Network Level Structural Evaluation With Rolling Wheel Deflectometer

One of the primary purposes of pavement management systems (PMS's) is to select maintenance and rehabilitation (M&R) treatments at the optimum time during the life of each pavement in a network of roads. The M&R selections are typically based on surface condition and other available historical data. Surface distress data provides a good indication of the functional condition of a pavement and some distresses (example - alligator cracking) provide an indication of structural problems. However, assignment of M&R treatments could be improved if pavement structural capacity was considered in the evaluations. A falling weight deflectometer (FWD) is a common non-destructive testing tool used to assess structural capacity of pavements. However, the relatively slow rate of testing and the need for traffic control often precludes its use on a broad network level. In response to the need for rapid collection of structural data on a network level, the Rolling Wheel Deflectometer (RWD) was developed. The RWD is an innovative device that uses a series of lasers mounted beneath the bed of a custom-built 53-foot (16 meter) semi-trailer to measure a continuous profile of pavement deflections under the trailer's 18-kip (8,164 kg) single axle load while traveling at traffic speed. This paper presents the results of a study that evaluated the structural capacity of a sampling of the Pennsylvania Department of Transportation's (PennDOT's) roads using the RWD and compares the results to other conventional methods. The use of structural data from the RWD for network level PMS is also demonstrated through the study.