Corrosion Inhibitor Systems for Rebar in Concrete Structures

The performance of two types of corrosion inhibitor systems that can be brushed and sprayed applied to reinforced concrete to protect rebar has been evaluated at 2 military facilities in Okinawa. The two systems were: (1) a three-component corrosion inhibitor comprised of an inorganic migratory corrosion inhibitor, an organic vapor phase migratory corrosion inhibitor, and a reactive silicone surface protection agent, and (2) a NASA developed cathodic coating system composed of an inorganic silicate vehicle containing zinc, aluminum, magnesium and indium metal powders, applied to a reinforced concrete surface along with titanium mesh strips that are connected to the rebar to conduct the coating produced cathodic current. The systems were evaluated on a fuel patrol culvert bridge, and on separate beam girders in a warehouse. 

The project results show that properly selected and applied migratory corrosion inhibitors or sacrificial cathodic coating systems can be successfully used to extend the life of reinforced concrete structures.  These technologies demonstrated the capability of reducing the measured corrosion rate by a factor of two to three at Okinawa. Water permeation rates were also significantly reduced. The causes of the rebar corrosion, apllication procedures, details of measurements before and after inhibitor application will be discussed.