True Road Surface Deflection Measuring Device

The high-speed measurement of accurate pavement surface deflections under a moving wheel on the Texas roadway network (network level) still remains a challenge in pavement engineering. This goal cannot be accomplished with stationary deflection-measuring devices, such as the falling weight deflectometer (FWD); nor with slow-moving (< 2 mph) and discontinuous profiling, such as the LaCroix deflectograph; nor with slow-moving (< 3 mph) but continuous profiling devices, such as the rolling dynamic deflectometer (RDD) or total pavement acceptance device (TPA D). Today, network level studies of pavement structure are being performed with three moving devices: the Curviameter, which travels at about I l mph and employs stationary geophones to continuously measure pavement deflections; and the rolling wheel deflectometer (RWD) and traffic speed deflectometer (TSD), which travel at 40 mph to 60 mph and use laser-based sensors to continuously measure pavement deflections. The major limitation with the RWD and TSD is the lack of accurate measurements due to pavement texture and roughness, which leads to determination of average deflections over 50 ft. or more. That is, no true deflection is measured at any point; it is only an indicative measurement. The measurement accuracy of the Curviameter is high, but the complexity of the continuous chain mechanism to locate the geophones inhibits improvements in testing speed and continuity of measurements. The Work conducted in this research project shall be for Phase 1 only. The Performing Agency (hereafter referred to as the "Research Team") shall develop in this Phase I a device for measuring true surface deflections at network level. The development of this device is based on extensive experience of the Research Team with non-destructive testing (NDT) technologies and also on recent advances over the past several decades in sensor technologies that can be applied to continuous deflection measurements. These advances include the developments of low-frequency accelerometers and wireless Bluetooth technology. Pavement deflections under a fully loaded full-scale axle will be measured by sensors that are wireless and stationary on the pavement. This will eliminate the negative effects of pavement texture and roughness, and permit accurate measurements.


  • English


  • Status: Active
  • Funding: $2,910,493
  • Contract Numbers:


  • Sponsor Organizations:

    Texas Department of Transportation

    125 E. 11th Street
    Austin, TX  United States  78701-2483
  • Project Managers:

    Odell, Wade

  • Performing Organizations:

    University of Texas, Austin

    Center for Transportation Research
    3925 W. Braker Lane, 4th Floor
    Austin, TX  United States  78759
  • Principal Investigators:

    Prozzi, Jorge

  • Start Date: 20150408
  • Expected Completion Date: 20190228
  • Actual Completion Date: 0
  • Source Data: RiP Project 39976

Subject/Index Terms

Filing Info

  • Accession Number: 01569090
  • Record Type: Research project
  • Source Agency: Texas Department of Transportation
  • Contract Numbers: 0-6873
  • Files: RiP, STATEDOT
  • Created Date: Jul 1 2015 2:46AM