Improved in-road sensing device for pavement health monitoring using IOT

Abstract

Continuous pavement health monitoring enables the detection of early degradation of pavement structures, thereby extending the lifetime of roads by informing predictive maintenance actions. A previous paper described a method that enables low cost, high coverage, and continuous monitoring of the displacement, temperature, humidity and moisture content of pavement structures. The pavement condition outcomes are communicated to a hub using a LoRa sensor network that combines long read range, low power consumption and sufficient communication speed, while a solar cell and battery provide continuous power to allow 24/7 operation even in dense traffic conditions. This paper reports on the development and evaluation of an improved version of this system. The number of accelerometers was increased from one to four to allow assessment of pavement condition at different depths below the surface. The on-board software was extended to allow the capturing of measurements to be automatically triggered either by a magnetometer, that senses the presence of large metal objects, or by using the acceleration signal itself, implementing a sliding window to prevent the loss of data captured before the trigger threshold is exceeded. The displacements derived from acceleration measurements were compared against LVDT-based displacement measurements and found to be accurate within a few percent. The LoRa sensor network allows the real-time communication of selected features like peak signal amplitude, as well as the communication of detailed measurements during quiet times to allow the impact of heavy vehicles to be characterised in detail.