Galvanic corrosion in steel and aluminum bridges: standards research
Notice bibliographique
Résumé
Galvanic corrosion is one of the most prevalent corrosion problems of modern times, where dissimilar metals and alloys are routinely used in industrial applications. This report focuses on galvanic corrosion in bridge applications through a literature review, a comprehensive experimental study, advanced analysis, and the development of an evaluation tool, a guiding procedure, and a set of galvanic corrosion criteria. It aims to provide information and resources to bridge engineers to conduct a better assessment on galvanic corrosion in bridge design and management. A galvanic series was developed that provides a systematic collection and comparison of the corrosion tendencies of bridge alloys. It has demonstrated that a significant galvanic corrosion tendency warrants attention, but also revealed that a seemly low tendency could lead to substantial galvanic corrosion between two actively corroding metals. These findings support the need of a method for further evaluation: a measurement of galvanic corrosion rate that assesses how fast the anodic alloy loses its mass. A set of criteria to interpret the magnitude of galvanic corrosion risk was established by considering both galvanic corrosion rate, and a new concept of a ratio that takes account of the galvanic corrosion rate in the context of a general corrosion rate (Gal/Corr), providing a consistent assessment for the alloys studied in this project. These advancements subsequently enabled the development of a three-step guiding procedure for assessing galvanic corrosion. The experimental design and results provided the foundation on which 11 bridge alloys were studied by using quantitative electrochemical techniques, microstructural analysis, and visual inspection of samples tested in a salt-spray chamber. The results also support corrosion-mechanism-based mitigation strategies by countering the necessary conditions for galvanic corrosion to occur and considering the key factors that influence its magnitude; that is, how the assembly and configuration affect the cathode/anode surface area ratio and how an environment affects corrosivity. Another important finding was that the galvanic corrosion rate is not only governed by the driving force (potential difference) but also by individual corrosion behaviours of metals. Two actively corroding metals (e.g., weathering steel and a carbon steel bolt in a chloride-laden environment), despite having similar corrosion potentials, were found to produce a galvanic corrosion rate much higher than two less active metals having very different corrosion potentials (e.g., aluminum and stainless steel bolt). While effectively comparing the galvanic corrosion resistance of paired bridge alloys, galvanic corrosion is clearly shown to be materials-environment-configuration specific. For example, the galvanic corrosion rate of A325 Type I carbon steel bolt coupled with weathering steel was found to be high in chloride-laden environments; however, it would be expected to be low in a chloride-free environment. In the future, developing a better understanding of the corrosion performance of bridge metals and alloys, and systematically examining them in a manner similar to their mechanical properties is recommended. This applies particularly to aluminum bridges. Although aluminum’s corrosion potential indicates a high corrosion tendency, its actual corrosion rate can be low due to the protection from the corrosion products of aluminum oxides. It would be also beneficial to establish information about the individual corrosion properties of bridge alloys as a part of the alloys’ complete characterization, including their interactions with exposure conditions, concerning especially weathering steel since its corrosion behaviour in chloride-laden environments is not fully understood. There is also a need to further develop risk assessment criteria to interpret galvanic corrosion. This study represents an initial effort based on existing data, an experimental study, and a newly developed concept of the Gal/Corr ratio that has put the evaluation of galvanic corrosion in a new perspective and will hopefully spur interest and promote further discussion and research.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,015 | 0,015 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,001 |
| Méta-épidémiologie (sens large) | 0,001 | 0,001 |
| Bibliométrie | 0,010 | 0,008 |
| Études des sciences et des technologies | 0,001 | 0,002 |
| Communication savante | 0,004 | 0,004 |
| Science ouverte | 0,003 | 0,002 |
| Intégrité de la recherche | 0,002 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».