Measuring Joint Movement on Rigid Pavements Using the Traffic Speed Deflectometer

Abstract

The ability of a Traffic Speed Deflectometer (TSD) to detect joint movement on a rigid pavement was investigated. Based on a mathematical model of a moving vehicle on a concrete pavement, a method of calculating the joint displacement from a TSD measurement was developed. The joint displacement indicator was tested in practice on a concrete highway in northern Germany. Short-term repeatability, day-to-day repeatability, and reproducibility between two different TSD vehicles were evaluated based on the measurements. It was found that the TSD is able to consistently find movement at the same joints, and that the magnitude of the movement has a high short-term repeatability. Day-to-day repeatability and reproducibility between vehicles was lower due to temperature effects in the concrete slabs. However, also for these cases, there was a high level of consistency in the detected joints. Based on the distance between successive joints, a method of identifying potential locations of transverse cracks was developed. Finally, a way of quantifying joint movement in terms of spatially averaged quantities is presented.