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ASTM D7971-20

Current Revision

Standard Guide for Measuring Roundness of Glass Spheres Using a Flowing Stream Digital Image Analyzer

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1.1 This guide covers the determination of the roundness of glass spheres used in pavement marking systems using a flowing stream digital analyzer. Typical gradations for pavement marking systems are defined in ranges from Type 0 through 5 in AASHTO M247.

1.2 This guide provides for the presentation of roundness data in a variety of formats to the requirement of the agency pavement marking material specification. For most specifications the standard format is to present the roundness data as Percent True Spheres relative to a series of standard ASTM sieve sizes.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

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

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.


4.1 The roundness of glass beads has a significant influence on the retroreflective efficiency of a pavement marking system.

4.2 The guide is for the characterization of the roundness of glass beads for the purpose of compliance testing against standard specification for glass beads in pavement marking applications.

4.3 While there are potential industrial applications for this guide beyond the measurement of roundness of glass beads for pavement markings, those are beyond the scope of this standard.

SDO ASTM: ASTM International
Document Number D7971
Publication Date June 1, 2020
Language en - English
Page Count 4
Revision Level 20
Supercedes
Committee D01.44
Publish Date Document Id Type View
June 1, 2020 D7971-20 Revision
April 1, 2015 D7971-15 Revision