European Metro – Concrete tunnel corrosion monitoring case study
The European Metro project, a pivotal part of Scandinavian’s transport system, required a comprehensive strategy for monitoring the durability of its concrete structures, particularly in areas susceptible to corrosion. To address this, a sophisticated approach was employed using ConcreteIntel Probe Sensors, and instrumentation DAUs (Data Acquisition Units).
Sensor Placement and Configuration
ConcreteIntel Probe Sensors were meticulously installed on rebar cages at designated locations before the concrete pour. The placement was executed with tight tolerances to ensure accuracy. The sensors were positioned with the outer anode set at a depth of 20 mm below the concrete surface and the inner anode aligned with the outer layer of the rebar cage.
Measurement Techniques
The ConcreteIntel Probe Sensors facilitated a complex series of electrochemical measurements between individual anode elements and the cathode. These measurements spanned various parameters including:
- Current: nanoamperes (nA) to milliamperes (mA)
- Voltage: microvolts (µV) to volts (V)
- Resistance: ohms (Ω) to kilohms (kΩ)
A reference electrode was employed to control these measurements accurately. To mitigate disturbances caused by the measurement process, time intervals were set to allow the anode and cathode surfaces to re-stabilise between measurements. This procedure ensured the reliability of the data collected.
Data Collection and Analysis
Each measurement cycle produced multiple data sets. These data were instrumental in refining uncertainties and assumptions within service life models, particularly concerning chloride diffusion. The integration of real-time data into these models allowed for re-calibration, enhancing the confidence in life predictions and reducing the risks associated with future asset conditions.
Results
The implementation of ConcreteIntel Probe Sensors enabled:
- Enhanced Accuracy: The detailed electrochemical measurements provided precise insights into the concrete’s condition and corrosion potential.
- Improved Service Life Models: The data collected allowed for accurate re-calibration of service life models, improving predictions about the infrastructure’s longevity.
- Reduced Risk: By refining the understanding of chloride diffusion and other corrosion factors, the approach significantly mitigated future asset condition risks.
The use of ConcreteIntel Probe Sensors for concrete tunnel corrosion monitoring in the European Metro project exemplifies a robust method for ensuring infrastructure resilience. By leveraging advanced electrochemical measurement techniques and integrating real-time data into service life models, the project successfully enhanced the reliability and safety of the Scandinavian’s critical transport infrastructure. This proactive approach not only improved the confidence in longevity predictions but also contributed to the effective management and maintenance of the metro system.
If you are considering implementing or updating your concrete tunnel corrosion monitoring strategy, get in touch. Email us: info@precisionstructuralhealthsensors.com. to schedule a consultation with one of our expert engineers. At Precision Structural Health Monitoring Sensors, we provide end-to-end support— from design through implementation to ongoing support—offering customized SHM solutions tailored to meet your specific requirements.
