Cathodic protection of bridges in West Flanders with sacrifical anodes
The Sas Slijkensbrug which connects Bredene with Ostend is being completely renovated. The works are carried out by Renotec on behalf of the Road and Traffic Agency of the Flemish Government.
The works include performing concrete repairs in the bridge structure and modernizing the railings. The bridge deck gets a new waterproof membrane while the road and footpaths are renewed. Finally, the bottom of the bridge is painted again.
During the repair of the underside, pit corrosion of the reinforcement was diagnosed.
Deteriorating waterproofing and the use of deicing salts make that reinforcement in the bridge deck, joints and land heads corrode. As a result, the concrete is damaged.
This concrete damage is progressive and the damage image consists of either cracking of concrete or rust spots. In case of attack with chloride, the reinforcement show pitcorrosion. Such attack is not unusual in bridges and can affect the stability of the bridges.
During the repair of the bridges, further corrosion of the reinforcement can be stopped by the installation of the Galvashield sacrificial anodes of Fortius, Diest. www.fortius.be
For this, the Cl content (> 0.40% on cement content) and the amount of internal steel are determined. This data allows to determine the required amount of sacrificial anodes.
This system provides a durable solution and prevents recurring damage. It thus provides additional protection of the reinforcement steel and extends the service life of the repair and the bridge.