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Advanced fiber-optic sensors monitor for corrosive conditions in concrete
Innovative fiber-optic sensors that
detect corrosion-inducing conditions in steel-reinforced concrete are being devel- oped by researchers with City University London (London, United Kingdom) and Queen's University Belfast (Belfast, United Kingdom) with funding from the Engineering and Physical Sciences Re- search Council (EPSRC) (Swindon, United Kingdom). Designed for longer- term sustainability within concrete, the sensors are intended to safely and effec- tively monitor existing concrete structures such as bridges and other infrastructure, particularly in tidal and splash zone areas where continual wetting and drying of the concrete increase the corrosion risk of the embedded steel rebar. So far the research has shown real promise in terms of over- coming current sensor technology limita- tions, especially for sensing range, sensi- tivity, and durability. At the heart of the four-year research
XZWRMK\ Q[ I [MZQM[ WN IL^IVKML ÅJMZ WX\QK sensors that measure temperature, hu- midity, pH, and chloride levels. Accord- ing to Tong Sun, professor of sensor en- gineering at City University London and principal investigator on the project, concrete is highly alkaline with a very high pH (a value of 12 or higher), which can degrade traditional sensor probes and limit their longevity. To address the deg- radation problem, the researchers have incorporated polymers into the design IVL NIJZQKI\QWV WN \PM ÅJMZ WX\QK [MV[WZ[ which make them much more resistant to highly alkaline environments as well as responsive to chemical changes in an environment. .QJMZ WX\QK [MV[WZ[ ][M WX\QKIT ÅJMZ
to sense changes in an environment and relay measurement information from a sensor to an interrogation device for processing. Typically, the sensors in a ÅJMZ WX\QK [MV[WZ [a[\MU IZM IK\Q^I\ML by light sent from an optical light source \PZW]OP I \PQV OTI[[ WX\QKIT ÅJMZ
Innovative fiber-optic sensors developed by researchers with City University London and Queen's University Belfast will detect corrosion-inducing conditions in steel-reinforced concrete structures such as bridges. Photo by Graham Soult.