ASTM_D_7681_-_11_2021.pdf

Designation:D768111(Reapproved 2021)Standard Test Method forMeasuring Gradation of Glass Spheres Using a FlowingStream Digital Image Analyzer1This standard is issued under the fixed designation D7681;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the grada-tion(size distribution)of glass spheres used in pavementmarking systems using a Flowing Stream Digital Analyzer.Typical gradations for pavement marking systems are definedin ranges from Type 0 through 5 in AASHTO M247-08.1.2 This test method provides for the presentation of the sizedata in a variety of formats to the requirements of the agencypavement marking material specification.For most specifica-tions the standard format is to present the size data as“PercentRetained”or“Percent Passing”relative to a series of standardUS sieve sizes.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2B215 Practices for Sampling Metal PowdersE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 AASHTO Standards:3AASHTO M247-08 Standard Glass Beads Used in TrafficMarkings3.Terminology3.1 Definitions:3.1.1 flowing stream digital image analyzer,na computercontrolled particle size analyzer employing a high resolutiondigital imaging device and computer image processing soft-ware to do photo optical single particle counting and particlesize analysis.3.1.2 gradation of glass beads,nthe measurement of thesize(diameter)of glass beads and their subsequent presentationin ranges between ASTM standard sieve sizes and/or microndesignation starting with the largest to the smallest;the rangesare listed as“percent passing”and“percent retained.”4.Summary of Test Method4.1 The glass particles are run through a flowing streamdigital image analyzer,a measuring system for determining thegradation(size distribution)of dry,free flowing and harmlessbulk products.The total recommended measuring range isbetween 100 m and 2.36 mm.The operating test method usesphoto optical single particle counting technology for the imageprocessing.The measurement time depends on the quantity ofmaterial to be measured,the width of the metering feeder andthe mean grain size.The quantity of material to be measureddepends on the grain size and the width of the metering feeder.Typical measuring times are approximately 2 to 10 min.5.Significance and Use5.1 The gradation(size distribution)of glass beads has asignificant influence on the retroreflective efficiency of apavement marking system.5.2 This test method is for the characterization of thegradation(size distribution)of glass beads for the purpose of1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.44 on Traffic Coatings.Current edition approved Nov.1,2021.Published November 2021.Originallyapproved in 2011.Last previous edition approved in 2016 as D7681 11(2016)1.DOI:10.1520/D7681-11R21.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from American Association of State Highway and TransportationOfficials(AASHTO),444 N.Capitol St.,NW,Suite 249,Washington,DC 20001,http:/www.transportation.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1?compliance testing against standard specification for glassbeads in pavement marking applications.5.3 While there are