Improved Testing Speed of the Rolling Dynamic Deflectometer

The Rolling Dynamic Deflectometer (RDD) was developed by the researchers at The University of Texas at Austin in the late 1990s. It has been used in many project-level pavement studies in Texas. The current testing speed of the RDD is limited to 1 mph (1.6 km/hr) using first-generation rolling sensors. This Texas Department of Transportation (TxDOT) research project 0-4357 was initiated to further develop the RDD. The primary objective of this project is to design and build second-generation rolling sensors, which will triple the current RDD testing speed from 1 mph (1.6 km/hr) to 3 mph (4.8 km/hr). Four second-generation rolling sensors were designed, built and calibrated in the laboratory. Based on the results collected during two field trials at the Pickle Research Campus, it was found that the second-generation rolling sensors can readily achieve the testing speed of 3 mph (4.8 km/hr). In terms of rolling noise characteristics, this new rolling sensor has lower rolling noise than the first-generation rolling sensor.