Pavement Markings Materials
Posted by Jesse Willoughby on Fri, May 29, 2009 @ 06:25 AM
Many materials can be used for pavement marking. The choice depends on cost, durability, retroreflectivity, pavement surface, and drying time.
Paint Water-based paint, applied either cold or hot, is the most commonly used pavement marking. It is low cost with a short drying time, but its visibility on wet nights is just moderate. Traffic and snow plowing wear it away in about a year. Oil-based (alkyd) paint, when used, must meet environmental air quality restrictions
on volatile organic compound (VOC) emissions.
Thermoplastics These pavement-marking materials are made of thermoplastic heated to about 400° F and spread onto the pavement surface. Glass beads to increase reflections can be spread on top, mixed in, or both. Thermoplastics have a long service life, good visibility, and good retroreflectivity. The no-track time is short, and cost is mid-range. Special application equipment is required.
Epoxy Also applied as a liquid with special equipment, epoxy has good visibility and retroreflectivity, and cost is moderate. No-track time is 5-20 minutes. Markings last 3 to 4 years.
Tapes Pre-formed tape can be either inlaid as part of new construction, or overlaid. It has excellent visibility and retroreflectivity and lasts 7-8 years, but is higher cost. Wet reflective tape has excellent wet night retroreflectivity with about a 4-year life. Cost is medium and durability is poor. Modifications are being made to produce a tape with both durability and wet night
retroreflective quality.
Markings that must be visible at night shall be retroreflective. In general this applies to all pavement markings except parking lines and curb markings. For paint, glass beads are mixed in or dropped on the markings while still wet. Durable products are made with reflecting materials. In pedestrian areas, marking materials should not create slipping or tripping hazards.
Raised pavement markers can be useful to supplement pavement marking, but cost is a factor, and they must be correctly installed. Wet reflective tape is another supplement option.