Corrosion Protection Solutions for New and Deteriorating Structures
Zinc Layer Discrete Anode (ZLDA)
What is Zinc Layer Discrete Anode Used For?
Zinc Layer Discrete Anode is a self-contained, corrosion protection and durability enhancement system, designed to be incorporated within the concrete patch repair, using a suitable concrete repair material on atmospherically exposed reinforced concrete structures, to provide long-term protection from corrosion.
Zinc Layer Discrete Anode provides multi-staged corrosion protection, which effectively stops and prevents concrete deterioration resulting from reinforcement corrosion.
When connected to the embedded reinforcement and embedded within the concrete, the zinc anode corrodes and provides galvanic cathodic protection to the embedded reinforcement.
This product provides active corrosion control by cathodic protection, meeting the requirements of BS EN 1504 Part 9 Principle 10 (cathodic protection by applying an electrochemical potential) and provides benefits in line with Principal 7 (preserving or restoring passivity) of the embedded reinforcement.
Where installed with monitoring facilities, this product can be monitored and evaluated against the cathodic protection criteria listed within BS EN ISO 12696.
Zinc Layer Discrete Anode Product Description
Zinc Layer Discrete Anode utilizes Zinc Layer Anode technology and consists of a high purity zinc foil, complete with an ion-conductive, auto moistening, humectant/activator/adhesive layer.
The zinc foil/humectant/activator is wrapped around the centralized galvanized steel strip which is spot welded to the zinc foil, to form an elongated discrete anode, surrounded by a porous cotton membrane, which enables direct ionic contact between the anode and the surrounding reinforcement when embedded in concrete.
Two anode sizes are available, depending on exposure and life requirements:
ZLDA100 contains 180g of pure zinc.
ZLDA300 contains 540g of pure zinc.
Specific zinc weights and sizes can be fabricated to suit specific applications, design life, and performance requirements.
The anodes are installed directly onto exposed reinforcement using the galvanized perforated steel strip and mechanical connections and then embedded within a concrete repair using a suitable concrete repair material. Alternatively, the anodes can be connected to the reinforcement via a wired connection and monitoring facility for monitoring purposes.
Where Can Zinc Layer Discrete Anode Be Used?
Zinc Layer Discrete Anode is designed for protecting atmospherically exposed reinforced concrete structures, suffering from chloride or carbonation-induced reinforcement corrosion and resulting concrete deterioration.
Capable of stopping and preventing concentration cell corrosion (incipient anodes), Zinc Layer Discrete Anode, can limit or prevent the need for removal and replacement of sound undamaged chloride contaminated or carbonated concrete.
Suitable for use locally, to provide patch repair enhancement and prevent incipient anode formation, for concrete patch repairs in chloride contaminated concrete, or when incorporating old chloride contaminated structures into a new build.
For severely deteriorated structures requiring extensive concrete repairs, they can be used globally across the structure to provide corrosion protection, durability enhancement, and deterioration prevention in repaired and unrepaired, sound-contaminated concrete areas.
On new structures, they can be used to provide durability enhancement or deterioration prevention, when installed in the early life of a structure, to prevent the onset of corrosion-related deterioration, at high-risk areas, like construction joints, construction defect areas, or areas of low cover.
Zinc Layer Discrete Anodes can be used in conjunction with the surface applied Zinc Layer Anode, to provide enhanced protection in restricted access areas, such as bearing shelves, joints, or other difficult to reach areas requiring protection.
Suitable for use on high-risk elements like pre-stressed and post-tensioned structures, as it will not exceed the potential limits for susceptible high strength steel listed within BS EN ISO 12696, and requires no further potential limitation or control during operation.
Depending on the anode quantity, size, spacing, and prevailing exposure conditions, Zinc Layer Discrete Anode can:
Prevent early patch repair failure of chloride contaminated concrete for periods greater than 10 years.
Enhance the natural protection of cover concrete and prevent the onset of reinforcement corrosion of new structures, for periods of up to 20 years, compared with unprotected exposure conditions.
Technical Benefits of Zinc Layer Discrete Anode
Zinc Layer Discrete Anode can be installed as a stand-alone system, connected directly to the reinforcement, or provided with embedded monitoring facilities to meet the monitoring requirements listed within BS EN ISO 12696 - Cathodic Protection of Steel in Concrete.
The large surface area of the anode provides a low anode to cathode circuit resistance, ensuring the highest cathodic protection current flow under the natural zinc to steel, driving voltage.
The humectant/activator layer enables high dissolution and mobility of the zinc corrosion product, preventing loss of performance, typically found with embedded galvanic anode systems.
Once installed, Zinc Layer Discrete Anode provides multi-staged protection, which effectively stops and prevents concrete deterioration, resulting from reinforcement corrosion.
The protection afforded by Zinc Layer Discrete Anodes includes:
Stopping corrosion of the reinforcement by delivering cathodic protection.
Promotes passive film healing at corrosion sites on the embedded reinforcement by producing hydroxide.
Heals and maintains passive film stability on the reinforcement.
Consumes water and oxygen within the concrete through electrochemical reactions.
The system is easy to install, requires no additional AC or DC power for operation, and is relatively maintenance-free.
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