Field Versus Laboratory Volumetrics and Mechanical Properties

In the quality assurance (QA) of hot mix asphalt construction, the results of volumetric testing conducted by the contractor and agency are often compared statistically to verify the contractor's test results. Such comparisons help the agency judge whether its QA test results are from the same population as the contractor's test results. However, because the tests are performed by different operators using different equipment and with potentially different methods, variability of the test results is inevitable. A further source of variability arises when the sampling and compaction of the specimens are not the same, i.e., when results from laboratory-mixed and compacted specimens are compared to those from plant-mixed, laboratory-compacted specimens, or plant-mixed, field-compacted specimens, or both, on a single project. A major barrier to conducting a sound QA program is quantifying the variability that arises when it is necessary to compare the properties of asphalt mixture specimens that may be (1) produced in a laboratory or at the plant, (2) compacted in different physical locations, and (3) compacted in the laboratory or in-place on the pavement. The objectives of this research are to (1) determine causes of variability and the precision and bias for volumetric and mechanical properties of dense-graded asphalt mixtures measured within and among these three specimen types: (a) laboratory mixed and compacted, (b) plant mixed and laboratory compacted, and (c) plant mixed and field compacted; and (2) prepare a recommended practice for state departments of transportation (DOTs) to incorporate these results in specifications and criteria for (a) quality assurance, (b) mix design verification or validation, and (c) structural design and forensic studies. The research will primarily address variability associated with volumetric and mechanical test results within and among the three specimen types defined herein and not the test method's within- and among-laboratory variability (i.e., repeatability and reproducibility or precision statement), which is generally well established and documented. However, the effect of this laboratory testing variability will be considered in accomplishing the project objectives.

Language

  • English

Project

  • Status: Completed
  • Funding: $500000.00
  • Contract Numbers:

    Project 9-48

    10-1B

  • Sponsor Organizations:

    Federal Highway Administration

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

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Project Managers:

    Harrigan, Edward

  • Performing Organizations:

    Louisiana Transportation Research Center

    4101 Gourrier Avenue
    Baton Rouge, LA  United States  70808
  • Principal Investigators:

    Mohammad, Louay

  • Start Date: 20090801
  • Expected Completion Date: 0
  • Actual Completion Date: 20151231
  • Source Data: RiP Project 17991

Subject/Index Terms

Filing Info

  • Accession Number: 01464476
  • Record Type: Research project
  • Source Agency: National Cooperative Highway Research Program
  • Contract Numbers: Project 9-48, 10-1B
  • Files: TRB, RiP, USDOT
  • Created Date: Jan 3 2013 2:43PM