1、Designation: D 4791 05e1Standard Test Method forFlat Particles, Elongated Particles, or Flat and ElongatedParticles in Coarse Aggregate1This standard is issued under the fixed designation D 4791; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.e1NOTEInformation corre
3、cted editorially in Table 3 in August 2007.1. Scope1.1 This test method covers the determination of the per-centages of flat particles, elongated particles, or flat andelongated particles in coarse aggregates.1.2 The values stated in inch-pound units are to be regardedas the standard except in regar
4、d to sieve size and the size ofaggregate, which are given in SI units in accordance withSpecification E11. The SI units in parentheses are for infor-mation purposes only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility
5、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. Referenced Documents2.1 ASTM Standards:2C 125 Terminology Relating to Concrete and ConcreteAggregatesC 136 Test Method for Sieve Analysis of F
6、ine and CoarseAggregatesC 670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsC 702 Practice for Reducing Samples of Aggregate toTesting SizeD75 Practice for Sampling AggregatesE11 Specification for Wire-Cloth and Sieves for TestingPurposes3. Terminolog
7、y3.1 Definitions:3.1.1 flat and elongated particles of aggregatethose par-ticles having a ratio of length to thickness greater than aspecified value.3.1.2 flat or elongated particles of aggregatethose par-ticles of aggregate having a ratio of width to thickness or lengthto width greater than a speci
8、fied value (see TerminologyC 125).3.1.3 lengthmaximum dimension of the particle.3.1.4 thicknessmaximum dimension perpendicular to thelength and width.3.1.5 widthmaximum dimension in the plane perpendicu-lar to the length4. Summary of Test Method4.1 Individual particles of aggregate of specific sieve
9、 sizesare measured to determine the ratios of width to thickness,length to width, or length to thickness.5. Significance and Use5.1 Flat or elongated particles of aggregates, for someconstruction uses, may interfere with consolidation and resultin harsh, difficult to place materials.5.2 This test me
10、thod provides a means for checking com-pliance with specifications that limit such particles or todetermine the relative shape characteristics of coarse aggre-gates.6. Apparatus6.1 The apparatus used shall be equipment suitable fortesting aggregate particles for compliance with the definitionsin 3.1
11、, at the dimensional ratios desired.6.1.1 Proportional Caliper DeviceThe proportional cali-per devices illustrated in Fig. 1, Fig. 2, and Fig. 3 are examplesof devices suitable for this test method. The device illustratedin Fig. 1 and Fig. 2 consists of a base plate with two fixed postsand a swingin
12、g arm mounted between them so that the1This test method is under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.51 onAggregate Tests.Current edition approved July 15, 2005. Published August 2005. Originallyapproved in 1989. Las
13、t previous edition approved in 1999 as D 4791 99.2For 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.1Copyright A
14、STM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.openings between the arms and the posts maintain a constantratio. The axis position can be adjusted to provide the desiredratio of opening dimensions. Fig. 1 illustrates a device onwhich ratios of
15、1:2, 1:3, 1;4, and 1:5 may be set. The deviceillustrated in Fig. 3 contains several fixed posts and has thecapability of measuring various ratios simultaneously.6.1.1.1 Verification of RatioThe ratio settings on theproportional caliper device shall be verified by the use of amachined block, micromet
16、er, or other appropriate device.6.1.2 BalanceThe balance or scales used shall be accurateto 0.5 % of the mass of the sample.7. Sampling7.1 Sample the coarse aggregate in accordance with PracticeD75. The mass of the field sample shall be the mass shown inPractice D75.7.2 Thoroughly mix the sample and
17、 reduce it to an amountsuitable for testing using the applicable procedures described inPractice C 702. The sample for test shall be approximately themass desired when dry and shall be the end result of thereduction. Reduction to an exact predetermined mass shall notbe permitted. The mass of the tes
18、t sample shall conform to thefollowing:Nominal Maximum SizeSquare Openings, mm (in.)Minimum Mass ofTest Sample, kg. (lb)9.5 (38) 1 (2)12.5 (12) 2 (4)19.0 (34)5()25.0 (1) 10 (22)37.5 (112) 15 (33)50 (2) 20 (44)63 (212) 35 (77)75 (3) 60 (130)90 (312) 100 (220)100 (4) 150 (330)112 (412) 200 (440)125 (5
19、) 300 (660)150 (6) 500 (1100)8. Procedure8.1 If determination by mass is required, oven dry thesample to constant mass at a temperature of 230 6 9F (11065C). If determination is by particle count, drying is notnecessary.8.2 Sieve the sample to be tested in accordance with TestMethod C 136. Using the
20、 material retained on the 9.5 mm (38in.) or 4.75 mm (No. 4), as required by the specification beingused, reduce each size fraction present in the amount of 10 %or more of the original sample in accordance with PracticeC 702 until approximately 100 particles are obtained for eachsize fraction require
21、d.8.3 Flat Particle Test and Elongated Particle TestTesteach of the particles in each size fraction, and place in one ofthree groups: (1) flat, (2) elongated, (3) neither flat norelongated.8.3.1 Use the proportional caliper device, positioned at theproper ratio, shown in Fig. 2, as follows:8.3.1.1 F
22、lat Particle TestSet the larger opening equal tothe particle width. The particle is flat if the thickness can beplaced in the smaller opening.8.3.1.2 Elongated Particle TestSet the larger openingequal to the particle length. The particle is elongated if thewidth can be placed within the smaller open
23、ing.FIG. 1 Proportional CaliperTABLE 2a. Test for elongationb. Test for flatnessMetric Equivalentsin. mm in. mm in. mm18 3.278 21.2 212 64.0316 4.8 1 25.4 278 72.014 6.3 1116 27.0 334 96.0516 7.9 112 38.0 8 207.038 9.5 158 41.0 16 414.0FIG. 2 Use of Proportional CaliperD479105e128.3.2 After the part
24、icles have been classified into the groupdescribed in 8.3, determine the proportion of the sample ineach group by either count or by mass, as required.8.4 Flat and Elongated Particle TestTest each of theparticles in each size fraction and place in one of two groups:(1) flat and elongated or (2) not
25、flat and elongated.8.4.1 Use the proportional caliper device, set at the desiredratio.8.4.2 Measurement:8.4.2.1 On proportional caliper devices similar to the de-vices shown in Fig. 1 and Fig. 2, set the larger opening equalto the length of the particle. The particle is flat and elongatedif the part
26、icle, when oriented to measure its thickness, can passcompletely through the smaller opening of the caliper.8.4.2.2 On calipers similar to the one described in Fig. 3, setthe minimum dimension of the proportional caliper device suchthat the particle, when oriented to measure its thickness, passessnu
27、gly between the post and swing arm. The particle is flat andelongated if the particle, when oriented to measure its length,fails to pass the desired large opening of the proportionalcaliper device.8.4.3 After the particles have been classified into the groupsdescribed in 8.4, determine the proportio
28、n of the sample ineach group by count or mass, as required.9. Calculation9.1 Calculate the percentage of flat and elongated particlesto the nearest 1 % for each sieve size greater than 9.5 mm (38in.) or 4.75 (No. 4), as required.10. Report10.1 Include the following information in the report:10.1.1 I
29、dentification of the coarse aggregate tested, and10.1.2 Grading of the aggregate sample, showing percent-age retained on each sieve.10.1.3 For flat particle tests and elongated particle tests:10.1.3.1 Number of particles in each sieve size tested,10.1.3.2 Percentages, calculated by number or by mass
30、, orboth, for: (1) flat particles, (2) elongated particles, and (3) totalflat particles and elongated particles for each sieve size tested,and10.1.3.3 The dimensional ratios used in the tests.10.1.4 For flat and elongated particle tests:10.1.4.1 Number of particles in each sieve size tested,10.1.4.2
31、 Percentages, calculated by number or by mass, orboth, for flat and elongated particles for each sieve size tested,10.1.4.3 The dimensional ratio used in the tests, and10.1.5 When required, weighted average percentages basedon the actual or assumed proportions of the various sieve sizestested. Repor
32、t the grading used for the weighted average ifdifferent from that in 10.1.2.11. Precision and Bias11.1 PrecisionThe precision values listed in Table 1,FIG. 3 Proportional CaliperTABLE 1 19.0-mm to 12.5-mm Flat and Elongated (Percent)Precision Test Result (%) (1S) % (D2S) %Single Operator 2.7 51.2 14
33、4.8Multilaboratory 88.5 250.3D479105e13Table 2, and Table 3 are averages obtained from AMRLproficiency samples used in the Aggregate Proficiency SampleProgram (see Note 1). The 1S % and D2S % limits providedare described in Practice C 670.NOTE 1A 3 to 1 ratio was used.11.2 BiasSince there is no acce
34、pted reference materialsuitable for determining the bias for this test method, nostatement on bias is being made.12. Keywords12.1 aggregates; coarse aggregates; particle shapeASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentio
35、nedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee an
36、d must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting o
37、f theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box
38、 C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE
39、2 12.5-mm to 9.5-mm Flat and Elongated (Percent)Precision Test Result (%) (1S) % (D2S) %Single Operator 34.9 22.9 64.7Multilaboratory 43.0 121.8TABLE 3 9.5-mm to 4.75-mm Flat and Elongated (Percent)Precision Test Result (%) (1S) % (D2S) %Single Operator 24.1 19.0 53.6Multilaboratory 46.1 130.3Value correctedD479105e14
