lead to fast ingress of these detrimental ions up to the level of the reinforcement and subsequently to high rates of corrosion.
In order to avoid the disadvantages of conventional rehabilitation (unreliable prognosis with patch repair or high costs and regular maintenance with cathodic protection using impressed current) a new combined protection system was developed where the principle of drying out the concrete (by means of a surface protection system) is combined with a temporary cathodic protection (by means of a sprayed zinc layer) during the transitional period of the drying out process.
This new system was tested both in the laboratory and on-site at a pilot application. Based on the results obtained the possibilities and limitations of the new system are discussed in this paper.
Cathodic protection (CP) is a common method for rehabilitation of reinforced concrete structures suffering from Chloride induced corrosion. A sufficient protection of the corroding rebar can be ensured by use of several protection criteria. The use of these assessment criteria, in particular the so called 100 mV-criterion, can lead to erroneous resuits for certain unconventional arrangements of rebar and cp anode.
Therefore a joint research project of the Institute for Building Materials Research, RWTH-Aachen University, Germany, (ibac) and the Federal Institute for Materials Research and Testing, Berlin, Germany, (BAM) has been set up to determine the applicability of CP under arbitrary geometrical conditions. A special focus was set on the applicability of surface applied anode Systems for protection of the reinforcement of structures opposite to the accessible side (e.g. outer side of tunnel Shell, Bridge deck protected from inside a box girder) In this paper, the impact of the time dependent changes of the Polarisation behaviour of the rebar on the current and potential distribution is shown by means of parametric studies using the FEM method.