ASTM D7971 Standard guidance for Measuring the roundness of glass Spheres using a Flow Digital Image Analyzer includes determining the roundness of glass spheres used in pavement marking systems using a flow digital Image analyzer.
Meaning and use

4.1 The roundness of the glass beads has a significant effect on the reverse reflection efficiency of the pavement marking system.

4.2 This guide is used to characterize the roundness of glass beads for conformance testing to standard specifications for glass beads in pavement marking applications.

4.3 While the potential industrial applications of this guidance extend beyond measuring the roundness of glass beads for pavement markings, these applications are beyond the scope of this standard.

ASTM D7971-2015 Standard Guide for Measuring the Roundness of Glass Spheres Using a Flow Digital Image Analyzer

Step 1: Scope

1.1 This guide covers the use of a flow flow digital analyzer to determine the roundness of glass spheres used in pavement marking systems. Typical grades for pavement marking systems are defined in the type 0 to 5 range in AASHTO M247.

1.2 This Guide specifies the representation of roundness data in various formats to meet the requirements of the Agency pavement marking Material specification. For most specifications, the standard format is to display the roundness data as a percentage true sphere relative to a range of standard ASTM sizing sizes.

1.3 Values expressed in SI units shall be regarded as standard values. No other units of measurement are included in this standard.

1.4 This standard is not intended to address all safety concerns, if any, associated with its use. It is the responsibility of users of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory restrictions prior to use.