1、Designation: D4791 10Standard Test Method forFlat Particles, Elongated Particles, or Flat and ElongatedParticles in Coarse Aggregate1This standard is issued under the fixed designation D4791; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method
3、 covers the determination of the per-centages of flat particles, elongated particles, or flat andelongated particles in coarse aggregates. Two procedures,Method A and Method B, are presented in this standard.Method A is a reflection of the original procedure as developedprior to Superpave and is int
4、ended for all non-Superpaveapplications. Method B is a comparison of the maximumparticle dimension to the minimum particle dimension and isintended for use with Superpave specifications.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathe
5、maticalconversions to SI units that are provided for information onlyand are not considered standard.1.2.1 Exception (Regarding sieves, per Specification E11)The values stated in SI units shall be considered standard forthe dimensions of the wire cloth openings and the diameter ofthe wires used in t
6、he wire cloth. When sieve mesh sizes arereferenced, the alternate inch-pound designations are providedfor information purposes and enclosed in parenthesis.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of
7、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:2C136 Test Method for Sieve Analysis of Fine and CoarseAggregatesC670 Practice for Preparing Precision and Bias Statem
8、entsfor Test Methods for Construction MaterialsC702 Practice for Reducing Samples of Aggregate to Test-ing SizeD75 Practice for Sampling AggregatesE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3. Terminology3.1 Definitions:3.1.1 elongated particles of aggregatethose particles ofagg
9、regate having a ratio of length to width greater than aspecified value.3.1.2 flat and elongated particles of aggregatethose par-ticles having a ratio of length to thickness greater than aspecified value.3.1.3 flat particles of aggregatethose particles of aggre-gate having a ratio of width to thickne
10、ss greater than a specifiedvalue.3.1.4 lengthmaximum dimension of the particle, as illus-trated in Fig. 1.3.1.5 thicknessminimum dimension of particle. It is themaximum dimension perpendicular to the length and width asillustrated in Fig. 1.3.1.6 widthintermediate dimension of the particle. It is th
11、emaximum dimension in the plane perpendicular to the lengthand thickness. The width dimensions is greater than or equal tothe thickness as illustrated in Fig. 1.4. Summary of Test Method4.1 Individual particles of aggregate of specific sieve sizesare measured to determine the ratios of width to thic
12、kness,length to width, or length to thickness.5. Significance and Use5.1 The particles shape of course aggregates influences theproperties of some construction materials and may affect theirplacement and consolidation.1This test method is under the jurisdiction of ASTM Committee D04 on Roadand Pavin
13、g Materials and is the direct responsibility of Subcommittee D04.51 onAggregate Tests.Current edition approved June 1, 2010. Published October 2010. Originallyapproved in 1989. Last previous edition approved in 2005 as D4791 05e1. DOI:10.1520/D4791-10.2For referenced ASTM standards, visit the ASTM w
14、ebsite, 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 ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United S
15、tates.5.2 This test method 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
16、 the definitionsin 3.1, at the dimensional ratios desired.6.1.1 Proportional Caliper DeviceThe proportional cali-per devices illustrated in Fig. 2 and Fig. 3 are examples ofdevices suitable for this test method. The device illustrated inFig. 2 and consists of a base plate with two fixed posts and as
17、winging arm mounted between them so that the openingsbetween the arms and the posts maintain a constant ratio. Theaxis position can be adjusted to provide the desired ratio ofopening dimensions. Fig. 2 illustrates a device on which ratiosof 1:2, 1:3, and 1:5 may be set. The device illustrated in Fig
18、. 3contains several fixed posts and has the capability of measuringvarious ratios simultaneously. See Note 16.1.1.1 Verification of RatioThe ratio settings on theproportional caliper device shall be verified by the use of amachined block, micrometer, or other appropriate device.6.1.2 BalanceThe bala
19、nce or scales used shall be accurateto 0.5 % of the mass of the sample.NOTE 1Figs. 2 and 3 provide examples of possible devices that maybe used for this test. Other devices may be found suitable if they are ableto meet the verification requirements listed in 6.1.1.1.7. Sampling7.1 Sample the coarse
20、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 reduce it to an amountsuitable for testing using the applicable procedures described inPractice C702. The sample for test shall be approximately themass des
21、ired when dry and shall be the end result of thereduction. Reduction to an exact predetermined mass shall notbe permitted. The mass of the test sample shall conform to thefollowing:Nominal Maximum SizeSquare Openings, in. (mm)Minimum Mass ofTest Sample, lb (kg)38 (9.5 ) 2 (1)12 (12.5) 4 (2)34 (19.0)
22、 11 (5)1 (25.0) 22 (10)112 (37.5) 33 (15)2(50) 44 (20)212 (63) 77 (35)3 (75) 130 (60)312 (90) 220 (100)4 (100) 330 (150)412 (112) 440 (200)5 (125) 660 (300)6 (150) 1100 (500)8. Procedure8.1 If determination by mass is required, oven dry thesample to constant mass at a temperature of 230 6 9F (11065C
23、). If determination is by particle count, drying is notnecessary.8.2 Sieve the sample to be tested in accordance with TestMethod C136. Using the material retained on the38 in. (9.5mm) or No. 4 (4.75 mm), as required by the specification beingused, reduce each size fraction present in the amount of 1
24、0 %or more of the original sample in accordance with PracticeC702 until approximately 100 particles are obtained for eachsize fraction required. Size fractions containing less than 10%by mass of the original total sample mass are not tested and canbe discarded.8.3 Method ATest each of the particles
25、in each sizefraction, and place in one of four groups: (1) flat particles,(2)elongated particles, (3) particles that meet the criteria of bothgroup (1) and group (2); (4) neither flat nor elongatedparticlesthat do not meet the criteria of either group (1) or group (2).Each particle shall be subjecte
26、d to the Flat Particle Test andElongated Particle Test in accordance with 8.3.1.1 and 8.3.1.2.If the particle is determined to be flat but not elongated, theparticle is placed in the “flat” group. If is determined that theparticle is not flat, but is elongated, the particle is placed in the“elongate
27、d” group. In some cases it may be possible for aparticle to meet the criteria of both a flat particle and anelongated particle. In this case the particle is placed in the“particles that meet the criteria of both group (1) and group(2)” group. If the particle is not flat and is not elongated, it isFI
28、G. 1 Particle DimensionsD4791 102Metric Equivalentsin. (mm) in. (mm18 (3.2) 158 (41.0)316 (4.8) 134 (44.5)14 (6.3) 2 (50.8)516 (7.9) 212 (64.0)38 (9.5) 278 (72.0)34 (19.1) 334 (96.0)78 (21.2) 8 (207.0)1 (25.4) 12 (304.8)1116 (27.0) 13 (330.2)112 (38.0) 16 (414.0)FIG. 2 Proportional CaliperD4791 103p
29、laced in the “particles that do not meet the criteria of eithergroup (1) or group (2)” group.8.3.1 Use the proportional caliper device, positioned at theproper ratio, shown in Fig. 4, as follows:8.3.1.1 Flat Particle TestSet the larger opening equal tothe maximum particle width. The particle is flat
30、 if the maxi-mum thickness can be placed though the smaller opening.8.3.1.2 Elongated Particle TestSet the larger openingequal to the maximum particle length. The particle is elongatedif the maximum width can be placed through the smalleropening.8.3.2 After each of the particles have been classified
31、 intoone of the groups described in 8.3, determine the proportion ofthe sample in each group by either count or by mass, asrequired.8.4 Method BTest each of the particles in each sizefraction and place in one of two groups: (1) flat and elongatedor (2) not flat and elongated.8.4.1 Use the proportion
32、al caliper device, set at the desiredratio as shown in Fig. 4, as follows.8.4.1.1 Flat and Elongated Particle TestSet the largeropening equal to the maximum particle length. The particle isconsidered flat and elongated if the maximum thickness can beplaced through the smaller opening.8.4.2 After the
33、 particles have been classified into the groupsdescribed in 8.4, determine the proportion of the sample ineach group by count or mass, as required.9. Calculation9.1 Calculate the percentage of particles in each group to thenearest 1 % for each size fraction tested greater than38 in. (9.5mm) or No. 4
34、 (4.75 mm), as required.10. Report10.1 Include the following information in the report:10.1.1 Identification of the coarse aggregate tested, and10.1.2 Grading of the original aggregate sample, showingpercentage retained on each sieve.10.1.3 For Method A:10.1.3.1 Number of particles in each sieve siz
35、e tested,10.1.3.2 Percentages, calculated by number or by mass, orboth, for each group: (1) flat particles, (2) elongated particles,and (3) particles that meet the criteria of both group (1) andgroup (2); (4) particles that do not meet the criteria of eithergroup (1) or group (2), and10.1.3.3 The di
36、mensional ratios used in the tests.10.1.4 For Method B:10.1.4.1 Number of particles in each sieve size tested,10.1.4.2 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 re
37、quired, weighted average percentages basedon the actual or assumed proportions of the various sieve sizestested. Report 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,Table 2, and Table 3 are averag
38、es obtained from AMRLproficiency samples used in the Aggregate Proficiency SampleProgram (see Note 2). The 1S % and D2S % limits providedare described in Practice C670.NOTE 2A 1:3 ratio was used.FIG. 3 Proportional CaliperD4791 10411.2 BiasSince there is no accepted reference materialsuitable for de
39、termining the bias for this test method, nostatement on bias is being made.12. Keywords12.1 aggregates; coarse aggregates; particle shapea. Test for flatnessb. Test for elongationc. Test for elongation and flatnessFIG. 4 Use of Proportional CaliperTABLE 1 19.0-mm to 12.5-mm Flat and Elongated (Perce
40、nt)Precision Test Result (%) (1S) % (D2S) %Single Operator 2.7 51.2 144.8Multilaboratory 88.5 250.3TABLE 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 43.0 121.8D4791 105ASTM International takes no position respe
41、cting the validity of any patent rights asserted in connection with any item mentionedin 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 st
42、andard is subject to revision at any time by the responsible technical committee and 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 Internat
43、ional Headquarters. Your comments will receive careful consideration at a meeting of 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 belo
44、w.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box 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 (
45、fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).TABLE 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 correctedD4791 106
