Half-cell potential mapping can detect chloride induced corrosion of the reinforcement in a very early state. The combination with a Vortex climbing robot allows access to any concrete surface.
Corrosion of the reinforcing steel adversely affects durability and safety of our infrastructure (bridges, power plants or buildings) with huge annual costs. In the US 325 – 1000 Mio (2000), in the UK 550 Mio were attributed to corrosion of reinforced concrete structures. In Switzerland detailed costs are reported for repair and maintenance of the national highway system, showing an increase from 249 Mio (1995) to 768 Mio (2010).
While corrosion of the reinforcing steel might not be the sole cause of all repair work, it is a significant contributor. A timely detection of corrosion thus could greatly reduce the costs of repair interventions. All reinforced concrete structures have to be regularly inspected. As a rule these inspections are performed visually, thus the main problem, corrosion of the reinforcement, can be detected only when it manifests at the surface by cracking, rust or spalling. Using the half-cell potential mapping technique, corrosion can be detected in a very early stage, allowing interventions with lower cost. However, a direct access to the concrete surface is necessary – and this is for many structures very difficult and/or very expensive.
On the other side, climbing robots using the Vortex technology are able to adhere to vertical, inclined or even underside concrete surfaces. In collaboration with the Autonomous System Lab (ASL) of ETH Zurich the two state-of the art technologies have been combined and a climbing robot for corrosion monitoring of reinforced concrete structures has been developed. Tests in the laboratory and on real structures have proven the feasability of this new approach. Watch the video.
