In the case of steel reinforced concrete, the concrete bestows a double means of protection against corrosion on the embedded reinfor-cement of unalloyed steel . The steel is passivated by the highly alkaline pore electrolyte and the concrete cover, due to its low permeability for gases and aqueous solutions, prevents the active agent necessary for corrosion from reaching the embedded steel. Reinforced concrete structures are nonetheless neither of unlimited durability nor free from maintenance requirements. In cases of carbonation of the concrete cover or chloride ingress, reinforcement steel corrosion and concrete spalling may be expected. Also, where stringent requirements for construction component safety are defined, it makes sense both technically and economically to utilise additional protective measures against corrosion.