This paper summarizes 1995 through 1998 laboratory, outdoor exposure facility, and field data on the subject concrete “rehab” system. The system shows promise as a means of providing cathodic protection to the reinforcing, as a chloride removal process, as a re-alkalization process, and/or as a lithium injection procedure to minimize alkali-aggregate reactions in the concrete. Unique characteristics of the system include:
1. Surrounding each galvanic anode with a highly corrosive liquid which maintains it (the anode) at peak output voltage throughout its life; and
2. Placing an ionic transfer layer between the anode and the concrete surface that is high volume, low resistivity and deliquescent (i.e. pulls water vapor out of the air at relative humidities of 35% or higher). The ionic transfer layer typically consists of sponge, felt or sand “loaded” with calcium chloride (and/or other chemicals such as sodium hydroxide,
potassium acetate, and lithium-salts). In some cases it also contains a “wetting agent” and is encapsulated (fully or partially) in vapor permeable, but water impermeable materials. The ionic transfer layer will not freeze at temperatures as low as -20 °C (–5 °F), and provides sufficient space for all anode corrosion products, thus preventing undesirable stresses on the concrete, the anode assembly and any cosmetic covering.
Keywords: Anode, Galvanic, Cathodic Protection, Corrosion, Concrete, Deliquescent, Humectant.