1、Designation:D768111Standard 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,th
2、e 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 pavementma
3、rking 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 mark
4、ing 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 thiss
5、tandard.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenc
6、ed 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
7、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 analysi
8、s.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
9、 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 us
10、esphoto 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 fe
11、eder.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 distribut
12、ion)of glass beads for the purpose ofcompliance testing against standard specification for glassbeads in pavement marking applications.5.3 While there are potential industrial applications for thistest method beyond the measurement of gradation(size distri-bution)of glass beads for pavement markings
13、,those arebeyond the scope of this standard.6.Apparatus6.1 Typical Instrument Operating Conditions(Fig.1):6.1.1 Environmental temperature 10C.40C.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility
14、 ofSubcommittee D01.44 on Traffic Coatings.Current edition approved Jan.1,2011.Published February 2011.DOI:10.1520/D7681112For 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
15、 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 Consho
16、hocken,PA 19428-2959.United States1 6.1.2 Air Humidity 80%maximum relative humidity attemperatures up to 30C,linear decrease to 50%maximumrelative humidity at a temperature of 40C.6.1.3 Height of installation and operation maximum 300m above sea level.6.1.4 Installation location place the particle analyzer ona firm,horizontal,vibration free surface.6.1.5 Light conditions avoid strong direct external lighton the particle measurement shaft or on the cameras.6.1.6 This test method is designed for i
