Wireless cement-based sensor for self-monitoring of railway concrete infrastructures

In this study, we developed a cement-based wireless sensing system for self-monitoring of concrete infrastructures in a railway environment. The cement-based sensor was developed by inserting electrodes into cement composites incorporating 1.0 vol% multi-walled carbon nanotubes (MWCNTs) as conductive fillers. We designed and fabricated a wireless signal transmission module that can be mounted/dismounted directly on/from the cement-based sensor and a wireless reception module that receives and saves wireless sensor signals. The wireless transmission/reception module was applied to the cement-based sensor, and sensing response during the cyclic compression test was compared with that in a wired environment. The sensing response and the gauge factor in the wireless environment were found to be very similar to those in the wired environment. The loss rate of wireless transmission data was tested according to the distance between the transmitter and the receiver to determine applicability in an actual railway environment. Based on the test results, the distance of stable wireless transmission was evaluated for the open space, railway station, and railway sleeper. When the developed cement-based wireless sensor is applied to the railway sleeper, the wireless sensing system is expected to be used up to 3.5 years when the battery needs to be replaced.