Demonstration of a New, Multi-Function, Nondestructive Pavement Testing Device

The rolling dynamic deflectometer (RDD) was originally developed through the Texas Department of Transportation (TxDOT) research program to determine continuous deflection profiles that are used in pavement structural assessments. TxDOT researchers have shown that RDD deflection profiles can be used more effectively when combined with other data such as pavement thickness and subsurface conditions. Therefore, TxDOT has supported development of a multi-function device which is equipped with RDD profiling and ground penetrating radar (GPR) functions. Additional functions that have been integrated into the new device are video cameras for pavement and right-of-way conditions, pavement temperature measurements and high-precision positioning. These multi-functions permit efficient comparisons of RDD deflection data with other nondestructive testing (NDT) data logged by the different methods. The new device is called the Total Pavement Acceptance Device (TPAD). The TPAD has all functions combined on a single platform that can move along the pavement at 2 to 3 mph. All measurements are collected in a single pass and analysis software permits the data to be displayed in near-real time (less than 5 minutes after collection) so that the results can be used for preliminary evaluations of pavement conditions on-the-fly or can be used for more detailed analyses at a later time. In this paper, a background on two of the nondestructive testing functions in the TPAD, the RDD and GPR systems, are briefly discussed. A description of the TPAD mobile platform and the RDD dynamic loading system are described. The developmental work for the speed-improved rolling sensors is also discussed. Finally, the TPAD is demonstrated by presenting RDD deflection profiles and GPR records collected at a testbed created at the TxDOT Flight Services Facility (FSF) are presented.