Chip Seal Construction Variability and Its Impact on Performance

Major changes have been made to the way pavement preservation activities would be performed by the North Carolina Department of Transportation (NCDOT) due to recent mandates by the North Carolina State Legislature. The new requirement is that 4,300 lane miles are to be paved using pavement preservation treatments. Chip seals would constitute a large part of the $65 million pavement preservation program to meet this goal. The major change that will affect chip seal construction is the new directive that describes gradual increases in chip seal outsourcing from 30% in 2015-2016 fiscal year to 80% by 2017-2018 fiscal year. The increased amount of outsourced chip seal construction will change the focus for NCDOT engineers from good construction practices to the development of specifications and quality control (QC)/quality assurance (QA) programs. Fortunately, a series of research projects has been funded by the NCDOT for North Carolina State University to investigate various ways to improve chip seal performance. The findings and the experience gained from these research projects will be a great asset to the NCDOT in its ability to meet these new challenges and requirements. The objectives of the proposed research effort are to: (1) develop a comprehensive synthesis of best practices for chip seal treatments, (2) conduct a one-day workshop to share information gained from previous chip seal projects funded by the NCDOT, (3) determine the range of parameter variability and the impact of such variability on the performance of chip seals, (4) develop acceptable tolerance ranges for critical chip seal design and construction parameters to be used in new chip seal specifications based on performance, and (5) develop guidelines for a chip seal Certification and QC/QA program. The proposed research will incorporate both field construction and sampling efforts as well as a laboratory experimental test plan to identify and quantify the variability associated with chip seal construction and to determine tolerance ranges that define acceptable deviation from target rates and material parameters. The number of field sites to be used in this study will be determined after consultation with the Project Steering Committee at the onset of the research project. For the purpose of this proposal, it is assumed that five chip seal projects will be selected for the field trials: three projects that use granite 78M aggregate and two projects that use lightweight aggregate. This research will result in a manual for chip seal best practices, a one-day workshop, allowable tolerances for design and construction variables in the NCDOT’s new chip seal specifications, and recommendations for a chip seal Certification and QC/QA program. These outcomes will not only ensure that the NCDOT adheres to the mandates defined by the legislature, but also will ensure quality construction of the most important pavement preservation treatments in North Carolina, i.e., chip seals.


  • English


  • Status: Active
  • Contract Numbers:

    RP 2015-19

  • Sponsor Organizations:

    North Carolina Department of Transportation

    Research and Development
    1549 Mail Service Center
    Raleigh, NC  United States  27699-1549
  • Project Managers:

    Kadibhai, Mustansir

  • Performing Organizations:

    North Carolina State University, Raleigh

    Department of Civil Engineering, Campus Box 7908
    Raleigh, NC  United States  27695-7908
  • Principal Investigators:

    Kim, Y

  • Start Date: 20140816
  • Expected Completion Date: 20160815
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01582668
  • Record Type: Research project
  • Source Agency: North Carolina Department of Transportation
  • Contract Numbers: RP 2015-19
  • Files: RiP, STATEDOT
  • Created Date: Dec 2 2015 2:27PM