Browsing by Subject "Deicing"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Adaptive Management to Improve De-Icing Operations
    (Minnesota Department of Transportation, 2021-03) Baker, Lawrence A.; Wilson, Bruce; Klimbal, Doug; Furuta, Dan; Friese, Melissa; Bierman, Jacob
    Road de-icing is a major cause of chloride impairment in Minnesota's urban waters. The goal of our study was to develop an adaptive management (AM) strategy to reduce chloride impacts caused by de-icing operations. The AM process was informed by our analysis of chloride movement in a residential watershed, providing feedback to the street department of our collaborator, the City of Edina. A key finding was that most the chloride movement occurred during a small number of events, with half of annual chloride movement occurring in less than 50 hours during each of the two years of study. This observation means that targeting these events might be a more effective way to reduce chloride impacts than more generalized approaches. We also found that a significant amount of chloride added to streets during de-icing accumulated in roadside snow piles, likely contributing to groundwater contamination. To address this concern, we developed a spreadsheet tool to estimate steady-state (long-term) chloride concentrations in groundwater. Scenario analyses indicated that groundwater chloride levels in highly urbanized watersheds would eventually exceed water quality standards. We developed a second model, intended for use by urban planners, to estimate the impact of changing the percentage of salted impervious surface on chloride movement in re-developed watersheds.
  • Thumbnail Image
    Item
    Minnesota Taconite as a Microwave- Absorbing Road Aggregate Material for Deicing and Pothole Patching Applications
    (University of Minnesota Duluth, 2004) Zanko, Lawrence M; Hopstock, David M
  • Thumbnail Image
    Item
    Review of the Applications of Microwave Heating for Asphalt Pavement Maintenance
    (2021-06) Calhoon, Thomas
    The propagation of microcracks into more serious pavement distresses is a major concern for asphalt pavements. Much work has been done to accelerate and control the asphalt self-healing of microcracks through the application of external heating methods including microwave heating. This thesis provides a state of the art of application of microwave heating of asphalt pavements, including self-healing. The principles of microwave heating, components of a microwave system, and different types of microwave systems are discussed. Then, an extensive literature review on the use of microwaves on asphalt pavements is presented. The review covers several applications of microwave heating on asphalt pavements and additives that enhance the microwave-absorbing capabilities of asphalt materials. Then, the results of a laboratory fatigue-heal cycle experiment are presented. The results demonstrate the ability of microwave heating to activate asphalt self-healing. Then, a 1D microwave heat transfer model is presented. A sensitivity analysis is performed on several model parameters. The analysis reveals that some parameters, such as thermal conductivity, do not significantly impact the microwave heating outcome, while some, such as applied microwave power density, do. Finally, recommendations are made for future work including field trials of discussed applications and implementation of the presented model in a computer application.