Development and evaluation of piezoelectric ceramic-polymer composite sensors for weigh-in-motion applications

Abstract

This research explored the development and implementation of a novel, durable, higher voltage, and lower temperature dependant weigh-in-motion (WIM) sensor. These better sensors will require fewer lane closings and replacements than existing sensors. They will also aid the Departments of Transportation to better identify those vehicles that do not comply with the current weight restrictions. The primary focus of the research was to create a full scale WIM sensor that is less temperature dependent and more durable than traditional WIM sensors. Traditionally, the data collected from the sensor may be utilized in two ways. The first is by using static vehicle effects on the sensor, which corresponds to the weight of the vehicle, this data can be used for enforcement of the vehicle legal weight limits. The second is by using the dynamic loading of the sensor, which relates to the actual loading that the roadway is experiencing, this data will be useful to engineers who must design the roadway as well as plan for repair schedules. In addition, instead of just using WIM data to screen commercial vehicles or for pavement design; there is a new recognition that good data can be useful for bridge structural analysis, safety analysis, traffic control and operations, freight management and operations, facility planning and programming, and standards and policy enforcement as per the recent report "Effective Use of Weigh-in-Motion Data, the Netherlands Case Study" FHWA October 2007. In lieu of this development, the need for better sensors to provide good data is more important today than ever before. The ceramic-polymer composite sensors performed extremely well in all laboratory testing. However, under full-scale field implementation, a rather aggressive goal, the sensors and sensor assemblies experienced some level of failure. During the forensic evaluation it was found that that the pavement section for the full-scale testing was already quite old and significantly fatigued. Therefore, the test site was prone to fail almost immediately after installation. Discounting the results of the full-scale field testing, the PZT-5H ceramic-polymer composite sensor performed with less variability due to temperature and produced higher voltage output than standard PVDF materials.