Concrete temperature monitoring using passive wireless surface acoustic wave sensor system

In this paper, a novel nondestructive method for detecting temperature variations of concrete using a passive wireless surface acoustic wave (SAW) sensor system is described. Performance of the SAW orthogonal frequency coded (OFC) temperature sensors was evaluated in air, liquid, and concrete. To verify the response of the SAW sensor, temperature was also measured using commercially available thermocouples and compared with the extracted temperature in all environmental conditions. Analysis of the measured data showed that the SAW temperature sensor system was successful in detecting temperature over a wide range in all tested conditions with a high degree of accuracy and short interrogation time. When the sensors were embedded within a 2-in. thick concrete cover, the maximum read distance was approximately 4 m.