How is the MMO Anode Installed in Cathodic Protection?

Aug 24, 2022

How is the MMO Anode Installed in Cathodic Protection?

Before anode installation, the surface should be well prepared. The concrete surfaces intended to receive installation of anode material, e.g. conductive coatings or activated titanium mesh within a cementitious overlay, shall be prepared so as to present, as a minimum, a clean, non‑friable surface and in order that the substrate to overlay adhesion.

Cathodic protection conductive coatings generally require a minimum of preparation to leave a maximum of cement paste and minimal exposure of aggregate and should be as specified in the coating product specification and the cathodic protection system specification.

Anodes installed for the protection of steel in buried or immersed concrete may themselves be buried or immersed and may be quite remote from the structure. In these applications, the concrete surface needs no surface preparation. However, the surface may require excavation for visual inspection and confirmation that there are no coatings or water-proofing membranes applied to the concrete surface which would prevent the passage of cathodic protection current to the steel in the concrete.

MMO Anode Installation in Cathodic Protection Process
The anode system shall be installed by methods and under controlled environmental conditions which can be demonstrated by trials or past projects to enable the requisite anode performance to be achieved. The anode system shall be installed in accordance with the design method statements or specification for installation.Particular attention shall be given to the avoidance of short-circuits between the anode system and any reinforcement steel, ancillary metallic components or reinforcement of tie wire or debris steel in the concrete for impressed current systems.

After conductive coating or cementitious overlay or embedded anode applications, the atmospheric conditions and concrete surfaces shall be maintained at temperatures and humidity or moisture levels necessary to ensure proper curing/solvent loss/water evaporation of the anode and/or overlay.

Prior to application of any overlay, surface sealant or decorative coating over the anode systems, the anode/cathode resistance and potential difference shall be measured in order to determine whether short-circuits have been established and, if so, they shall be detected and corrected before further work for impressed current systems or galvanic systems or anode zones that require isolation for monitoring purposes.

Connections to the Anode System
Each zone of the impressed current cathodic protection system shall be provided with multiple positive cable/anode connections such that the failure of any one anode/cable connection shall not significantly impair the performance of the cathodic protection system in that zone.

The failure of any one anode/cable connection in a zone should not reduce the local zone anode current density by more than 10 % of the nominal anode current density at any location within the zone; anode/cable connections should be designed and located and also cable and anode volt drops should be designed to ensure such uniformity.

The anode/cable (or anode to reinforcement in galvanic anode applications) connection system shall be of a type and installed to such standards, as can be demonstrated by trials or past projects to enable the requisite anode and anode/cable connection performance to be achieved.

In each individual zone, the electrical resistance of all anode/cable connections shall be tested and compared with calculated values for the particular anode type and distribution. Data shall be assessed to determine whether additional testing or additional anode/cable connections are required.A 100 % visual inspection shall be undertaken of the anode system, including all related cables and cable connections, prior to application of any coating or overlay.