Abstract: Cathodic protection of an existing concrete structure, including a steel member at least partly buried, such as steel rebar, in the concrete structure, is provided by embedding anodes into a fresh concrete layer applied over an excavated patch and/or as a covering overlay. The anodes are embedded at spaced positions or as an array in the layer and connected to the rebar. A reinforcing layer is applied to the anode or adjacent the anode to resist expansion of the anode body tending to cause cracking of the concrete caused by the larger volume of the corrosion products relative to the anode material. Pores are provided in the anode body so as to take up the corrosion products. The reinforcing layer can be provided in the actual anode body as a closed surface surrounding the anode material inside or may be provided in the concrete as a layer on top of the anode in an array form at or near the outer surface of the concrete.

Abstract: Restoration of a concrete roadway is effected by application onto the upper surface of the roadway of steel sheets which are used as an anode for electrolytic transfer of ions between the anode and the reinforcing bars of the concrete as cathode. The steel sheets are placed in effect directly on top of the concrete surface so as to communicate forces from the traffic to the concrete surface without the necessity for separate support of the sheets. An intervening layer may be formed of particulate material, a very thin felt or there may be no intervening layer. The sheets can be formed by two layers of steel with the upper layer embossed and the edges offset so as to define flanges allowing the sheets to be bolted together. A covering wear layer such as asphalt can be applied on top of the sheets.

Abstract: An electrolytic restoration of concrete includes an anode positioned at a surface of the concrete to be restored and the communication of a current from the anode to the reinforcing bars in the concrete as a cathode. The anode is in the presence of or carries an electrolyte so that sufficient current is provided temporarily over a sufficient period of time so that ions from the concrete are carried through the concrete and expelled into the electrolyte for extraction. The anode is provided by layer of conductive material which is particulate or fibrous so that it is an amorphous layer which can therefore follow the surface of the concrete. In a horizontal arrangement, the layer can be applied directly onto a felt mat for carrying electrolyte.