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- Self-corrosion (4)
- X-ray tomography (4)
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- Electrochemical measurements (2)
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- Potentialverlauf (2)
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Eingeladener Vortrag
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Modellierung von Bewehrungskorrosion - Betontechnologische Einflüsse auf elektrochemische Parameter
(2006)
Modelling of reinforcement corrosion - Influence of concrete technology on corrosion development
(2006)
Reinforcement corrosion is influenced by different parameters like resistivity of concrete, setting conditions and also by concrete technology. Moreover the presence of cathodic areas and the possibility of unhampered cathodic reaction influences the reinforcement corrosion. In this paper the development of corrosion without large cathodic areas, called self-corrosion, considering different concrete parameters, is studied.
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 and large cathodes, by electrochemical parameters. The electrochemical parameters are determined by suitable electrochemical measurements, considering concrete parameters as well as different environmental conditions.
Corrosion of steel reinforcement in concrete exposed to chloride containing
environments is a serious problem in civil engineering practice. Electrochemical
methods, e.g. potential mapping, provide information whether the steel reinforcement
is still passive or depassivation has been initiated. By applying such techniques no
information on the type of corrosion, its extent and distribution of corrosion products
is available. Particular the corrosion progress is a significant problem. Especially in
the case of element corrosion in reinforced concrete structures, the development at
the anode can not be separated into corrosion damage causing by element corrosion
or self-corrosion. Until now also in laboratory tests it is impossible to collect such
information without destroying specimens after electrochemical testing was
performed place. To overcome this problem it was tried to study the steel surface
within the mortar specimens by X-ray tomography (CT). Within the scope of these
investigations it could be shown, that X-ray tomography is suitable to make corrosion
pits visible which are embedded in a mortar with a cover thickness of about 35 mm.
In this publication the corrosion damage of reinforced steel is documented timedependent
by X-ray tomography.
Corrosion of steel reinforcement in concrete exposed to chloride containing environments is a serious problem in civil engineering practice. Electrochemical methods, e.g., potential mapping, provide information whether the steel reinforcement is still passive or depassivation has been initiated. By applying such techniques no information on the type of corrosion, its extent and distribution of corrosion products is available. Particular the corrosion progress is a significant problem. Especially in the case of macrocell corrosion in reinforced concrete structures, the development at the anode cannot be separated into corrosion damage resulting from macrocell corrosion or self-corrosion. Until now also in laboratory tests it is impossible to collect such information without destroying specimens after electrochemical testing was performed. To overcome this problem it was tried to study the steel surface within the mortar specimens by X-ray tomography (CT). Within the scope of these investigations it could be shown, that X-ray tomography is suitable to make corrosion pits and their development visible which are embedded in a mortar with a cover thickness of about 35 mm. In this publication the time-dependent corrosion damage of reinforced steel is documented by X-ray tomography.