Galvanic corrosion of aluminium alloy members of bridge guiderails under severe atmospheric exposure conditions

ABSTRACT

Aluminium alloys are nowadays preferred as materials for bridge guiderails especially for bridges connecting oceanic islands or spanning inlets due to their inherent corrosion resistance. But because of the limited mechanical strength of aluminium alloy, fasteners of guiderail members are made from steel materials. It has been found that contact between bare steel fasteners and aluminium alloy members can cause galvanic corrosion in the aluminium alloy. Research was carried out to investigate the capability of different surface treatments on fasteners and aluminium alloy members to inhibit galvanic corrosion under atmospheric exposure for periods of one and three years. It was found, among other results, that stainless steel fasteners treated with zinc flake coating were the most effective inhibitors of galvanic corrosion on aluminium alloy members.

KEYWORDS:

• Galvanic corrosion
• aluminium alloy
• stainless steel bolt
• atmospheric exposure test
• surface treatment

Acknowledgement

This study was carried out with the support of the Japan Aluminium Association. The authors would like to express their immense gratitude to Japan Aluminium Association for institutional support which made it possible for this research to be carried out more successfully. They also thank all members of the Association’s Research Committee for their advice and recommendations throughout the study period.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors would like to express their immense gratitude to the Japan Aluminium Association for institutional support.