Galvashield N embedded galvanic anode units are used in new concrete construction to provide corrosion prevention to reinforcing steel. Galvashield N contains an innovative zinc anode core design surrounded by an enhanced formulated cement-based mortar. The anode unit is alkali-activated (Type A) with an internal pH of 14 or greater to keep the zinc active over the life of the anode while being non-corrosive to reinforcing steel. Galvashield N utilize 2G Technology™ to provide higher current output.
- Newly constructed reinforced concrete
- Long service life structures
- Extreme exposure conditions
- Global protection of large areas or specific structural elements
- Targeted protection around critical areas where future corrosion is likely such as around construction and expansion joints
Features and Benefits
- Proven technology – Galvashield anodes have an extensive 10+ year track record in the field and have received British Board of Agrément (BBA) approval.
- Type A anode – alkali-activated to maintain activity of zinc while being non-corrosive to reinforcing steel.
- 2G Technology™ – provides enhanced current output and protection.
- Cast zinc core – provides high anode utilization in addition to secure long-term connection between the zinc and the lead wires.
- Integral steel lead wires – allows for quick and convenient anode installation. Provides dependable steel-to-steel contact with no intermediate materials such as galvanizing that may compromise the long-term electrical connection. Extra long lead wires allow the anode to be tied in the center of the reinforcing grid to provide more even current distribution.
- Versatile – can be used for both conventionally reinforced and prestressed or post-tensioned concrete.
- Low maintenance – requires no external power source or system monitoring.
- Long lasting – direct protection provided during the 10 to 20 years* anode life. Extended corrosion mitigation is provided after anode consumption due to positive electrochemical benefits.
*As with all galvanic protection systems, service life is dependent upon a number of factors including reinforcing steel density, concrete conductivity, chloride concentration, humidity and anode spacing.
How It Works
When two dissimilar metals are coupled together in an electrolyte (in this case concrete), the metal with the higher potential for corrosion (zinc) will corrode in preference to the more noble metal (reinforcing steel). While the anode unit is active, a small direct current provides steel polarization sufficient to mitigate the initiation of corrosion for a given amount of chloride as well as serving to repel the movement of chloride ions away from the reinforcing steel. During this time, beneficial hydroxyl ions are generated and other cations such as calcium are attracted to the steel. This electrochemical reaction provides a residual benefit to the structure as the additional hydroxyl ions assist in maintaining the steel’s protective passive oxide film and creates a buffer against future chloride exposure after the anode is consumed.