TY - CONF A1 - Beck, Matthias A1 - Goebbels, Jürgen A1 - Isecke, Bernd A1 - Burkert, Andreas A1 - Mietz, Jürgen T1 - Investigations of corrosion on small cathodes in reinforced concrete - observations and suggestions N2 - Corrosion of steel reinforcement in concrete exposed to chloride containing environments is a serious problem in civil engineering practice. The standards and guidelines contain only minimum requirements regarding concrete quality and concrete cover. In very critical cases, for example the ingress of chlorides, the application of different coatings is currently the only possibility to protect the reinforced concrete structures. In this case the modelling of reinforcement corrosion would be more practical. One sub-project of a DFG-research project (FOR 537) is currently performed at the Federal Institute for Materials Research and Testing (BAM). Aim of the sub-project is the description of corrosion propagation and the characterization of the corrosion on specimens with small cathodes by electrochemical parameters. The electrochemical parameters are determined by suitable electrochemical measurements, considering concrete parameters as well as different environmental conditions. T2 - EUROCORR 2009 CY - Nice, France DA - 2009-09-06 KW - Self-corrosion KW - Steel reinforcement KW - Concrete parameters KW - X-ray tomography PY - 2009 IS - Paper 7976 SP - 1 EP - 13 AN - OPUS4-20063 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mietz, Jürgen A1 - Raupach, M. A1 - Goltermann, P. T1 - Integrated Monitoring System for Reinforced Concrete Structures T2 - 1st FIB congress CY - Osaka, Japan DA - 2002-10-13 KW - Reinforcement corrosion KW - Sensors KW - Inspection KW - Maintenance KW - Bridge management PY - 2002 IS - 15 SP - 29 EP - 38 CY - Osaka AN - OPUS4-1727 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mietz, Jürgen A1 - Isecke, Bernd A1 - Fischer, Joachim T1 - Long-term experiences with cathodic corrosion protection of steel reinforced concrete structures T2 - 15th International Corrosion Congress CY - Granada, Spain DA - 2002-09-22 PY - 2002 PB - CSIC, Spanish Council for Scientific Research CY - Madrid AN - OPUS4-1728 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Isecke, Bernd A1 - Mietz, Jürgen T1 - Einsatz nichtrostender Stähle in Schwimmbädern T2 - Fachtagung des Nederlands Corrosie Centrum CY - Breda, Niederlande DA - 2002-11-14 PY - 2002 AN - OPUS4-1845 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mietz, Jürgen T1 - Aktuelle Probleme bei bestimmten vergüteten Spannstählen T2 - Fachtagung "Sonderkapitel aus dem Brücken- und Ingenieurbau" CY - Berlin, Deutschland DA - 2000-11-13 PY - 2000 SP - 87 EP - 99 PB - BAM CY - Berlin AN - OPUS4-981 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ebell, Gino A1 - Poltavtseva, Marina A1 - Mietz, Jürgen T1 - Electrochemical investigation of carbon-based conductive coatings for application as anodes in ICCP system of reinforced concrete structures N2 - Carbon‐based conductive coatings are complex composites, consisting of an organic or inorganic binder and conductive carbon components, for application as anodes in impressed current cathodic protection systems of reinforced concrete structures. The electrochemical properties of three coatings at different humidity and in saturated calcium hydroxide solution were studied by electrochemical methods, such as electrochemical impedance measurement, measuring of open circuit potential over time and galvanostatic polarization. The dissolved organic and inorganic carbons in electrolyte solution were quantified by using a photometric method. The structures of the coatings were investigated before and after the electrochemical tests by microscopy and scanning electron microscope/EDX analysis. The results of the electrochemical impedance measurements show that the tested coatings all have a relatively low resistance, which is between 100 and 200V. The binder and the surface porosity influence the degradation behavior of those coatings. Especially the organic binder reacts with the strong alkaline medium under dissolving of organic carbon. T2 - EUROCORR 2014 - European corrosion congress CY - Pisa, Italy DA - 08.09.2014 KW - Cathodic protection KW - Concrete KW - ICCP PY - 2014 SN - 978-3-89746-159-8 SP - O-7489, 481 EP - O-7489, 481 AN - OPUS4-31430 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ebell, Gino A1 - Mietz, Jürgen A1 - Burkert, Andreas T1 - Investigation of chloride-induced pitting corrosion of steel in concrete by a combination of electrochemical methods with X-ray tomography N2 - Steel in concrete is protected by the alkaline pore water environment and the resulting formation of a protective passive layer against corrosion. Adverse environmental conditions due to carbonation or chloride ingress can destroy the passive layer on the steel surface. Corrosion processes starting in those areas lead to uniform corrosion or local corrosion like pitting corrosion. In comparison to uniform corrosion pitting corrosion is a form of increased local corrosion and thus leads to a progressive reduction in cross-section of the reinforcing steel. The corrosion products are first absorbed by the pores of the concrete matrix, without causing visible external changes at the concrete surface. T2 - EUROCORR 2014 - European corrosion congress CY - Pisa, Italy DA - 08.09.2014 KW - Corrosion KW - Rebar KW - Chloride KW - Pitting corrosion PY - 2014 SN - 978-3-89746-159-8 SP - O-7207, 274-275 AN - OPUS4-31431 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Poltavtseva, Marina A1 - Ebell, Gino A1 - Mietz, Jürgen T1 - Entwicklung und Erprobung einer neuen Prüfmesszelle für elektrochemische Untersuchungen leitfähiger Beschichtungen auf Karbonbasis in Elektrolytlösungen N2 - Leitfähige Beschichtungen auf Karbonbasis können als sogenannte Anstrichanode (Sekundäranode) für den Kathodischen Korrosionsschutz (KKS) von Stahlbetonbauteilen zum Einsatz kommen. Die Beschichtungen sind komplexe Verbundwerkstoffe, die aus einem Bindemittel, leitfähigen Füllstoffen, einem Lösemittel und Additiven bestehen. Als Bindemittel bzw. Matrix werden anorganisch-mineralische und organische Materialien verwendet, diese werden üblicher Weise für Fassadenfarben, Putze, Estriche und Mörtel in der Bauindustrie genutzt. Als leitfähige Pigmente für die Beschichtungen werden häufig feines Graphitpulver, Industrieruß und Kohlefaser verwendet. Die Mischung wird als Paste oder wässrige Dispersion auf die entsprechend vorbereitete Betonoberfläche aufgetragen und kann dadurch eine gleichmäßige Verteilung des Schutzstromes auf einer großen Oberfläche gewährleisten. Für die Stromzuführung vom Gleichrichter in die Beschichtungen werden in definiertem Abstand Drähte (sog. Primäranode) aus z.B. platiniertem Titan, Kupfer oder mischoxidbeschichtetem Titan eingebaut. Der Minuspol des Gleichrichters wird an der Bewehrung und der Pluspol an der Primäranode angeschlossen. Beim Anlegen eines Schutzstromes, der zwischen der Anode und der Kathode fließt, wird das Potential des Bewehrungsstahls unterhalb -720 mV (gegen Ag/AgCl/0,5 M KCl) in einer inaktiven Potentialbereich abgesenkt und der Korrosionsvorgang unterdrückt. Der Stromfluss wird durch die elektrolytische Leitfähigkeit des Betons bzw. Betonporenwassers und durch elektrochemische Reaktionen an der Anodenoberfläche und der Kathodenoberfläche ermöglicht. Dabei werden an der Oberfläche des Bewehrungsstahls, durch die elektrochemische Reduktion von Sauerstoff, alkalisch wirkende Hydroxylionen (OH’) gebildet und an der inerten Anodenoberfläche wird Wasser (bzw. Hydroxylionen) zu Sauerstoff oxidiert. T2 - 15. Sommerkurs Werkstoffe und Fügen am Institut für Werkstoff- und Fügetechnik CY - Magdeburg, Germany DA - 12.09.2014 PY - 2014 SN - 978-3-940961-85-3 SP - 207 EP - 214 AN - OPUS4-31474 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ebell, Gino A1 - Poltavtseva, M. A1 - Mietz, Jürgen ED - Ottosen, L. T1 - Electrochemical investigation of carbon-based conductive coatings for application as anodes in ICCP system of reinforced concrete structures N2 - Carbon-based conductive coatings are complex composites, consisting of an organic or inorganic binder and conductive carbon components, for application as anodes in impressed current cathodic protection systems of reinforced concrete structures. The electrochemical properties of three coatings at different humidity and in saturated calcium hydroxide solution were studied by electrochemical methods, such as electrochemical impedance measurement, measuring of open circuit potential over time and galvanostatic polarization. T2 - International RILEM Conference on Materials, Systems and Structures in Civil Engineering 2016 CY - Lyngby, Denmark DA - 21.08.2016 KW - ICCP KW - Coating KW - Cunductive KW - Corrosion KW - reinforcement KW - Concrete KW - Cathodic protection PY - 2016 SN - 978-2-35158-176-6 SN - 978-2-35158-177-3 VL - Proceedings PRO 111 SP - 43 EP - 46 PB - RILEM Publications S.A.R.L. CY - Paris, France AN - OPUS4-37216 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ebell, Gino A1 - Burkert, Andreas A1 - Mietz, Jürgen T1 - Hydrogen evolution on galvanized rebar in fresh concrete with different chromate-reduced cements N2 - The reduction of the chromate contents in cements affects the electrochemical reactions of galvanized reinforcing steels in fresh concrete. It is important to investigate the critical conditions in the first hours following the pouring of the concrete. T2 - EUROCORR 2015 - European corrosion congress CY - Graz, Austria DA - 06.09.2015 KW - Hydrogen evolution KW - Concrete KW - Galvanized rebar KW - Reinforcement KW - Chromate PY - 2015 SP - paper 9_703 AN - OPUS4-34619 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -