1、Designation: D 7681 11Standard Test Method forMeasuring Gradation of Glass Spheres Using a FlowingStream Digital Image Analyzer1This standard is issued under the fixed designation D 7681; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, 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
3、 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 agenc
4、ypavement 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 a
5、re 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 regulatory limitations
6、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 Standards:3AASHTO M247-
7、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 countin
8、g 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”
9、 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 a
10、nd 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
11、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 c
12、haracterization of thegradation (size distribution) 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 d
13、istri-bution) of glass beads for pavement markings, those arebeyond the scope of this standard.1This 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.Curren
14、t 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 the standards Document Summary page on
15、the 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Unite
16、d States.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 decrease to 50 % maximumrelative humidity at a temperature of 40C.6.1.3 Height of installation and oper
17、ation 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 indoor or outdoo
18、r 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 required safety pre-cautions.8. Sampling, Test Specimens, and Test Units8.1 Obtain a minimum of ap
19、proximately 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 M247-08,75to125gsamples shall be used.8.2 In order to obtain representative samples when sam-pling from p
20、ackaged 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 used.10. Calibration and Standardization10.1 The particle analyzer, in most cases, will be calibrated
21、by 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 this case, follow the calibration proceduresas outlined in the manufacturers instruction manual.11.
22、 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 orsuitable container.11.1.3 Assure glass beads are moisture free and free flow-ing.NOTE 1Check with instru
23、ment 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 and allow for meaningful reports.12. Procedure12.1 Load the sample into the feeder of the flowing stre
24、amdigital 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 computer program. Different task files are createdfor different specifications.NOTE 2When assigning si
25、eve 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 feeder. The material handling mechanisms must not restrictor segregate product flow in any way that
26、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. They are: (a) filling a quantity of the material tobe measured into the funnel to the metering fee
27、der, (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. The measured result is available a few moments afterthe measurement is completed and can be displaye
28、d 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.FIG. 1 Typical ApparatusD7681112TABLE 1 Sieve Size 20 Average Grams RetainedMaterialAverageAGrams RetainedStandard DeviationRepeatabilityStandardDeviationRe
29、peatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx S x 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 0.843AThe average of the laboratories calculated average.TABLE 2 Sieve Size 20 Average Grams Pass
30、ingMaterialAverageAGrams PassingStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx S x SrrSRRType I 99.810 0.044 0.020 0.046 0.057 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 ave
31、rage of the laboratories calculated average.TABLE 3 Sieve Size 30 Average Grams RetainedMaterialAverageAGrams RetainedStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx S x SrrSRRType I 5.917 1.169 0.268 1.184 0.749 3.317Type III 23
32、.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 PassingStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationR
33、eproducibilityLimitx S x 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 calculated average.TABLE 5 Sieve Size 40 Average Grams RetainedMaterialAverageAGrams RetainedStandard
34、DeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx S x SrrSRRType I 28.287 1.790 1.650 2.136 4.621 28.287Type III 51.778 8.190 6.150 9.273 17.221 25.965Type V 34.642 9.067 0.398 9.071 1.114 25.400AThe average of the laboratories calculated
35、average.TABLE 6 Sieve Size 40 Average Grams PassingMaterialAverageAGrams PassingStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx S x 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 33.81
36、7Type V 56.006 10.402 0.433 10.406 1.212 29.138AThe average of the laboratories calculated average.D7681113TABLE 7 Sieve Size 50 Average Grams RetainedMaterialAverageAGrams RetainedStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx
37、S x 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 average.TABLE 8 Sieve Size 50 Average Grams PassingMaterialAverageAGrams PassingStandardDeviationRepeatability
38、StandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx S x 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 31.517Type V 2.891 0.756 0.050 0.757 0.139 2.119AThe average of the laboratories calculated average.TABLE 9 Sieve
39、Size 100 Average Grams RetainedMaterialAverageAGrams RetainedStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx S x SrrSRRType 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 0.0
40、49 0.749 0.138 2.096AThe average of the laboratories calculated average.TABLE 10 Sieve Size 100 Average Grams PassingMaterialAverageAGrams PassingStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx S x SrrSRRType I 2.457 1.104 0.600
41、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 0.126AThe average of the laboratories calculated average.TABLE 11 Sieve Size 100 Average Grams RetainedMaterialAverageAGrams RetainedStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimit
42、ReproducibilityStandardDeviationReproducibilityLimitx S x SrrSRRType I 2.154 1.413 0.404 1.441 1.131 2.154Type III 1.852 3.386 4.570 4.680 12.795 13.104Type V 0.146 0.037 0.046 0.049 0.130 0.138AThe average of the laboratories calculated average.TABLE 12 Sieve Size 100 Average Grams PassingMaterialA
43、verageAGrams PassingStandardDeviationRepeatabilityStandardDeviationRepeatabilityLimitReproducibilityStandardDeviationReproducibilityLimitx S x SrrSRRType I 0.000 0.000 0.000 0.000 0.000 0.000Type III 0.000 0.000 0.000 0.000 0.000 0.000Type V 0.000 0.000 0.000 0.000 0.000 0.000AThe average of the lab
44、oratories calculated average.D768111414. Precision and 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 Flo
45、wingStream Digital Image Analyzer, conducted in 2008. 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 labor
46、atories re-ported fewer replicates or materials, Practice E691 was fol-lowed for the design and analysis of the data; the details aregiven in ASTM Research Report D011157.14.1.2 Repeatability Limit (r)Two test results obtainedwithin one laboratory shall be judged not equivalent if theydiffer by more
47、 than the “r” value for that material; “r”istheinterval 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 Repro
48、ducibility Limit (R)Two test results shall bejudged 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
49、laboratories.14.1.3.1 Reproducibility limits are 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 obtainedin this ILS must not be treated as exact mathematical quantitieswhich are applicable to all circumstances and uses. The limitednumber of laboratories reporting results
