Civil engineers at have developed a groundbreaking method to detect corrosion in reinforced concrete structures, offering new possibilities for designers, architects, and material innovators concerned with sustainable construction and maintenance. The solution, pioneered by ETH Zürich spin-off Talpa Inspection, uses electrochemical measurements to identify areas of corrosion without damaging the concrete. This advancement is particularly relevant for ageing infrastructure from the construction boom of the 1960s–1980s, such as retaining walls, tunnels, and bridges.

Understanding the Risks of Corrosion
Over time, chemical reactions within reinforced concrete can lead to corrosion of the embedded steel, compromising structural integrity. For retaining walls—key in stabilizing landscapes, roads, and urban designs—the stakes are high. If corroded steel goes unnoticed, walls may fail under the pressure of the earth they hold back, endangering nearby infrastructure and residents. Traditional methods to inspect reinforcing steel involve chipping away at the concrete, which is labor-intensive, costly, and only reveals localized data. With Talpa Inspection’s innovation, engineers can now monitor entire structures non-invasively through existing drainage systems, a solution particularly suited for hard-to-reach locations.

How the Technology Works
The probe developed by Talpa Inspection uses inflatable seals and electrodes, introduced into drainage pipes adjacent to the concrete structure. When the system is in place, water is pumped into the pipe, creating a conductive connection between the steel and the electrodes. This forms an electrochemical cell that measures the likelihood of corrosion based on the electrical signals produced. By taking measurements at regular intervals along a retaining wall, the team generates a comprehensive map of the steel’s condition. This approach acts as an early warning system, allowing for targeted repairs that save time, resources, and materials.

Implications for Design and Sustainability
This new method has profound implications for professionals in architecture, landscape design, and sustainable engineering. It enhances sustainability by reducing the need for widespread demolition or replacement of concrete structures, thereby preserving materials and minimizing waste. The technology also lowers costs by enabling targeted maintenance that minimizes resource use and disruption. Moreover, the non-destructive nature of the assessment aligns with circular design principles, as it facilitates ongoing monitoring without compromising material integrity. For architects and urban designers, this innovation creates new opportunities for adaptive reuse of older infrastructure, supporting efforts to achieve circularity and reduce environmental impact.

Looking Ahead
The Talpa team plans to automate the probe for widespread use, making the technology more robust and scalable. Having demonstrated success in pilot projects, the team is working towards commercialization. With over 1,000 kilometers of retaining walls in Switzerland alone requiring evaluation, the potential impact of this method is significant. By leveraging electrochemical innovation, Talpa Inspection’s approach represents a crucial step forward in ensuring the safety and durability of critical infrastructure. For professionals across design disciplines, it underscores the importance of material research in creating more resilient and sustainable urban environments.

Source: ETH Zürich
Photos: ETH Zürich