Citation

O'Brien J. Transp. Res. Rec. 1989; 1230: 37-44.

Copyright

(Copyright © 1989, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Embedment characteristics of drop-on moistureproofed and uncoated glass spheres and their subsequent retroreflectivity were evaluated subjectively in various types of hot-applied thermoplastic traffic markings by illuminating test panels in a dark room. In all of the hot-applied thermoplastic traffic marking types tested, uncoated drop-on spheres were generally overembedded because of positive wetting of the spheres by the thermoplastic traffic marking, and their retroreflectivity varied. The use of moistureproofed drop-on spheres in various thermoplastic traffic marking types resulted in optimal bead embedment with subsequent excellent retroreflectivity. The optimal rate of glass sphere application in all of the thermoplastic marking types was found to be 10 lb of moistureproofed glass spheres per 100 sq ft -- this rate enhanced retroreflectivity, bead embedment, and coverage. The retroreflectivity of the standard gradation of glass spheres may be enhanced in all of the thermoplastic types by increasing the percentage of spheres retained on U.S. sieves 30, 40, and 50 and by increasing the overall rounds from 70 to 80 percent.

Record URL:
http://onlinepubs.trb.org/Onlinepubs/trr/1989/1230/1230-005.pdf

Language: en

Keywords

Traffic Signs, Signals and Markings; Glass - Bonding; Light - Reflection; Pavements - Materials; Thermoplastics