Non destructive measurement of reinforcement corrosion ratein existing RC structures

摘要

The use of permanent monitoring systems to assess the corrosion of ordinaryrnreinforcement in concrete has been recognised as an important tool to preventrnpremature deterioration of reinforced concrete (RC) structures and to assist therndevelopment of reliable models that allow designing durable new structures inrnaggressive environments and to establish rational maintenance and repair strategiesrnof reinforced concrete structures affected by reinforcement corrosion.rnSeveral sensors have been proposed, in the last fifteen to twenty years, to bernembedded in concrete in order to continuously measure parameters either directly orrnindirectly related with corrosion of steel in concrete, such as: corrosion rate, openrncircuit potential, concrete resistivity, chloride content, temperature or moisturerncontent.rnThe most relevant advances in corrosion monitoring systems have been achieved inrnthe development of embedded sensors for application to new structures. For thesernstructures, sensors are embedded during concreting and the electrolytic contactrnbetween the sensor and the concrete is warranted.rnFor existing structures already affected by reinforcement corrosion, permanentrnmonitoring systems could give valuable information about long term performance ofrndifferent maintenance and repair strategies. For these structures, the sensors have tornbe fixed after concreting. The electrolytic contact between the original concrete andrnthe sensors is much more difficult to establish in a non-intrusive way and only a fewrnsystems have been proposed.rnIn this paper corrosion rate sensors, based in polarisation resistance and galvanicrncurrent corrosion measurements, specially developed to embed in existing concreternare presented and tested in the assessment of the efficiency of different concreternsurface treatments on the control of steel corrosion initiated by chlorides.