CONCRETE CORROSION TAMED FOR UP TO 50 YEARS

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Sika's Ferrogard Duo hybrid anode system was recently installed on the bridge and causeway over the Whau River and Estuary on Auckland's State Highway 16.

Sika’s Ferrogard Duo hybrid anode system was recently installed on the bridge and causeway over the Whau River and Estuary on Auckland’s State Highway 16.

For the owners of large, corrosion-prone concrete assets in aggressive coastal environments, Sika has two systems that can significantly reduce maintenance costs.

The Sika Ferrogard Patch system increases the durability of traditional concrete patch repairs by providing protection against incipient anode corrosion. Although using galvanic anodes in concrete patch repair is not new, Sika Ferrogard Patch anodes deliver improved performance and reliability over previous systems. By placing the anodes outside the repair, they are closer to the area where corrosion is most likely to occur and are therefore more effective at preventing corrosion initiation.

The improved reliability of the Sika Ferrogard Patch system is reinforced by it being active without the traditional requirement to pre-soak the anodes in water, therefore eliminating one critical installation step that is frequently overlooked. This also means the anodes are immediately active when installed, irrespective of whether the contractor has completed the patch repair.

The system provides up to 50 years of reinforcement corrosion protection without the need for regular monitoring and maintenance and it is fully compatible with pre-stressed concrete structures. This system greatly extends asset life and reduces ongoing maintenance costs to almost nothing. It is a hybrid system using discrete zinc anodes that are operated initially in a temporary impressed current corrosion protection phase before switching to the galvanic protection phase.

The impressed current phase, which typically uses a 12V power supply for just two weeks, halts reinforcement corrosion and ensures the steel reinforcement is fully passivated and in a non-corrosive environment. No further monitoring, maintenance or adjustment of the system is required for up to 50 years.

For more information, visit www.Sika.co.nz

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