This research effort which reviewed and analyzed worldwide research and practices, attempted to identify those variables that influence the effective utilization of glass beads on pavement markings and evaluate those variables by laboratory and field tests. The effort was also designed to: determine the capability and economics of producing glass beads of specified gradation, composition, shape, etc.; develop practical specifications and criteria for the selection and use of beads for reflectorizing traffic paint markings; and evaluate the probable benefits that would accrue should the proposed specifications be adopted. Major examples of the various uses and practices are listed. The performance of retroreflecting glass sheres in pavement markings is found to be strongly influenced by the binder (paint) in which the beads are embedded. A general pattern of contract between performance on portland cement concrete pavement and bituminous concrete pavement was noted: higher brightness on concrete, but more rapid wear; less bright but longer lasting on bituminous pavement. No useful wet reflection test lines appeared after exposure to traffic wear. Improved bead application procedures in Pennsylvania are discussed, as well as the cost of beads. Recommendations are presented relating to: binder thickness, gradation, bead-to-binder ratio, surface treatment, and refractive index.

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Filing Info

  • Accession Number: 00149196
  • Record Type: Publication
  • Report/Paper Numbers: Project 5-5A
  • Files: TRIS, TRB
  • Created Date: Mar 30 1977 12:00AM