Sensor systems for use in reinforced concrete structures

Whole-life costing and residual service-life prediction of structures require quantitative information on cover-zone properties and threshold values for corrosion initiation and, once initiated, the rate of corrosion. It is clear that there exists a need to determine those near-surface characteristics of concrete, which promote the ingress of gases and liquids containing dissolved contaminants. In addition, in-situ monitoring of the seasonal change in such properties could assist in making realistic predictions as to the in-service performance of the structure, likely deterioration rates for a particular exposure condition, or compliance with the specified design life. To this end, this paper presents a review of sensors and associated monitoring systems from which information concerning corrosion activity, concrete (electrical) resistivity, oxygen availability, carbonation and chloride ingress can be obtained at strategic locations within a structure. This paper is based upon a draft of a RILEM Technical Recommendation 'Measurements with embedded sensors' prepared for RILEM Technical Committee TC-154 'Electrochemical methods for measuring metallic corrosion in concrete'. The work also formed part of the European research programme COST 521 - 'The Corrosion of Steel in Reinforced Concrete Structures'. (C) 2004 Elsevier Ltd. All rights reserved.