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ASTM Updates Standards for Pavement Markings

Monday, August 16, 2010

ASTM International has developed one new standard and revised a second one regarding testing and practices involving pavement marking paints.

Using a Chamber to Test Drying Rate

D7539 - Standard Practice for Using a Test Chamber for Humidity Conditioning of Test Panels of Pavement Marking Paints is a new standard that describes the use of a test chamber to test the drying rate of waterborne pavement marking (traffic) paints.

As ASTM notes, the drying rate of organic coatings varies with changes in temperature, air flow, and relative humidity. In particular, the drying rate of waterborne paints depends on the evaporation of water and thus is much more dependent on relative humidity than are solvent-based paints or paints that are 100% solids.

Measurement of the rate of drying of waterborne paints under ambient conditions in laboratories cannot be adequately replicated without some control of the drying conditions. This standard describes a test chamber that provides a means of controlling relative humidity above ambient humidity and minimizing the effects of air flow variability at ambient room temperatures.

If desired, the test chamber can be placed without water in it and with vents wide open in a temperature- and humidity-controlled room to test dry speed at various temperatures, as well as humidity while using the chamber to minimize the effect of air flow.

This practice is particularly useful for testing the drying rate of waterborne pavement marking (traffic) paints where fast dry at elevated ambient humidity is an important feature, ASTM says. For waterborne traffic paints, the test chamber can be used to evaluate dry to no-pick-up (Test Method D711) and water wash-off resistance (Practices D7377 and D7538) at elevated ambient humidity.

Evaluating Traffic Paint Wear

D913 - Standard Practice for Evaluating Degree of Traffic Paint Line Wear has been revised (with title change) to D913-10. This practice is designed to evaluate the resistance of a traffic paint to wear. The performance of paint applied to a bare road surface may not guarantee similar results when the same paint is applied over old paint lines.
 
This practice covers the evaluation of degree of resistance to wear that may occur with traffic paints (traffic markings) in road tests (see Practice D713) or in actual service, using photographic standards for comparative evaluation.