1、Designation: D5821 13Standard Test Method forDetermining the Percentage of Fractured Particles in CoarseAggregate1This standard is issued under the fixed designation D5821; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f 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 thepercentage, by mass or by count, of a coarse aggregate samplethat co
3、nsists of fractured particles meeting specified require-ments.1.2 The values stated in SI units are to be regarded as thestandard. The values in parentheses are provided for informa-tion only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It
4、 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. Referenced Documents2.1 ASTM Standards:2C136 Test Method for Sieve Analysis of Fine and CoarseAggregatesC702 Practice fo
5、r Reducing Samples ofAggregate to TestingSizeD8 Terminology Relating to Materials for Roads and Pave-mentsD75 Practice for Sampling AggregatesE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3. Terminology3.1 Definitions:3.1.1 fractured face, nan angular, rough, or broken sur-face of
6、an aggregate particle created by crushing, by otherartificial means, or by nature (see Terminology D8).3.1.1.1 Discussionfor this standard, a face will be consid-ered a “fractured face” only if it has a projected area at least aslarge as one quarter of the maximum projected area (maximumcross-sectio
7、nal area) of the particle (this excludes small nicks,see Fig. 1) and the face has sharp or slightly blunt edges.3.1.2 fractured particle, na particle of aggregate having atleast the minimum number of fractured faces specified (usuallyone or two).4. Significance and Use4.1 Some specifications contain
8、 requirements relating topercentage of fractured particles in coarse aggregates. Onepurpose of such requirements is to maximize shear strength byincreasing inter-particle friction in either bound or unboundaggregate mixtures. Another purpose is to provide stability forsurface treatment aggregates an
9、d to provide increased frictionand texture for aggregates used in pavement surface courses.This test method provides a standard procedure for determiningthe acceptability of coarse aggregate with respect to suchrequirements.4.2 Specifications differ as to the number of fractured facesrequired on a f
10、ractured particle, and they also differ as towhether percentage by mass or percentage by particle countshall be used. If the specification does not specify, use thecriterion of at least one fractured face and calculate percentageby mass.5. Apparatus5.1 BalanceA balance or scale accurate and readable
11、 towithin 0.1 % of the test sample mass at any point within therange of use.5.2 SievesSieves conforming to Specification E11.5.3 SplitterA sample splitter suitable for dividing fieldsamples into test portion sizes in accordance with PracticeC702.5.4 SpatulaA spatula or similar tool to aid in sorting
12、aggregate particles.6. Sampling6.1 Sample the aggregate in accordance with Practice D75.1This 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 Dec. 1, 2013. Publi
13、shed January 2014. Originallyapproved in 1995. Last previous edition approved in 2006 as D5821 01 (2006).DOI: 10.1520/D5821-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information
14、, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17. Sample Preparation7.1 Dry the sample sufficiently to obtain a clean separationof fine and coarse material in the siev
15、ing operation. Sieve thesample over the 4.75-mm (No. 4) sieve, or other specified sievefor retaining material for this test, in accordance with TestMethod C136 and then reduce the portion retained on the sieveusing a splitter in accordance with Practice C702 to appropriatesize for test.7.2 The mass
16、of the test sample shall be at least largeenough so that the largest particle is not more than 1 % of thesample mass; or the test sample shall be at least as large asindicated below, whichever is smaller:Nominal Maximum SizeSquareOpenings, mm (in.)Minimum Test SampleMass, g(Approx. lb)9.5 (38) 200 (
17、0.5)12.5 (12) 500 (1)19.0 (34) 1500 (3)25.0 (1) 3000 (6.5)37.5 (112) 7500 (16.5)50.0 (2) 15 000 (33)63.0 (212) 30 000 (66)75.0 (3) 60 000 (132)90.0 (312) 90 000 (198)7.3 For aggregate with a nominal maximum size of 19.0 mm(34 in.) or larger, where the fracture particle content is to bedetermined for
18、 material retained on the 4.75-mm (No. 4) orsmaller sieve, the test sample may be separated on the 9.5-mm(38-in.) sieve. The portion passing the 9.5-mm (38-in.) sievemay then be further reduced, in accordance with Practice C702,to a minimum of 200 g (0.5 lb). This will reduce the number ofparticles
19、to be separated during the procedure. In this case,percent fractured particles is determined on each portion; anda weighted average percentage of fractured particles is calcu-lated based on the mass of each of the portions to reflect thetotal percentage of fractured particles in the entire sample.8.
20、 Procedure8.1 Wash the sample over the sieve designated for determi-nation of fractured particles to remove any remaining finematerial, and dry to constant mass. Determine the mass of thetest sample, and any subsequent determinations of mass, to thenearest 0.1 % of the original dry sample mass.8.2 S
21、pread the dried test sample on a clean flat surface largeenough to permit careful inspection of each particle. To verifythat a particle meets the fracture criteria, hold the aggregateparticle so that the face is viewed directly. If the faceconstitutes at least one quarter of the maximum cross-sectio
22、nalarea of the rock particle, consider it a fractured face.8.3 Using the spatula or similar tool separate into twocategories: (1) fractured particles based on whether the particlehas the required number of fractured faces, and (2) particles notmeeting the specified criteria. Use Figs. 2-7 to aid in
23、thisdetermination. Be aware that some of the particles in Figs. 2-4do show more than one fractured face. If the required numberof fractured faces is not given in the applicable specifications,the determination will be made on the basis of a minimum ofone fractured face.8.4 Determine the mass or coun
24、t of particles in the fracturedparticle category and the mass or count of the particles notmeeting the specified fracture criteria. Use mass to calculatepercent fractured particles unless percentage by particle countis specified.8.5 If more than one number of fractured faces is specified(for example
25、, 70 % with one or more fractured faces and 40 %FIG. 1 Schematic of a Fractured Particle with One Fractured FaceD5821 132with two or more fractured faces), repeat the procedure on thesame sample for each requirement.9. Report9.1 Report the mass percentage or count percentage ofparticles with the spe
26、cified number(s) of fractured faces to thenearest 1 % in accordance with the following:P 5 F/F1N!# 3100 (1)where:P = percentage of particles with the specified number offractured faces,F = mass or count of fractured particles with at least thespecified number of fractured faces, andN = mass or count
27、 of particles in the non-fractured categorynot meeting the fractured particle criteria.9.2 Report the specified fracture criteria against which thesample was evaluated.9.3 Report the total mass in grams of the coarse aggregatesample tested.9.4 Report the sieve on which the test sample was retainedat
28、 the start of the test.9.5 Report whether the percentage of fractured particles wasdetermined by mass or by particle count.10. Precision and Bias10.1 PrecisionThe Ontario Ministry of Transportationreported that in a formal study of 34 well-trained observers oftwo samples of partly-fractured gravel (
29、proportion of fracturedparticles = 76 %) the average standard deviation was found tobe 5.2 %. Therefore, the difference in results between twowell-trained observers, on samples of the same material shouldnot exceed 14.7 % of their average, nineteen times in twenty.NOTE 1When a mixture of trained and
30、 untrained observers conductedthis test, the average multi-operator standard deviation increased to about7.6 %.FIG. 2 Fractured Particle (Sharp Edges, Rough Surfaces)FIG. 3 Fractured Particle (Sharp Edges, Smooth Surfaces)D5821 13310.2 BiasThis test method has no bias because the valuesdetermined ca
31、n be defined only in terms of the test method.11. Keywords11.1 aggregate; crushed aggregate; crushed gravel; crushedparticles; fractured faces; fractured particlesFIG. 4 a) Fractured Particle (Round Edges, Rough Surfaces)FIG. 4 b) Fractured Particle (Round Edges, Rough Surfaces) (continued)FIG. 4 c)
32、 Fractured Particle (Round Edges, Rough Surfaces) (continued)D5821 134FIG. 5 Fractured Particle (Center) Flanked by Two Non-Fractured Particles (Chipped Only)FIG. 6 Non-Fractured Particle (Round Edges, Smooth Surfaces)D5821 135ASTM International takes no position respecting the validity of any paten
33、t 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 standard is subject to revision a
34、t 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 International Headquarters. Your commen
35、ts 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 below.This standard is copyrighted
36、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 (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/).FIG. 7 Non-Fractured Particle (Rounded Particles, Smooth Surfaces)D5821 136
