Scope:

ASTM D7681 test technique determines the gradation (size distribution) of glass beads used in pavement marking applications. Glass beads significantly influence the retroreflective effectiveness of a pavement marking system.

Procedure:

In ASTM D7681, a flowing stream digital image analyzer examines the glass particles for image processing and photo-optical single particle counting technology. The amount of material to be measured is determined by the grain size and the metering feeder’s breadth. Typical measurement periods range from 2 to 10 minutes.

Video 01: Overview of a stream image analysis software

Specimen size:

A minimum of 50 ± 5 g of glass beads specimens are examined for gradation (size), as per ASTM D7681.

Data:

In ASTM D7681, the measured result is accessible a few seconds after the measurement is finished and may be presented in a variety of ways and printed and stored using a computer.

Conclusion:

ASTM D7681 test technique determines the gradation (size distribution) of glass beads used in pavement marking applications.