Use of advanced corrosion monitoring for risk-based management of concrete structures
R.B. Polder1, W. Peelen1, O. Klinghoffer2, J. Eri3, J. Leggedoor4
1 TNO Built Environment and Geosciences, Delft, The Netherlands
2 FORCE Technology, Brøndby, Denmark
3 Protector AS, Tranby, Norway
4 Leggedoor Beton- & Vochtweringstechniek BV, Gasselternijveen, The Netherlands
Reinforced concrete is a cost effective material used widely in our infrastructure. The durable combination of steel and concrete provides safety and serviceability. Normally, the physics and chemistry of concrete protects reinforcing steel against corrosion. Over time this protection can be lost due to aggressiveness from the environment, for example chloride ions from seawater and de-icing salts, causing corrosion. Corrosion is the main cause of damage to concrete structures. Due to ageing of the infrastructure, maintenance costs have increased to a major part of the total costs. Proper management should include taking measures for repair and re-install corrosion protection before danger occurs.
For owners of structures corrosion is difficult to handle because there are no objective tools that inform them about the corrosion state. With such information they could take remedial actions well before damage appears and their spending on repairs would be reduced.
Monitoring would allow a more cost effective management of corrosion in concrete. Monitoring systems should be based on embedded sensors for early detection of corrosion, combined with software that translates monitoring signals into the level of risk and the point in time when the structure needs repairs or other interventions.
The paper combines the domains of corrosion in concrete and sensors to monitor its progress with risk and reliability of structures. It gives an example of costs savings due to monitoring and provides underlying statistical data from the field. The ultimate goal is building software tools to design monitoring systems and sensors and to interpret signals in terms of risk of damage and to effectively and economically undertake necessary interventions.
Key words: Concrete structures, reinforcement corrosion, monitoring, risk evaluation, management