Sika® FerroGard®-520 Patch is a zinc based discrete sacrificial anode placed inside a concrete repaired area in reinforced concrete structures which are corroding as a result of chloride ingress and / or carbonation. Sika® FerroGard®-520 Patch anodes are placed along the perimeter of the repair area and fixed to the reinforcement prior to the application of a concrete repair system. The reinforcement outside the repaired area is at greatest corrosion risk owing to the passive condition of the reinforcement within the repaired area. Sika® FerroGard®-520 Patch anodes corrode preferentially to the surrounding reinforcement offering protection against incipient corrosion damage. In addition, standard repair mortars, bonding primers and reinforcement corrosion protection coatings can be used as Sika® FerroGard®-520 Patch is placed in the parent concrete and not within the repair mortar.