Recommended Laboratory Test for Predicting the Initial Retroreflectivity of Pavement Markings from Glass Bead Quality

The initial retro-reflectivity level of pavement markings is greatly dependent on the quality of glass beads applied on top of the marking material. Agency experience has shown that glass beads meeting the same specifications for gradation and roundness and applied by the same paint crew with identical equipment can exhibit a difference of 200 mcd/lx/sq m from one batch of glass beads to another. In Iowa, an increase of 100 to 200 mcd/lux/sq m in initial retro-reflectivity levels can lead to an additional year of useful life from a pavement marking. A quick, reproducible, and standardized laboratory test method is needed to predict the initial level of retro-reflectivity a particular batch of glass beads can provide. Such a test can be used by purchasing agencies to screen glass beads before they are applied to the road. The objective of this project is to develop a laboratory test to predict the initial retro-reflectivity of glass beads applied on top of liquid pavement markings. Actual field applications will need to be compared to laboratory tests to determine a method for accurately predicting how various batches of glass beads will perform in providing initial retro-reflectivity. The test should be rapid (less than 24 hours) and able to be conducted in a typical state DOT materials testing laboratory.</font></div>


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  • Status: Completed
  • Funding: $349990.00
  • Contract Numbers:

    Project 4-38

  • 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:

    Iowa State University, Ames

    Ames, IA  United States  50011
  • Principal Investigators:

    Smadi, Omar

  • Start Date: 20090625
  • Expected Completion Date: 0
  • Actual Completion Date: 20121130
  • Source Data: RiP Project 17901

Subject/Index Terms

Filing Info

  • Accession Number: 01464486
  • Record Type: Research project
  • Source Agency: National Cooperative Highway Research Program
  • Contract Numbers: Project 4-38
  • Files: TRB, RiP, USDOT
  • Created Date: Jan 3 2013 2:43PM