ASTM D4791-19(2023)
(Test Method)Standard Test Method for Flat Particles, Elongated Particles, or Flat and Elongated Particles in Coarse Aggregate
Standard Test Method for Flat Particles, Elongated Particles, or Flat and Elongated Particles in Coarse Aggregate
SIGNIFICANCE AND USE
5.1 The particle shape of coarse aggregates influences the properties of some construction materials and may affect their placement and consolidation.
5.2 This test method provides a means for checking compliance with specifications that limit such particles or to determine the relative shape characteristics of coarse aggregates.
SCOPE
1.1 This test method covers the determination of the percentages of flat particles, elongated particles, or flat and elongated 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 developed prior to Superpave and is intended for all non-Superpave applications. Method B is a comparison of the maximum particle dimension to the minimum particle dimension and is intended for use with Superpave specifications.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.2.1 Exception (regarding sieves, per Specification E11)—The values stated in SI units shall be considered standard for the dimensions of the wire cloth openings and the diameter of the wires used in the wire cloth. When sieve mesh sizes are referenced, the alternate inch-pound designations are provided for information purposes and enclosed in parentheses.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4791 − 19 (Reapproved 2023)
Standard Test Method for
Flat Particles, Elongated Particles, or Flat and Elongated
Particles in Coarse Aggregate
This standard is issued under the fixed designation D4791; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method covers the determination of the per-
C136/C136M Test Method for Sieve Analysis of Fine and
centages of flat particles, elongated particles, or flat and
Coarse Aggregates
elongated particles in coarse aggregates. Two procedures,
C670 Practice for Preparing Precision and Bias Statements
Method A and Method B, are presented in this standard.
for Test Methods for Construction Materials
Method A is a reflection of the original procedure as developed
C702/C702M Practice for Reducing Samples of Aggregate
prior to Superpave and is intended for all non-Superpave
to Testing Size
applications. Method B is a comparison of the maximum
D75/D75M Practice for Sampling Aggregates
particle dimension to the minimum particle dimension and is
E11 Specification for Woven Wire Test Sieve Cloth and Test
intended for use with Superpave specifications.
Sieves
E177 Practice for Use of the Terms Precision and Bias in
1.2 The values stated in inch-pound units are to be regarded
ASTM Test Methods
as standard. The values given in parentheses are mathematical
E691 Practice for Conducting an Interlaboratory Study to
conversions to SI units that are provided for information only
Determine the Precision of a Test Method
and are not considered standard.
1.2.1 Exception (regarding sieves, per Specification E11)—
3. Terminology
The values stated in SI units shall be considered standard for
3.1 Definitions:
the dimensions of the wire cloth openings and the diameter of
3.1.1 elongated particles of aggregate—those particles of
the wires used in the wire cloth. When sieve mesh sizes are
aggregate having a ratio of length to width greater than a
referenced, the alternate inch-pound designations are provided
specified value.
for information purposes and enclosed in parentheses.
3.1.2 flat and elongated particles of aggregate—those par-
1.3 This standard does not purport to address all of the
ticles having a ratio of length to thickness greater than a
safety concerns, if any, associated with its use. It is the
specified value.
responsibility of the user of this standard to establish appro-
3.1.3 flat particles of aggregate—those particles of aggre-
priate safety, health, and environmental practices and deter-
gate having a ratio of width to thickness greater than a specified
mine the applicability of regulatory limitations prior to use.
value.
1.4 This international standard was developed in accor-
3.1.4 length—maximum dimension of the particle, as illus-
dance with internationally recognized principles on standard-
trated in Fig. 1.
ization established in the Decision on Principles for the
3.1.5 thickness—minimum dimension of particle. It is the
Development of International Standards, Guides and Recom-
maximum dimension perpendicular to the length and width as
mendations issued by the World Trade Organization Technical
illustrated in Fig. 1.
Barriers to Trade (TBT) Committee.
3.1.6 width—intermediate dimension of the particle. It is the
maximum dimension in the plane perpendicular to the length
This test method is under the jurisdiction of ASTM Committee D04 on Road
and Paving Materials and is the direct responsibility of Subcommittee D04.51 on
Aggregate Tests. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2023. Published November 2023. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1989. Last previous edition approved in 2019 as D4791 – 19. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D4791-19R23. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4791 − 19 (2023)
FIG. 1 Particle Dimensions
and thickness. The width dimensions is greater than or equal to 7.2 Thoroughly mix the sample and reduce it to an amount
the thickness as illustrated in Fig. 1. suitable for testing using the applicable procedures described in
Practice C702/C702M. The sample for test shall be approxi-
4. Summary of Test Method mately the mass desired when dry and shall be the end result of
the reduction. Reduction to an exact predetermined mass shall
4.1 Individual particles of aggregate of specific sieve sizes
not be permitted. The mass of the test sample shall conform to
are measured to determine the ratios of width to thickness,
the following:
length to width, or length to thickness.
Nominal Maximum Size Minimum Mass of
Square Openings, in. (mm) Test Sample, lb (kg)
5. Significance and Use
⁄8 (9.5) 2 (1)
⁄2 (12.5) 4 (2)
5.1 The particle shape of coarse aggregates influences the
⁄4 (19.0) 11 (5)
properties of some construction materials and may affect their
1 (25.0) 22 (10)
placement and consolidation. 1 ⁄2 (37.5) 33 (15)
2 (50) 44 (20)
5.2 This test method provides a means for checking com-
2 ⁄2 (63) 77 (35)
3 (75) 130 (60)
pliance with specifications that limit such particles or to
3 ⁄2 (90) 220 (100)
determine the relative shape characteristics of coarse aggre-
4 (100) 330 (150)
gates.
4 ⁄2 (112) 440 (200)
5 (125) 660 (300)
6 (150) 1100 (500)
6. Apparatus
8. Procedure
6.1 The apparatus used shall be equipment suitable for
testing aggregate particles for compliance with the definitions
8.1 If determination by mass is required, oven dry the
in 3.1, at the dimensional ratios desired.
sample to constant mass at a temperature of 230 6 9 °F (110
6.1.1 Proportional Caliper Device—The proportional cali-
6 5 °C). If determination is by particle count, drying is not
per devices illustrated in Figs. 2 and 3 are examples of devices
necessary.
suitable for this test method. The device illustrated in Fig. 2
8.2 Sieve the sample to be tested in accordance with Test
consists of a base plate with two fixed posts and a swinging
Method C136/C136M. Using the material retained on the ⁄8 in.
arm mounted between them so that the openings between the
(9.5 mm) or No. 4 (4.75 mm), as required by the specification
arms and the posts maintain a constant ratio. The axis position
being used, reduce each size fraction present in the amount of
can be adjusted to provide the desired ratio of opening
10 % or more of the original sample in accordance with
dimensions. Fig. 2 illustrates a device on which ratios of 1:2,
Practice C702/C702M until approximately 100 particles are
1:3, and 1:5 may be set. The device illustrated in Fig. 3
obtained for each size fraction required. Size fractions contain-
contains several fixed posts and has the capability of measuring
ing less than 10 % by mass of the original total sample mass are
various ratios simultaneously. See Note 1.
not tested and can be discarded.
6.1.1.1 Verification of Ratio—The ratio settings on the
8.3 Method A—Test each of the particles in each size
proportional caliper device shall be verified by the use of a
fraction, and place in one of four groups: (1) flat particles, (2)
machined block, micrometer, or other appropriate device.
elongated particles, (3) particles that meet the criteria of both
6.1.2 Balance—The balance or scales used shall be accurate
Group 1 and Group 2, and (4) neither flat nor elongated
to 0.5 % of the mass of the sample.
particles that do not meet the criteria of either Group 1 or
NOTE 1—Figs. 2 and 3 provide examples of possible devices that may
be used for this test. Other devices may be found suitable if they are able
Group 2. Each particle shall be subjected to the flat particle test
to meet the verification requirements listed in 6.1.1.1.
and elongated 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,
7. Sampling
the particle is placed in the “flat” group. If is determined that
7.1 Sample the coarse aggregate in accordance with Practice the particle is not flat, but is elongated, the particle is placed in
D75/D75M. The mass of the field sample shall be the mass the “elongated” group. In some cases, it may be possible for a
shown in Practice D75/D75M. particle to meet the criteria of both a flat particle and an
D4791 − 19 (2023)
Metric Equivalents
in. (mm) in. (mm
1 5
⁄8 (3.2) 1 ⁄8 (41.0)
3 3
⁄16 (4.8) 1 ⁄4 (44.5)
⁄4 (6.3) 2 (50.8)
5 1
⁄16 (7.9) 2 ⁄2 (64.0)
3 7
⁄8 (9.5) 2 ⁄8 (72.0)
3 3
⁄4 (19.1) 3 ⁄4 (96.0)
⁄8 (21.2) 8 (207.0)
1 (25.4) 12 (304.8)
1 ⁄16 (27.0) 13 (330.2)
1 ⁄2 (38.0) 16 (414.0)
FIG. 2 Proportional Caliper
D4791 − 19 (2023)
FIG. 3 Proportional Caliper
elongated particle. In this case the particle is placed in the 9. Calculation
“particles that meet the criteria of both Group 1 and Group 2”
9.1 Calculate the percentage of particles in each group to the
group. If the particle is not flat and is not elongated, it is placed
nearest 1 % for each size fraction tested greater than ⁄8 in.
in the “particles that do not meet the criteria of either Group 1
(9.5 mm) or No. 4 (4.75 mm), as required.
or Group 2” group.
8.3.1 Use the proportional caliper device, positioned at the
10. Report
proper ratio, shown in Fig. 4, as follows:
10.1 Include the following information in the report:
8.3.1.1 Flat Particle Test—Set the larger opening equal to
the maximum particle width. The particle is flat if the maxi-
10.1.1 Identification of the coarse aggregate tested, and
mum thickness can be placed though the smaller opening.
10.1.2 Grading of the original aggregate sample, showing
8.3.1.2 Elongated Particle Test—Se
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