DEVELOPMENT AND PRELIMINARY INVESTIGATION OF A ROLLING DYNAMIC DEFLECTOMETER. INTERIM REPORT

A Rolling Dynamic Deflectometer (RDD) has been developed by making modifications to a vibroseis truck. The RDD can make continuous profiles of pavement flexibility or stiffness can be measured under heavy loads. The RDD employs a servo-hydraulic vibrator to apply static hold-down and vertical dynamic forces to two sets of dual loading wheels. A total force (static plus dynamic) of 150 kN (33,000 lb) can be applied to the pavement surface while the RDD is moving at velocities of 3 to 6 km/h (2 to 4 mph). Dynamic deflections of the surface are continuously recorded with an accelerometer located on a set of receiver wheels positioned mid-way between the loading wheels. The loading and monitoring systems of the RDD have been calibrated, and initial testing has been performed at the Texas Transportation Institute (TTI) pavement test facility. Eight flexible pavement sections, covering a range in flexibility, have been successfully tested. Loading frequencies of 22 and 40 Hz have been used with a wide range in dynamic loads. The RDD was able to make measurements of: longitudinal variability within each section, differences in flexibility between sections, and nonlinearities in flexibility at several sections. Finally, a comparison between RDD and FWD measurements show the flexibilities measured by both methods are consistent with each other, and closely related.

• Supplemental Notes:
  • Research study title: Automated Equipment for Characterizing the Properties and Thicknesses of Pavements.
• Corporate Authors:

  University of Texas, Austin

  Center for Transportation Research, 3208 Red River Street
  Austin, TX  United States  78705

  Texas Department of Transportation

  Research and Technology Transfer Office, P.O. Box 5051
  Austin, TX  United States  78763-5051

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Stokoe II, K H
  • Bay, J A
• Publication Date: 1995-9

Language

• English

Media Info

• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 72 p.

Subject/Index Terms

• TRT Terms: Alternatives analysis; Deflection; Deflectometers; Falling weight deflectometers; Flexibility; Flexible pavements; Nondestructive tests; Pavements
• Uncontrolled Terms: Rolling dynamic deflectometers
• Old TRIS Terms: Pavement deflection
• Subject Areas: Highways; Pavements; I23: Properties of Road Surfaces;

Filing Info

• Accession Number: 00720269
• Record Type: Publication
• Report/Paper Numbers: FHWA/TX-95-1243-3, Res Rept 1243-3, CTR 0-1243-3
• Contract Numbers: Study 0-1243
• Files: TRIS, USDOT, STATEDOT
• Created Date: Apr 24 1996 12:00AM