Ground Penetrating Radar (GPR) Analysis: Phase I

The objective of this work is to evaluate the feasibility of expanding the Montana Department of Transportation's (MDT's) Ground Penetrating Radar (GPR) program to a broader range of pavement evaluation activities. Currently, MDT uses GPR in conjunction with its Falling Weight Deflectometer (FWD) data collection program to provide layer thickness data for backcalculation. This program has included a review of literature and software dealing with pavement applications of GPR, a survey of state highway agency (SHA) use of GPR for pavement applications, a review of MDT's GPR program, and a review of MDT's pavement structures, environment, and pavement management, and rehabilitation practices. A detailed review of 47 documented studies shows that GPR pavement thickness measurements typically fall within 2-10% of core values for the bound layers. Most of these studies have used a 1.0 GHz horn antenna (vs. the 2.0 GHz antenna currently used by MDT). Accuracy of the unbound material is less precisely documented. The survey of SHA GPR practice supports the application of GPR for pavement thickness measurements—some agencies use GPR on a regular basis, while others use GPR on a project-specific basis. The application of GPR for measuring density of new AC pavement is currently being developed by Texas and Florida DOTs. Montana's pavement network is 97% AC, with mostly aggregate base but some areas with cement-treated base, and maintenance is typically carried out using chip seals. Based on an evaluation of MDT's rehabilitation and reconstruction practices, it appears that the GPR program can be expanded to provide useful information for the following applications: (a) calculation of structural number for pavement reconstruction and rehabilitation design; (b) insuring proper depth control for mill and fill rehabilitation, and cold in-place recycling; (c) improved structural capacity calculation for network level evaluation; and (d) quality assurance of new pavement thickness and density. In order to investigate the feasibility and value of these program expansions, it is recommended that a field evaluation project be designed and implemented to evaluate the accuracy of GPR pavement thickness (and density) data on Montana pavements, and to correlate these findings with the accuracy requirements of the individual applications.

Language

  • English

Media Info

  • Media Type: Web
  • Edition: Phase I Report
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 105p

Subject/Index Terms

Filing Info

  • Accession Number: 01155049
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/MT-09-005/8201, MT308813, C08-005
  • Contract Numbers: HWY-308813; RP Project # - 8201
  • Files: NTL, TRIS, USDOT, STATEDOT
  • Created Date: Apr 21 2010 3:46PM