Sensing skin made from TPE can detect concrete cracks

ERJ staff report (DS)

Potsdam, Germany -- Civil engineers at the University of Potsdam in Germany and MIT in the US, recently proposed a new method for continual electronic monitoring of concrete structures based on a flexible TPE skin.

In papers appearing in Structural Control Health Monitoring (December 2010) and the Journal of Materials Chemistry (April 2011), the researchers describe a flexible fabric with electrical properties that could adhere to areas prone to cracking - such as the undersides of bridges - and detect cracks almost immediately when they occur.

The researchers originally tested their idea using a commercially available, inexpensive stretchy silicon fabric with silver electrodes. While this worked in some lab experiments performed on both small and large concrete beams under stress, the material ultimately proved too thin and flexible for this application. The researchers have now developed a prototype sensing skin made of soft stretchy thermoplastic elastomer mixed with titanium dioxide that is highly sensitive to cracks; painted patches of black carbon measure changes in the electrical charge of the skin. A patent for the sensing method has been filed.

“The sensing skin has the remarkable advantage of being able to both sense a change in the general performance of the structure and also know the damage location at a pre-defined level of precision,” said Dr. Simon Laflamme, who did this research as a graduate student in MIT CEE. “Such automation in the health-monitoring process could result in great cost savings and more sustainable infrastructures.” Laflamme worked with CEE Professor Jerome Connor and University of Potsdam researchers Guggi Kofod and Matthias Kollosche.

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Press release from MIT