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Mid-America Transportation Center

Performance Measures of Warm Asphalt Mixtures for Safe and Reliable Freight Transportation (Phase 2: Evaluation of Friction and Raveling Characteristics of Warm Mix Asphalt Mixtures with Anti-stripping Agents)

Final Report
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Researchers

  • Principal Investigator: Hosin Lee (hlee@engineering.uiowa.edu 319-335-6818)
  • Co-Principal Investigator: Yongjoo Kim (yongjook@gmail.com 319-335-6800)
  • Graduate Students
  • Nishant Sheth
  • Anand Sampath
  • Anand Sampath
  • Nishant Sheth
  • Undergraduate Students
  • Adam Woods
  • Antonio Motyko
  • Clinton Vanwinkle
  • Adam Woods
  • Antonio Motyko
  • Clinton Vanwinkle
  • Project Status
    Complete
    Sponsors & Partners
  • University of Iowa
  • About this Project
    Brief Project Description & Background
    It is anticipated that more highway pavements be constructed using warm mix asphalt (WMA) mixtures in order to reduce carbon dioxide emission while achieving the longer performance life due to the significantly reduced oxidation of asphalt. During the phase 1 study, six commercially available WMA products were evaluated in the laboratory: Advera WMA, Asphalt-min�, CECABASE RT�, Evotherm J1, Rediset WMX and Sasobit�. Based on the laboratory test results obtained from the phase 1 study, it was found that these WMA mixtures were susceptible to the moisture damage. Therefore, it is critical to consider anti-stripping agents for WMA mixtures. To be used in highways under a heavy traffic with a high tire pressure, their friction and raveling characteristics should be evaluated and compared against both the control WMA mixture and the control HMA mixture.
    Research Objective
    Based on the moisture susceptibility test, no WMA mixtures satisfied the Superpave requirement. Therefore, it is critically needed that the use of anti-stripping agents should be evaluated to improve the moisture susceptibility of WMA mixtures. To address a safety concern for WMA mixtures under the heavy truck traffic with a high tire pressure, the friction and raveling characteristics should be evaluated.
    Potential Benefits
    The main product anticipated from this research is the safe and reliable WMA mixtures with a WMA additive and an anti-stripping agent. Upon completion of the proposed phase 2 study, the most appropriate WMA additive and anti-stripping agent will be identified to produce WMA mixtures with a resistance to moisture damage, skidding and raveling. This information would be very useful for all pavement engineers, who are interested in building the WMA pavement under a heavy traffic with a high tire pressure.
    Abstract
    Warm mix asphalt (WMA) is an emerging technology that can allow asphalt to flow at a lower temperature for mixing, placing and compaction. The advantages of WMA include reduced fuel consumption, less carbon dioxide emission, longer paving season, longer hauling distance, reduced oxidation of asphalt, early opening to traffic and a better working environment. However, to provide a safe and reliable highway for heavier truck traffic with a high tire pressure, WMA mixtures must not only possess an adequate strength but also provide a sufficient friction coefficient for safety. Phase 1 study was performed to evaluate strength, moisture sensitivity, stiffness, and rutting resistance of WMA mixtures with six WMA additives, which include CECABASE RT�, Sasobit�, Asphalt-min�, Advera WMA, Evotherm J1, and RedisetTM WMX, along with the control WMA mixture without any additive and the control HMA mixture. Overall, Sasobit�, Evotherm J1 and RedisetTM WMX were effective in producing WMA mixtures in the laboratory that is comparable to HMA mixtures. However, based on the moisture susceptibility test, no WMA mixtures satisfied the Superpave requirement. Therefore, it is critically needed that the use of anti-stripping agents should be evaluated to improve the moisture susceptibility of WMA mixtures. To address a safety concern for WMA mixtures under the heavy truck traffic with a high tire pressure, the friction and raveling characteristics should be evaluated.
    Project Amount
    $ 50,000
    Modal Orientation
  • Freight
  • Highways
  • Pavements
  • Safety and Human Performance
  • Structures
  • Technology Transfer Activities
    It is anticipated that more highway pavements be constructed using warm mix asphalt (WMA) mixtures in order to reduce carbon dioxide emission while achieving the longer performance life due to the significantly reduced oxidation of asphalt. During the phase 1 study, six commercially available WMA products were evaluated in the laboratory: Advera WMA, Asphalt-min�, CECABASE RT�, Evotherm J1, Rediset WMX and Sasobit�. Based on the laboratory test results obtained from the phase 1 study, it was found that these WMA mixtures were susceptible to the moisture damage. Therefore, it is critical to consider anti-stripping agents for WMA mixtures. To be used in highways under a heavy traffic with a high tire pressure, their friction and raveling characteristics should be evaluated and compared against both the control WMA mixture and the control HMA mixture.