Improved testing speed and rolling noise estimation in rolling dynamic deflectometer testing

The Rolling Dynamic Deflectometer (RDD) is a state-of-the-art device that has been used in project-level pavement studies to measure continuous deflection profiles along both highway and airport pavements. Because the RDD deflection measurements are made using contact rolling sensors, the physical and rolling-noise characteristics of the sensors limit the maximum RDD testing speed. In this paper, a two-part study is presented to improve the RDD testing speed and characterization of rolling noise. The first part involves development of second-generation rolling sensors. Field trials using the second-generation rolling sensors on a flexible pavement show significant improvements in testing speed and rolling-noise minimization. The second part involves improving the understanding of the noise that is simultaneously collected with the input RDD signal. This noise is referred to as rolling noise. This effort was achieved by analyzing RDD data collected from numerous project-level studies that involved different deflection levels, pavement surface roughnesses, and testing speeds. These data allowed development of a generalized rolling-noise envelope.