Development and evaluation of cement/emulsified-asphalt based piezoelectric sensors for road weigh-in-motion system

Piezoelectric composites (PCs) have great potential in traffic information perception. In this study, 2–2 cement/emulsified asphalt PCs were prepared by the cutting-filling method, and a set of preparation technology was formed. The finite element model of PC and road structure was established to simulate the loading process of moving load, and the influence of embedded PCs on road structure was further discussed. In addition, the effects of the buried depth and offset distance of PCs on the mechanical electrical effect were studied. The results indicated that the buried depth had a little effect on the mechanical electrical effect of PCs, and this effect would be amplified when the load was close to the buried position: the shallower the PCs were buried, the greater the output voltage. When the load was in the direct-acting zone, the voltage output curve was a multi-peak curve, and the attenuation of the voltage peak with the offset distance was small; when the load was in the indirect-acting zone, the output curve was a single peak curve, and the output voltage decayed rapidly with the increase of the offset distance. It was found that the load level was linearly related to the voltage peak value, and the high-precision axle load detection could be achieved by embedding PCs in the road, so as to realize the weigh-in-motion of the road.