Colours reveal where material will crack
February 13, 2025 – Many tunnels and bridges are over 50 years old and approaching the end of their service life. The failure of such structures poses a serious risk, as demonstrated by the 2018 collapse of the Morandi Bridge in Genoa, which resulted in 43 deaths and 16 injuries. Identifying material cracks in a timely manner is therefore crucial.
Researchers from the University of Luxembourg and the Technical University of Darmstadt have developed a specialized coating that detects potential cracks in concrete. According to the scientists, this technology is cost-effective, scalable, and has the potential to significantly improve the safety of essential infrastructure such as bridges and dams.
The Luxembourg method involves applying a thin layer of Cholesteric Liquid Crystal Elastomers (CLCEs)—materials that change colour in response to changes in the structure’s condition. The coating can also track the progression of cracks, enabling early intervention before structural failure occurs.
The research team is currently refining the chemical composition of CLCEs to allow for customized colour changes or even invisibility until a crack forms. Although originally designed for concrete, the technology could easily be adapted for use on metal surfaces, such as those found on airplanes, boats, trains, and cars.
This research was previously published in the journal Structural Health Monitoring under the title ‘Optical Crack Detection and Assessment Using Cholesteric Liquid Crystal Elastomers.’
