Browsing by Author "Johnson, Eddie N"

Now showing 1 - 4 of 4
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    Asphalt Pavement Analyzer (APA) Evaluation
    (2002-09-01) Skok, Eugene L; Johnson, Eddie N; Turk, Amir
    This report considers the Asphalt Pavement Analyzer (APA) as a tool for evaluating the rutting susceptibility of Minnesota Hot Mix Asphalt (HMA). Its authors analyze the 25 responses to a questionnaire sent to members of the APA Users' Group and conduct a literature review. Based on this evidence, they recommend that Mn/DOT purchase an APA. The tool provides a measure of rutting susceptibility; is reasonably reliable and repeatable; and has been used by over 60 agencies and contractors. In addition, procedures for conducting tests are available in ASTM and AASHTO formats and the Users' Group provides a forum for discussion and support. Keywords-asphalt pavement analyzer, hot mix asphalt, rutting, ESALs
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    Best Practices for the Design and Construction of Low Volume Roads - REVISED
    (2003-11-01) Skok, Eugene L; Timm, David H; Brown, Marcus; Clyne, Timothy R; Johnson, Eddie N
    This report presents information about the use of the mechanistic-empirical procedure (MnPAVE) in designing hot-mix asphalt pavements in Minnesota. Researchers developed the MnPAVE software program using information from the Minnesota Road Research Project (Mn/ROAD) test facility and from 40-year-old test sections around Minnesota. MnPAVE procedures use Equivalent Standard Axle Loads (ESALs) to evaluate traffic loading, and the report includes methods to estimate these values for design purposes over a 20-year design life, as well as a procedure to measure vehicle type distributions. In addition, the report presents an evaluation of subgrade soils for each thickness design procedure, summarizes Minnesota Department of Transportation specifications that relate to embankment soil construction and to construction of the pavement section materials, and recommends specific density or quality compaction using a control strip. It also includes best practices on setting up projects most effectively to follow specifications.
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    Special Practices for Design and Construction of Subgrades in Poor, Wet, and/or Saturated Soil Conditions
    (2003-05-01) Skok, Eugene L; Johnson, Eddie N; Brown, Marcus
    Highway embankment construction progresses vertically in stages, beginning with the subgrade. For a variety of reasons, it is desirable to use naturally occurring soils for subgrade material. In some cases this is not possible due to poor soil conditions; in order to avoid realignment it is necessary to improve the subgrade material. A literature review provides background for special construction methods to be used for subgrade soil enhancement. Additonal information about modification, stabilization, reinforcement, and substitution methods and material was gathered from a questionnaire directed to Minnesota state, county, and city highway engineers. Based on questionnaire responses, a series of highway agency interviews were conducted to provide more detailed information about the enhancement methods. Enhancement selection recommendations and special practice methods for construction were developed from the agency interviews, questionnaire responses, and literature review.
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    Validation of Superpave Fine Aggregate Angularity Values
    (2004-03-01) Johnson, Eddie N; Marasteanu, Mihai O; Clyne, Timothy R; Li, Xinjun
    This report presents the results of laboratory testing to validate the use of Fine Aggregate Angularity (FAA) measurements with the Superpave method of Hot Mix Asphalt (HMA) design. A search of literature and Minnesota FAA data was conducted in preparation for FAA testing of aggregates and HMA design. Laboratory tests of aggregates included sieve analysis, specific gravity and FAA. Additional work was also performed by acquiring digital imaging data for the aggregates. Testing of asphalt mixtures included dynamic modulus tests and asphalt pavement analyzer tests. Testing was performed on four asphalt mixtures representing a range of Minnesota FAA values. Dynamic modulus testing was performed at three temperatures and five frequencies. Data from the dynamic modulus tests were processed using nonlinear regression. The resulting master curves of dynamic modulus vs. frequency were referenced to test temperature 54C. Asphalt pavement analyzer data at 54C was analyzed with respect to rutting curve. Laboratory test results for aggregates and mixtures were analyzed together using statistical methods to develop correlation coefficients and linear trends. It was found that dynamic modulus and rut resistance values are strongly related to aggregate blend FAA. Some additional parameters from digital imaging also predicted modulus and rut resistance very well and should be included in future reference.