Using Ground Penetrating Radar for Evaluation of Asphalt Density Measurements

The objective of the study was to determine the practicality of using ground penetrating radar (GPR) based devices for post-construction hot mix asphalt (HMA) density measurements. Non-nuclear density measurement techniques such as GPR are of interest to state highway agencies as substitutes to nuclear gauges primarily for safety concerns and to eliminate costs associated with radioactive material licensing. In addition, GPR has the ability to obtain 100% coverage of the section being tested. The work on this project was carried out using the Florida Department of Transportation (FDOT) 2.0 GHz Horn Antenna GPR system, and included an assessment of its capabilities and limitations, and determination of optimal operational parameters for asphalt density measurement. Key elements of this work were the implementation of automated software for processing the GPR data and a laser trigger system to automatically mark the start and end of the GPR survey sections. A GPR survey protocol, established from test track surveys at FDOT's state materials office test facility, was applied to the field validation trials. An initial field trial was completed as part of a construction project on SR 20, near the Town of Interlachen, Florida. A total of four different sections were selected for surveying as part of the study, with an extended survey section, which included two of the sections previously surveyed. In each of the four sections surveyed, the GPR dielectric data was determined on-site and used to locate pavement core locations. The pavement cores were extracted by the FDOT State Materials Office (SMO), and tested for Bulk Specific Gravities (Gmb). The GPR dielectric constant values were correlated to the laboratory test results (Gmb) from each section, and the correlation coefficients varied from 0.79 to as high as 0.98. Better correlations were found when the coring operation was completed shortly after the GPR surveying. A combined correlation factor of 0.80 was determined using the data from all four sections. In continuation of the successes from the initial field validation trial, additional field trials are anticipated. These future field trials will further develop an implementation plan, and survey methodology, for the collection of post-construction HMA density measurements.

Language

  • English

Media Info

  • Media Type: DVD
  • Features: Figures; Photos; References; Tables;
  • Pagination: 15p
  • Monograph Title: TRB 89th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

Filing Info

  • Accession Number: 01151220
  • Record Type: Publication
  • Report/Paper Numbers: 10-2266
  • Files: TRIS, TRB
  • Created Date: Jan 25 2010 11:03AM