Wireless Strain and Temperature Monitoring in Reinforced Concrete Using Surface Acoustic Wave Sensors

Monitoring the health of civil engineering structures using implanted deformation, temperature, and corrosion sensors would further improve maintenance and extend the service life of those structures. However, sensor integration poses a number of problems due to the presence of cables and on-board electronics. Passive, wireless surface acoustic wave (SAW) sensors offer a very promising solution here. We used commercial SAW devices mounted on steel rebars to carry out an initial feasibility study. Without cables or embedded electronics, we were able to measure the deformation of a concrete beam subjected to bending load. We were also able to measure the temperature continuously over a three-week period.