FIELD EVALUATION OF THE MULTI-DEPTH DEFLECTOMETERS

The Multi-Depth Deflectometer (MDD) is an LVDT deflection measuring device which is retrofitted into pavement layers. A maximum of six MDD modules may be installed in a single 1.5 inch diameter hole. The modules are clamped against the sides of the hole at the required depths and the center core is attached to an anchor located approximately 7 feet below the pavement surface. The MDD can measure either the relative elastic deflection or the total permanent deformation of each layer in the pavement system. By placing multiple modules in a single hole, the vertical strains induced in pavement layers can be measured. This report describes the installation of Multi-Depth Deflectometers at the Texas A&M Research Annex. The pavement response under both Falling Weight Deflectometer and truck loading is described, together with an analysis procedure to backcalculate layer moduli from depth deflection readings. The MDD results obtained are extremely promising. The device is relatively inexpensive and durable. It shows a great potential in assisting in several areas of pavement research, including backcalculation analysis, tire pressure and rutting studies.

• Record URL:
  • http://tti.tamu.edu/documents/1123-2.pdf
• 
• Supplemental Notes:
  • Research study title: Nondestructive Test Procedures for Analyzing the Structural Condition of Pavements.
• Corporate Authors:

  Texas Transportation Institute

  Texas A&M University System, 1600 E Lamar Boulevard
  Arlington, TX  United States  76011

  Texas State Department of Highways & Public Transportation

  Transportation Planning Division, P.O. Box 5051
  Austin, TX  United States  78763

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Scullion, T
  • Uzan, J
  • Yazdani, J I
  • Chan, P
• Publication Date: 1988-9

Media Info

• Edition: Interim Report
• Features: Figures; References; Tables;
• Pagination: 55 p.

Subject/Index Terms

• TRT Terms: Backcalculation; Building; Costs; Deflection; Deflectometers; Deformation; Durability; Facilities; Field tests; Installation; Measurement; Modulus; Pavement layers; Pavements; Performance evaluations
• Uncontrolled Terms: Multi-depth deflectometers
• Old TRIS Terms: Pavement deflection; Vertical strains
• Subject Areas: Construction; Data and Information Technology; Design; Finance; Highways; Maintenance and Preservation; Pavements; I22: Design of Pavements, Railways and Guideways; I23: Properties of Road Surfaces;

Filing Info

• Accession Number: 00482356
• Record Type: Publication
• Report/Paper Numbers: FHWA/TX-88/1123-2, Res Rept 1123-2, TTI: 2-18-87-1123-2
• Contract Numbers: Study 2-18-87-1123
• Files: TRIS, ATRI, USDOT, STATEDOT
• Created Date: Apr 30 1989 12:00AM