ABSTRACT
Chloride induced corrosion of reinforcement is a growing problem due to aging of concrete structures exposed to deicing and marine salts. Increased numbers of structures need repair of damage and protection against chloride induced corrosion [Polder et al. 2012]. The majority of repairs follow the conventional method: removal of chloride contaminated concrete, cleaning of the steel to bright metal and application of new concrete [EN 1504-10]. In practice, conventional repairs have poor durability and their life appears limited: according to a European survey, about 50% of repairs fail within ten years [Tilly & Jacobs, 2007; Tilly, 2011]; similar observations were made in a Dutch study [Visser & Zon 2012]. Failure of conventional repairs is due to various mechanisms. Corrosion related factors of repair failures are: insufficient removal of contaminated concrete; insufficient cleaning of affected reinforcing steel; and electrochemical effects (incipient anode or “patching” effects) between repaired and surrounding non-repaired places where chlorides are present. In such cases, the chlorides left behind in concrete, corrosion products, and corrosion pits reactivate the corrosion process Consequently, the loss of steel cross section continues and new cracking results, necessitating new repairs.
