• Advice regarding the possible implementation of cathodic protection and the choice of a specific CP system. There are already dozens of commercial CP systems on the market worldwide. The choice of the most suitable system for every application is of great importance. It is not only about the choice between galvanic CP or ICCP, but within each system also the choice for a specific type of anode.
   
• Design of a CP system: when the choice has been made to opt for cathodic protection, a concrete design must be made. This includes the choice of the most suitable anode system, the number of anodes and their placement, the cabling, the measuring and power supplies, the measuring cells (RE's), the monitoring, the zoning, etc. The design is based on the most recent standards on cathodic protection of steel reinforcement in concrete structures (EN ISO 12696: 2016, CUR recommendation 45).
   
• Installation of test surfaces: in certain situations it may be interesting to test the operation of a CP system on a small scale before proceeding with its installation on the entire structure. SANACON offers the possibility to install a test surface and to monitor it for a certain time. Based on the results of the monitoring, it is checked if the criteria for the protection of the steel are achieved and a more accurate prediction can be made with regard to the lifetime of the CP system.
   
• Carrying out control measurements: after installation of a CP system, periodic control measurements must be performed (mandatory annually with a ICCP system and strongly recommended with a galvanic CP system). On the basis of these measurements, the operation of the system is evaluated and (in the case of a system with impressed current) adjustments can be made if necessary. SANACON is able to perform control measurements itself and critically analyze results from control measurements to make a decision about the efficiency of the system.

What?

Cathodic protection (CP) is a form of corrosion control in which steel is protected by joining it with another metal. The technique originated from the corrosion control of steel structures (e.g. steel pipelines), but its application expanded in the 1970s to steel reinforcement of concrete structures. Cathodic protection can be divided into two types of systems: galvanic or by impressed current.

With CP based on galvanic anodes (also called sacrificial anodes), the reinforcing steel is electrically connected to another metal that is less noble than steel, such as zinc, magnesium or aluminum. A galvanic cell is created by the connection of the two metals, whereby the less noble metal dissolves, i.e. corrodes. The less precious metal therefore sacrifices itself to protect the steel.

In the case of CP with impressed current (ICCP), an inert anode (e.g. carbon or titanium) is applied to or in the concrete. A voltage is applied between the anode and the steel by connecting it to an external power supply. By applying a voltage difference, an ion current flows through the concrete, which ensures that the reinforcing steel functions as a cathode, thereby stopping the corrosion process of steel.

Why?

Today, a large part of the construction budget is spent on the repair and maintenance of existing concrete structures. Corrosion of reinforcing steel (popularly called 'concrete rot') is responsible for 55% of all sustainability problems. If problems with reinforcement corrosion are not dealt with, this can lead to cracking in the concrete or the release of concrete debris. The problem of corrosion is nowadays often tackled by a traditional concrete repair. However, this is a process where a lot of concrete has to be removed and replaced, which makes the technology very labor-intensive. Moreover, in recent years many cases have emerged where a traditional concrete repair turned out to be unsustainable. Cathodic protection offers a less invasive alternative to traditional concrete repair, whereby the durability of the repair is also guaranteed for a longer timespan.