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Mid-America Transportation Center

NDOR Use of Ground Penetrating Radar for Construction Quality Assurance of Concrete Pavement

Final Report
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Researchers

  • Principal Investigator: George Morcous (gmorcous2@unl.edu 402-554-0571)
  • Co-Principal Investigator: Ece Erdogmus (eerdogmus2@unl.edu
  • Project Status
    Complete
    Sponsors & Partners
  • Nebraska Department of Roads
  • About this Project
    Brief Project Description & Background
    Ground Penetrating Radar (GPR) is a well-established technique for subsurface exploration. Recently, GPR has been used for several transportation applications, such as measuring layer thickness in asphalt pavement, locating reinforcing bars and tendons, and detecting deteriorations and anomalies in concrete structures. The main advantages of GPR are speed, accuracy, and cost-effectiveness when scans are conducted on large areas. The goal of this project is to investigate the accuracy and cost-effectiveness of using GPR for measuring the thickness of concrete pavement for quality assurance purposes.
    Research Objective
    The objective of this research is to investigate the feasibility of using GPR on a routine basis for measuring the thickness of concrete pavements. It will specifically determine the accuracy of GPR in measuring the thickness of concrete pavement using "verification cores". It will investigate the effect of various parameters on GPR accuracy, such as pavement age, thickness, density and base type and evaluate the repeatability of GPR in thickness measurement in dry and wet conditions
    Potential Benefits
    If successful, this research will provide a cost-effective, non-destructive technique for accurately measuring the thickness of concrete pavement.
    Abstract
    Extracting concrete cores is the most common method for measuring the thickness of concrete pavement for construction quality control. Although this method provides a relatively accurate thickness measurement, it is destructive, labor intensive, and time consuming. Moreover, concrete cores are usually taken approximately every 750 ft, which may be inadequate for estimating the actual thickness profile of a pavement section; however extracting more cores would damage the pavement extensively and increase the labor cost and time excessively. Ground Penetrating Radar (GPR) is a well-established technique for subsurface exploration. Recently, GPR has been used for several transportation applications, such as measuring layer thickness in asphalt pavement, locating reinforcing bars and tendons, and detecting deteriorations and anomalies in concrete structures. The main advantages of GPR are speed, accuracy, and cost-effectiveness when scans are conducted on large areas. The objective of this project is to investigate the accuracy and cost-effectiveness of using GPR for measuring the thickness of concrete pavement for quality assurance purposes. The GPR systems GSSI SIR20 and SIR3000 with a high resolution 1.6 MHz ground coupled antenna were used in measuring the thickness of concrete pavement up to 14 inch thick. Several laboratory and field tests have been carried out to determine the accuracy of the GPR measurement at different concrete ages and when various metal artifacts are used underneath the concrete to improve the reflectivity of the bottom surface. Testing results have indicated that GPR is a cost-effective non-destructive technique for measuring the thickness of concrete pavement, compared to extracting concrete cores, and an accuracy of 1/8 in can be achieved when appropriate reflectors and calibration cores are used.
    Project Amount
    $ 28,667