Research on Tack Coats in Thin Asphalt Overlay Pavements

A tack coat is a thin bituminous liquid asphalt, emulsion or cutback layer applied between asphalt pavement lifts to promote bonding. Adequate bonding between lifts and especially between the existing road surface and an overlay is critical in order for the completed pavement structure to behave as a single unit and provide adequate strength. Inadequate bonding between layers can result in delamination (debonding) followed by slippage cracking, longitudinal wheel path cracking, fatigue cracking, and other distresses such as potholes that greatly reduce pavement life. The effect of tack coats is considered even more significant when a thin lift is overlaid on an existing old (and aged) pavement surface. Due to numerous advantages and benefits, thin asphalt overlays are increasingly adopted in Nebraska as a promising pavement preservation approach and the thin overlay practice is expected to grow for future projects. Based on the significance and expected trend, it is necessary to evaluate the current tack coat practice for the thin lift overlay in Nebraska and to seek potential improvements of the current practice for future applications. To meet the research need, this project proposes an in-depth literature review to survey published studies on tack coat applications in particular for the thin asphalt overlays. This extensive literature review will include regional (e.g., state departments of transportation research reports), national, and international studies. Literature review results will then be compared to Nebraska's current tack coating practices (such as type of tack coats, application rates, construction practices, etc.) to seek any improved applications that can be further evaluated through experimental tests.


    • English


    • Status: Active
    • Contract Numbers:

      SPR-P1(15) M039

    • Sponsor Organizations:

      Federal Highway Administration

      1200 New Jersey Avenue, SE
      Washington, DC  United States  20590

      Nebraska Department of Roads

      P.O. Box 94759
      Highway Building
      Lincoln, NE  United States  68509-4759
    • Performing Organizations:

      University of Nebraska, Lincoln

      527 Nebraska Hall
      Lincoln, NE  United States  68588-0529
    • Principal Investigators:

      Kim, Yong-Rak

    • Start Date: 20150301
    • Expected Completion Date: 0
    • Actual Completion Date: 20170430
    • Source Data: RiP Project 39434

    Subject/Index Terms

    Filing Info

    • Accession Number: 01560271
    • Record Type: Research project
    • Source Agency: Nebraska Department of Roads
    • Contract Numbers: SPR-P1(15) M039
    • Files: RiP, STATEDOT
    • Created Date: Apr 11 2015 1:00AM