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Mid-America Transportation Center

Strain Distribution and Crack Detection in Concrete Overlays with Pulse Pre-Pump Brillouin Optical Time Domain Analysis

Final Report
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Researchers

  • Principal Investigator: Genda Chen (gchen@mst.edu (573) 341-4462)
  • Project Status
    Complete
    About this Project
    Brief Project Description & Background
    Ultrathin concrete overlays as a potential pavement rehabilitation strategy will be loaded under a standard truck or subjected to cold weather effects at MnROAD - a pavement test track located near ALbertville, MN. Strain, crack width, temperature, and other environmental factors will be measured periodically to understand loading and environmental effects on the behavior and performance of the ultrathin panels and their interaction with substrates over time. Laboratory tests will also be conducted for calibration and optimization of the sensitivity, spatial resolution, and strain transfer effect of optical fiber sensors with various packaging materials (coatings). Major outcomes will include repeatable and precise installation procedures for various sensors in cast-in-place panel applications, packaging sensor performances in field application, verified sensor specification, and performance data of concrete panels.
    Research Objective
    The objectives of this study are to monitor and analyze the field performance of unbonded concrete overlays with limited sensors which will have been installed by July 2013 through a previous study by Missouri University of Science and Technology, North Dakota State University, and the University of Minnesota; and to develop and validate a field-deployable optical monitoring system for structural condition assessment of concrete overlays in pavement applications.
    Potential Benefits
    Ultrathin unbonded concrete panels have recently been introduced to rehabilitate existing highway pavements with surface deterioration. Their use can accelerate the construction of highway pavements, preserving the public demand for highway capacity. However, field performance data on unbonded concrete panels is currently lacking. Therefore, field monitoring of unbonded concrete panels can provide critical data sets that will lead to the improved safety of traffic, reduced fuel consumption (thus CO2 emission), and enhanced service level of highways. In addition, laboratory tests of concrete panels can shed light on the potential failure modes of unbonded concrete panels in various construction conditions, including the effects of plastic fibers (length and volume), concrete strength, and the thickness of separator between the panels and their existing substrate.
    Abstract
    An instrumentation system including electric and optic sensors will have been installed by July 1, 2013 in 6 ft × 6 ft, 3-in thick unbonded concrete panels and their existing substrates over an approximately 500 ft long distance in cell-40 at MnROAD - a pavement test track located near Albertville, MN. The unbonded concrete pavement/overlay panels will be loaded under a standard design truck or subjected to cold weather effects over the years. Their field performance will provide the required data for a widespread implementation of this potentially viable solution for aging highway pavement rehabilitation. Strain, crack width, temperature, and other environmental factors will be measured periodically to understand loading and environmental effects on the behavior and performance of the ultrathin panels and their interaction with substrates over time. Laboratory tests will also be conducted for calibration and optimization of the sensitivity, spatial resolution, and strain transfer effect of optical fiber sensors with various packaging materials (coatings). Major outcomes will include repeatable and precise installation procedures for various sensors in cast-in-place panel applications, packaging sensor performances in field application, verified sensor specification, and performance data of concrete panels. This project represents a collaborative effort among Missouri University of Science and Technology (Missouri S&T), North Dakota State University (NDSU), and the University of Minnesota (UMN), taking advantage of their experiences in continuous optical fiber sensing, discrete optical fiber sensing, and pavement engineering.
    Project Amount
    $ $100,000