Follow-On Friction Testing of Retro-Reflective Glass Beads

IN 1993 and 1994 the FA Technical Center conducted an evaluation of retro-reflective beads in airport pavement markings. That study proved that the addition of glass beads greatly enhanced the conspicuity of the surface markings. In the study the beaded stripes had silica (sand) friction enhancement added to the paint. A concern arose as to the friction characteristics of beaded paint without silica.

The current study was conducted to test the friction levels of painted surface markings with and without beads and/or silica. Results of this study indicate that the friction levels of surface painted markings can be increased by adding retro-reflective glass beads to the paint. Silica also increased the friction of the surface markings; however, when glass beads were also added, the benefit of silica was reduced due to its smaller size in relation to the size of the beads.