A Comparison of the Rolling Weight Deflectometer with the Falling Weight Deflectometer

摘要

A prototype Rolling Weight Deflectometer (RWD) has been designed and produced for testing airfield pavements. The RWD is a trailer mounted device that continuously measures maximum pavement deflections under a load wheel under moving conditions. The RWD was originally designed to perform measurements at a maximum speed of 10 kph (6 mph) with load of up to 222 kN (50,000 lb.). The RWD was recently modified to collect deflections at an increased speed of 32 kph (20 mph) under a 40 kN (9000 lb.) wheel load. It is anticipated that a highway version of the RWD will be produced jointly by Quest Integrated and Dynatest Consulting, Inc., within the next two years that will collect deflections at highway speeds of 70 to 80 kph (45 to 50 mph). In September of 1997, the Washington State Department of Transportation completed a test comparing the deflection results from the RWD and the WSDOT FWD. The testing was conducted on a newly constructed roadway that consisted of 165 mm (6.5 inches) of asphalt concrete over 400 mm (16 inches) of crushed stone base. At the time of testing the roadway had received only construction traffic. The RWD produced deflections that compared closely with the Falling Weight Deflectometer both in magnitude and variation along the highway. The results of this comparison test are documented in the paper.