Corrosion of Steel Reinforcement in Concrete
(CTI Technical Note C1)
When steel reinforcement is encased in sound dense concrete, the entire surface of the steel is covered by a stable protective oxide film that forms in the alkaline environment created by the hydration of the cement in the concrete. Under these circumstances no corrosion of the reinforcement can occur. However, if the protective oxide film is locally destroyed, areas of different potential can be set up on the surface.
There are two ways that this protective oxide film might be destroyed. These are the reduction of the pH of the concrete by carbonation and the ingress of chloride ions.
This Technical Note provides an overview of these mechanisms of corrosion of steel reinforcement in concrete.
Click here for CTI Technical Note C1.
Chlorides in Concrete (CTI Technical Note C2)
When steel reinforcement is encased in sound dense concrete, the entire surface of the steel is covered by a stable protective oxide film that forms in the alkaline environment created by the hydration of the cement in the concrete. Under these circumstances no corrosion of the reinforcement can occur. However, if the protective oxide film is locally destroyed, areas of different potential can be set up on the surface.
There are two ways that this protective oxide film might be destroyed. These are the reduction of the pH of the concrete by carbonation and the ingress of chloride ions.
This Technical Note deals with the issue of chlorides in concrete, including threshold levels and methods of analysing for chlorides in concrete.
Click here for CTI Technical Note C2.
Electrical Continuity (CTI Technical Note C3)
This Technical Note describes CTI’s procedure for testing electrical continuity of reinforcing steel for concrete elements intended to have cathodic protection applied to them.
This procedure utilises DC reverse polarity resistance measurements and is based on AS 2832.5-2002, Cathodic Protection of metals – Part 5: Steel in concrete structures, Clause 4.2, Electrical Continuity.
Click here for CTI Technical Note C3.