Project: Tunnel Rehabilitation Project

Location: Germany

Date: July 2014

Client: State Contracting Authority/ State Enterprise

Initial situation:

As a result of operational retrofitting work, the operators of the motorway tunnel detected chlorides in the portal area, which made it necessary to rehabilitate the concrete of the tunnel walls.

The rehabilitation aimed to reduce the costs of the necessary repair measures and to observe the residual risk (chlorides remaining in the structure) and the effectiveness of the surface protection systems used over a very long period.



Installation of a monitoring system that evaluates and prevents a potential residual risk after the gradual removal of the chloride-contaminated concrete layer, and at the same time,  to evaluate the effectiveness of the surface protection in the long run.

Corrodec©2G sensors, a cable- and energy-free corrosion and moisture monitoring system, were installed in the portal tunnel areas to ensure the safety of the structure.

The data was read out manually using a hand-held reader and remotely (via GPRS) to visualize the information. The status of the sensors can thus be queried remotely at any time.

Version 1 – Manual reading (Handheld device)

In addition, the condition of the sensors can be determined directly on-site by means of a hand-held reader within the scope of the maintenance intervals customary for the building.

Version 2 – Automatic remote reading (via Internet)

Added value:

  • Uncomplicated visualization of the building condition
  • Cost reduction in concrete repair – less removal or SPCC
  • Proof of repair success
  • Differentiated repair in case of OS system failure
  • Targeted control of inspection intervals by remote query
  • Standard-compliant work with the applied “W” repair principle
  • Reduced blocking times for subsequent repairs

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