Corrosion and moisture monitoring for condition monitoring of structures
For the condition monitoring of reinforced concrete structures, there are numerous investigation methods such as potential field mapping, concrete cover measurement, etc., which are capable of providing sufficiently accurate information on the condition of the structure for a large number of applications. However, these conventional methods repeatedly reach their limits - either because structural components are not accessible or because examinations are only possible after the removal of a coating. In these cases, corrosion monitoring is a valuable tool for reliably determining the condition of the structure even under difficult boundary conditions. But corrosion monitoring can do much more: possible damage mechanisms can be identified long before reinforcement corrosion occurs, and uncertainties, e.g. regarding the magnitude of the critical chloride content, can be eliminated. Since 2001, corrosion monitoring has been indispensable for repairs carried out in accordance with procedure 8.3 of TR-IH or W-Cl of the RL SIB, when the chloride-contaminated concrete is not removed.
Corrosion monitoring can be applied in every life cycle phase of structures. It starts directly after completion with moisture sensors, which can be used to monitor the effectiveness of coatings or hydrophobic treatments. Likewise, in new construction projects, corrosion sensor systems with depth staging can be used to monitor the time-dependent penetration of a carbonation or chloride front into the concrete, providing timely indications of any intervention measures that may be required. More demanding is the use in existing structures, where sensors have to be installed without influencing the system too much. For this purpose, either ready-made sensor systems can be installed or measurements can be carried out directly on the existing reinforcement using the approaches developed by our office.
Ingenieurbüro Schiessl has more than twenty years of experience in corrosion monitoring on bridges, tunnels, parking garages, bored pile and diaphragm wall structures or chemical plants. The sensor systems of our subsidiary Sensortec GmbH have been used worldwide for decades for corrosion monitoring on harbor structures, tunnels, high-rise foundations up to the Hong Kong-Zhuhai-Macao Bridge, the longest bridge in the world. Our expertise and experience have found their way into numerous technical publications, including Code of Practice B12 "Corrosion Monitoring" of the German Society for Non-destructive Testing, as well as into the draft of the Corrosion Monitoring Guideline of the German Committee for Reinforced Concrete. Particularly in the field of corrosion monitoring when applying method 8.3 according to TR-IH, we have been able to make a significant contribution to numerous economic and sustainable repairs through innovative measurement technology.
WunderleBeck, J.; Mayer, T. F.; Zausinger, C.; Gehlen, C. (2022):
Korrosionsmonitoring zum Wirksamkeitsnachweis des Instandsetzungsverfahrens 8.3 (W-Cl)
Beton und Stahlbetonbau, https://doi.org/10.1002/best.202200081
Mayer, T. F.; Gehlen, Ch.; Dauberschmidt, Ch.:
Corrosion Monitoring in Concrete
Yang, L.: Techniques for Corrosion Monitoring, 2nd edition. Woodhead Publishing, Duxford, 2021
Mayer, T. F.; Dauberschmidt, Ch.; Bruns, M.; Eichler, Th.; Wiens, U.; Mietz, G.; Gehlen, Ch.; Ebell, G.; Gerhardt, G.; Osterminski, K.:
Das Instandsetzungsprinzip W-Cl - Stand der Technik, baurechtliche Einordnung, aktuelle Forschungsarbeiten
Bautechnik 97 (2020), Heft 1
Mayer, T. F.; Harnisch, J.; Ebell, G.; Dauberschmidt, Ch.:
Korrosionsmonitoring von Stahlbeton-bauwerken – Das DGZfP-Merkblatt B12
Beton- und Stahlbetonbau 113 (2018), Heft 9
Hiemer, F.; Wich, F.; Gehlen, Ch.; Keßler, S.; Mayer, T. F.:
Monitoring von Bewehrungskorrosion in Rissbereichen von Stahlbetonbauwerken
Ernst & Sohn Special 2018 „Messtechnik im Bauwesen“, S. 35 - 43. Ernst & Sohn-Verlag, Berlin, 2018