MEASUREMENT OF THE REFRACTIVE INDEX OF GLASS BEADS USED FOR TRAFFIC MARKINGS

The present Australian standard e42-1967, glass beads for traffic markings, requires the refractive index of the beads to be measured by the Becke line method, which is of the liquid immersion type. Though it is sufficiently accurate for practical purposes, it is time consuming and requires a wide range of liquids of different refractive indices to be available. An alternative, non-immersion method is presented which is much quicker to perform and for typical beads used for pavement markings has an accuracy of + or - 0.001. The method is based on the same principle as the formation of the well known rainbow. This alternative method, if used with a white light source also can be used to give a rapid, accurate determination of the dispersion of the glass. /Author/TRRL/

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 26-31
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00165720
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: Analytic
  • Files: ITRD, TRIS
  • Created Date: May 18 1978 12:00AM