EFFECT OF GLASS BEADS SIZE ON THEIR WET WEATHER RETROREFLECTIVITY

When a road surface is wet, the retroreflectivity of standard glass beadson linemarking is negligible. In recent years it has been demonstrated that large beads, even when the road surface is wet, retain significant retroreflectivity and thus remain visible to drivers. Unfortunately, the larger the beads the more expensive per unit mass they are. How large shouldthe beads be to economically obtain satisfactory wet weather performance? To answer this question it is necessary to quantify the relationship between the wet weather retroreflectivity of glass beads and their size. This is the aim of the present investigation. The relationship between the glass beads' diameter and wet weather retroreflectivity was measured on a road using a laser retroreflectometer. This was supplemented by laboratorywork which looked at the micro-texture of a beaded paint layer. It was found that the larger the beads the better they perform in the wet. To achieve a good wet weather performance, glass beads of about 1 mm in diameteror larger should be used. However, the wet weather retroreflectivity of a beaded paint surface depends not only on the beads' properties but also on how quickly the water drains off, and therefore also on the micro-texture of the surface. (a) For the covering abstract of this conference see IRRD abstract no. 861222.

• Record URL:
  http://arrbknowledge.com
• Corporate Authors:

  ARRB

  Melbourne, Victoria  Australia 
• Authors:
  • MEYDAN, A
• Conference:
  • 17TH ARRB CONFERENCE, GOLD COAST, QUEENSLAND, 15-19 AUGUST 1994; PROCEEDINGS; VOLUME 17, PART 5
• Publication Date: 1994

Language

• English

Media Info

• Features: References;
• Pagination: p. 201-14

Subject/Index Terms

• TRT Terms: Conferences; Glass beads; Mileposts; Pavements; Reflectivity; Road markings; Size; Surface course (Pavements); Visibility; Wet weather
• Uncontrolled Terms: Wet pavements
• ITRD Terms: 562: Carriageway marking; 8525: Conference; 9014: Dimension; 4548: Glass shot; 594: Marker post; 4555: Material (constr); 5925: Properties; 5926: Reflectivity; 6255: Test; 6783: Visibility; 3015: Wet road
• Subject Areas: Highways; Pavements;

Filing Info

• Accession Number: 00669803
• Record Type: Publication
• Source Agency: ARRB
• Files: ITRD, ATRI
• Created Date: Dec 23 1994 12:00AM