1、Designation: D7681 11 (Reapproved 2016)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 t
2、he 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 gl
3、ass 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 requireme
4、nts 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
5、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 and health practices and determine the applica-bility of regulat
6、ory limitations prior to use.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 Standar
7、ds: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
8、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 “
9、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 i
10、sbetween 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 measure
11、ddepends 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 met
12、hod 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.
13、Current edition approved April 1, 2016. Published April 2016. Originallyapproved in 2011. Last previous edition approved in 2011 as D7681 11. DOI:10.1520/D768111R16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Bo
14、ok 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 Inte
15、rnational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1compliance 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 gradati
16、on (size distri-bution) of glass beads for pavement markings, those arebeyond the scope of this standard.6. Apparatus6.1 Typical Instrument Operating Conditions (Fig. 1):6.1.1 Environmental temperature 10C.40C.6.1.2 Air Humidity 80 % maximum relative humidity attemperatures up to 30C, linear decreas
17、e 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 part
18、icle measurement shaft or on the cameras.6.1.6 This test method is designed for indoor or outdoor useas prescribed by the manufacturers design and instructions.7. Hazards7.1 General Safety Information:7.1.1 Operate the instrument in accordance with the manu-facturers recommendations following all re
19、quired safety pre-cautions.8. Sampling, Test Specimens, and Test Units8.1 Obtain a minimum of approximately 50 6 5 g specimenof the glass beads to be tested for gradation (size distribution).For larger sizes of glass spheres, such as Type III and larger,whose gradation is defined in AASHTO M247-08,
20、75 to 125 gsamples shall be used.8.2 In order to obtain representative samples when sam-pling from packaged containers, blenders or storage tanks,methods outlined in Practices B215 shall be followed.9. Preparation of Apparatus9.1 Follow the manufacturers instructions for the particleanalyzer being u
21、sed.10. Calibration and Standardization10.1 The particle analyzer, in most cases, will be calibratedby the manufacturer prior to shipping. Re-calibration mightbecome necessary occasionally, for example, after the trans-portation of the instrument or if required by quality manage-ment regulations. In
22、 this case, follow the calibration proceduresas outlined in the manufacturers instruction manual.11. Conditioning11.1 Sample Preparation:11.1.1 Use a sample splitter, if necessary, to reduce theamount of sample to the appropriate size.11.1.2 Pour entire glass bead sample into the glass beaker orsuit
23、able container.11.1.3 Assure glass beads are moisture free and free flow-ing.NOTE 1Check with instrument manufacturer for suggestions on howto best set up any software that comes with their instrument. Setting up theinstrument software properly will speed up any glass sphere gradationmeasurements an
24、d allow for meaningful reports.12. Procedure12.1 Load the sample into the feeder of the flowing streamdigital image analyzer. The analyzer software allows the user tocarry out his measurements quickly and without error. Allmeasuring and analysis parameters are determined initially andset into the co
25、mputer program. Different task files are createdfor different specifications.NOTE 2When assigning sieve ranges to be used in a task file, the usermust use the ASTM mesh sieve choice, not the W. S. Tyler mesh. Thequantity of the material to be measured has to be placed into the funnel ofthe metering
26、feeder. The material handling mechanisms must not restrictor segregate product flow in any way that allows for a non-representativeflow of product through the measurement zone.12.2 After the task file has been defined only a minimalnumber of operative steps are required for carrying out ameasurement
27、. They are: (a) filling a quantity of the material tobe measured into the funnel to the metering feeder, (b) callingthe measurement and choosing the task file, (c) confirming thesuggested comments or entering new comments, (d) startingthe measurement, and (e) reading the result or printing arecord.
28、The measured result is available a few moments afterFIG. 1 Typical ApparatusD7681 11 (2016)2the measurement is completed and can be displayed in manyforms, and be printed and saved with the help of the PC.13. Report13.1 Report the percentage of particles in each size classi-fication.14. Precision an
29、d Bias414.1 PrecisionA round-robin study has been used togenerate a precision statement.14.1.1 The precision of this test method is based on aninterlaboratory study of D7681, Standard Test Method forMeasuring Gradation of Glass Spheres Using a FlowingStream Digital Image Analyzer, conducted in 2008.
30、 A total ofsix laboratories participated in this study. Each of the labs wasasked to report duplicate test results for three different mate-rials. Every “test result” reported represents an individualdetermination. Except for instances where laboratories re-ported fewer replicates or materials, Prac
31、tice E691 was fol-lowed for the design and analysis of the data; the details aregiven in ASTM Research Report RR:D01-1157.14.1.2 Repeatability Limit (r)Two test results obtainedwithin one laboratory shall be judged not equivalent if theydiffer by more than the “r” value for that material; “r”isthein
32、terval representing the critical difference between two testresults for the same material, obtained by the same operatorusing the same equipment on the same day in the samelaboratory.14.1.2.1 Repeatability limits are listed in Tables 1-12.14.1.3 Reproducibility Limit (R)Two test results shall bejudg
33、ed not equivalent if they differ by more than the “R” valuefor that material; “R” is the interval representing the criticaldifference between two test results for the same material,obtained by different operators using different equipment indifferent laboratories.14.1.3.1 Reproducibility limits are
34、listed in Tables 1-12.14.1.4 The above terms (repeatability limit and reproduc-ibility limit) are used as specified in Practice E177.14.1.5 Any judgment in accordance with statements 14.1.2and 14.1.3 would normally have an approximate 95 % prob-ability of being correct, however the precision statics
35、 obtainedin this ILS must not be treated as exact mathematical quantitieswhich are applicable to all circumstances and uses. The limitednumber of laboratories reporting results guarantees that therewill be times when differences greater than predicted by theILS results will arise, sometimes with con
36、siderably greater orsmaller frequency than the 95 % probability limit would imply.Consider the listed precision limits as general guides, and theassociated probability of 95 % only as a rough indicator ofwhat can be expected.14.2 BiasAt the time of the study, there was no referencemade for bias for
37、this test method.15. Keywords15.1 glass beads; gradation; particle size analyzersieve size4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D01-1157. ContactASTM CustomerService at serviceastm.org.TABLE 1 Sieve Size 20 Average Gra
38、ms RetainedMaterialAverageAGrams RetainedStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx Sx SrrSRRType I 0.190 0.044 0.020 0.046 0.057 0.129Type III 0.291 0.258 0.104 0.269 0.291 0.752Type V 0.624 0.298 0.057 0.301 0.161 0.843ATh
39、e average of the laboratories calculated average.D7681 11 (2016)3TABLE 2 Sieve Size 20 Average Grams PassingMaterialAverageAGrams PassingStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx Sx SrrSRRType I 99.810 0.044 0.020 0.046 0.0
40、57 0.129Type III 99.709 0.258 0.104 0.269 0.291 0.752Type V 99.376 0.298 0.057 0.301 0.161 0.843AThe average of the laboratories calculated average.TABLE 3 Sieve Size 30 Average Grams RetainedMaterialAverageAGrams RetainedStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibili
41、tyStandardDeviationReproducibilityLimitx Sx SrrSRRType I 5.917 1.169 0.268 1.184 0.749 3.317Type III 23.987 7.750 8.235 9.694 23.057 27.143Type V 8.728 1.071 0.119 1.074 0.333 3.008AThe average of the laboratories calculated average.TABLE 4 Sieve Size 30 Average Grams PassingMaterialAverageAGrams Pa
42、ssingStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx Sx SrrSRRType I 93.893 1.209 0.271 1.224 0.759 3.428Type III 81.851 9.625 10.318 12.078 28.890 33.817Type V 90.648 1.360 0.113 1.362 0.318 3.814AThe average of the laboratories
43、 calculated average.TABLE 5 Sieve Size 40 Average Grams RetainedMaterialAverageAGrams RetainedStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx Sx SrrSRRType I 28.287 1.790 1.650 2.136 4.621 28.287Type III 51.778 8.190 6.150 9.273
44、17.221 25.965Type V 34.642 9.067 0.398 9.071 1.114 25.400AThe average of the laboratories calculated average.TABLE 6 Sieve Size 40 Average Grams PassingMaterialAverageAGrams PassingStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx
45、Sx SrrSRRType I 65.608 2.067 1.742 2.406 4.879 6.737Type III 81.851 9.625 10.318 12.078 28.890 33.817Type V 56.006 10.402 0.433 10.406 1.212 29.138AThe average of the laboratories calculated average.D7681 11 (2016)4TABLE 7 Sieve Size 50 Average Grams RetainedMaterialAverageAGrams RetainedStandardDev
46、iationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx Sx SrrSRRType I 38.533 2.469 1.450 2.673 4.060 38.533Type III 18.288 7.213 9.918 10.061 27.771 28.170Type V 53.115 9.716 0.441 9.721 1.234 27.220AThe average of the laboratories calculated ave
47、rage.TABLE 8 Sieve Size 50 Average Grams PassingMaterialAverageAGrams PassingStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx Sx SrrSRRType I 27.075 3.888 0.657 3.916 1.840 10.964Type III 11.785 8.537 10.374 11.256 29.048 31.517Ty
48、pe V 2.891 0.756 0.050 0.757 0.139 2.119AThe average of the laboratories calculated average.TABLE 9 Sieve Size 100 Average Grams RetainedMaterialAverageAGrams RetainedStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx Sx SrrSRRType
49、I 24.618 3.485 0.351 3.494 0.982 24.618Type III 3.804 0.514 0.156 0.526 0.438 1.473Type V 2.741 0.748 0.049 0.749 0.138 2.096AThe average of the laboratories calculated average.TABLE 10 Sieve Size 100 Average Grams PassingMaterialAverageAGrams PassingStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx Sx SrrSRRType I 2.457 1.104 0.600 1.183 1.681 3.312Type III 7.981 8.683 10.417 11.386 29.166 31.881Type V 0.150 0.037 0.036 0.045 0.100
