Talpa detects corrosion in reinforced concrete

(CONNECT) Researchers at the Swiss Federal Institute of Technology in Zurich (ETH) have developed a method for detecting corrosion in the reinforcing steel of reinforced concrete structures without having to break open the concrete. The method developed by mechanical engineer Lukas Bircher and his team is based on electrochemical measurements, the ETH reported in a press release. Specifically, the researchers have invented a probe consisting of two inflatable seals with electrodes in the middle. A water pipe is installed in the associated cable.

The probe is inserted into the drainage pipes, the seals are inflated and then water is introduced into the sealed area. The water creates a connection between the electrodes in the probe and the soil through the holes in the drainage pipe. This creates an electrolytically conductive connection to the steel in the structure, which forms a local electrochemical measuring point. "We use the measuring cell to record electrical signals, which vary depending on whether the reinforcing steel is corroded or not," Bircher is quoted as saying in the press release.

At present, the probe still has to be passed manually through the drainage pipes one by one to enable a comprehensive assessment of the condition of the steel. In the next step, the team wants to "automate the measurement more and make the inspection probe more robust", explains Bircher. As the concept has already proven its worth, he will found a start-up called Talpa-Inspection together with materials engineer Federico Martinelli-Orlando and civil engineer Patrick Pfändler. ce/hs