Transition of the Rolling Dynamic Deflectometer Device from a Screening Tool to an Evaluation Tool for Rigid Airfield Pavement Projects

For the past decade, the rolling dynamic deflectometer (RDD), a continuous deflection measurement device, has been used as a screening tool in identifying problematic airport pavements for repair. The RDD has not seen much use, however, as an evaluation tool to measure characteristics such as moduli of pavement layers and load-transfer efficiency (LTE). The primary goal of this research was to develop the hardware and software to take the RDD from a screening tool to an evaluation tool for airport pavement projects. In this study, the RDD as an evaluation tool could obtain (a) continuous measurement of rolling deflection basins (for the backcalculation of layer moduli to be studied) and (b) continuous evaluation of joint LTEs. Four subtasks were conducted: (a) investigation of parameters affecting the RDD measurements, (b) use of an increased number of rolling sensors, (c) improvement of RDD data processing (distance-based deflection profile with increased spatial resolution), and (d) a series of field tests with the RDD on a rigid airfield pavement. With all five sensors continuously monitored during rolling, the software that was developed was capable of selecting a zone of lateral uniformity over which it was appropriate to construct deflection basins. The improved data processing identified accurate locations of joints and properly positioned two rolling sensors on opposite sides of the adjacent slabs in the continuous deflection profile, producing a continuous LTE evaluation along the pavement. The RDD measurements (continuous deflection basins and LTEs) were compared with falling weight deflectometer measurements, and the comparison provided promising results.