Minnesota Department of Transportation

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Research & Innovation

Need statements

NS731: Evaluating and Implementing Ground Penetrating Radar (GPR) for Continuous and Rapid Monitoring of Moisture Fluctuations in In-Service Roads

Problem

Environmental factors such as heavy rainfall, freeze-thaw cycles, and changes in the groundwater table significantly affect moisture levels in pavement foundations, impacting pavement performance over both short and long terms. Accurately monitoring and assessing foundation moisture, especially after extreme events like floods and freeze-thaw cycles, is crucial for pavement engineers to effectively manage traffic by adjusting flow or restrictions based on subsurface moisture conditions. Traditional methods for measuring pavement moisture, including in-place sensors and indirect assessments like FWD, are costly, invasive, slow, offer limited spatial coverage, and disrupt traffic. In contrast, ground penetrating radar (GPR) offers a non-invasive, portable solution for swiftly evaluating extensive road segments, detecting subsurface moisture levels with reasonable cost, thereby supporting local road authorities in promptly assessing moisture conditions in critical pavement areas.

Objective

The aim of this idea or call for research study is to advance the validation and implementation of GPR-based pavement moisture assessments on actual low-volume roads. This involves evaluating GPR's capability to efficiently survey large pavement areas, its effectiveness in monitoring moisture, and its ability to identify sections potentially suffering from drainage inefficiencies. The study would include collaboration between universities, contractors and local road agencies to develop a practical testing and analysis approach, building on the groundwork laid by OMRR researchers and others.

Previous research

Researchers from the OMRR have leveraged sensor and GPR data collected at frequent intervals from various MNROAD test cells to develop analysis approaches for measuring moisture fluctuations in the unbound aggregate layers of in-service pavements using 350-400 MHz GPR equipment. This method, documented in the attached published papers, has shown promising results.

Expected outcomes

  • New or improved technical standard, plan, or specification
  • New or improved manual, handbook, guidelines, or training
  • New or improved tool or equipment
  • New or improved decision support tool, simulation, or model/algorithm (software)

Expected benefits

The numbers 1 and 2 indicate whether the source of the benefit measurement is from: 

  1. A specific research task in your project that supports measuring this particular benefit, or
  2. Implementation of the research findings (anticipating positive results)
  • Decrease Lifecycle Costs: (2)
    • GPR data on seasonal moisture and pavement performance from this study may inform decision-making for pavement loading which could prevent damage and costs if the tool is deployed.
  • Increase Lifecycle: (2)
    • GPR data on seasonal moisture and pavement performance from this study may inform decision-making for pavement loading which could prevent maintenance if the tool is deployed
  • Operation and Maintenance Saving: (2)
    • GPR data on seasonal moisture and pavement performance from this study may inform decision-making for pavement loading which could prevent maintenance if the tool is deployed
  • Safety: (2)
    • GPR data on seasonal moisture and pavement performance from this study may inform decision-making which could include closure or safety measures if the tool is deployed
  • Risk Management: (2)
    • GPR data on seasonal moisture on pavement performance from this study may inform decision-making which could include closure or safety measures if the tool is deployed.

Technical advisory panel

  • TBD