ASTM D4751-99a

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Designation:D4751–99a
Standard Test Method for
Determining Apparent Opening Size of a Geotextile
This standard is issued under the fixed designation D 4751; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.2 atmosphere for testing geosynthetics, n—air main-
tained at a relative humidity between 50 to 70 % and a
1.1 This test method covers the determination the apparent
temperature of 21 6 2°C (70 6 4°F).
opening size (AOS) of a geotextile by sieving glass beads
3.1.3 Discussion—The laboratory conditions are very im-
through a geotextile.
portant to the AOS test. For example, excessive humidity
1.2 This test method shows the values in both SI units and
(above 70 %) can cause beads to stick together; while too low
inch-pound units. SI units is the technically correct name for
a relative humidity (below 50 %) can result in an increase in
thesystemofmetricunitsknownastheInternationalSystemof
static electricity.
Units. Inch-pound units is the technically correct name for the
3.1.4 geotechnics, n—the application of scientific methods
customary units used in the United States. The values in
and engineering principles to the acquisition, interpretation,
inch-pound units are provided for information only.
and use of knowledge of materials of the earth’s crust to the
1.3 This standard does not purport to address all of the
solution of engineering problems.
safety concerns, if any, associated with its use. It is the
3.1.5 Discussion—Geotechnics embraces the fields of soil
responsibility of the user of this standard to establish appro-
mechanics, rock mechanics, and many of the engineering
priate safety and health practices and determine the applica-
aspects of geology, geophysics, hydrology, and related sci-
bility of regulatory limitations prior to use.
ences.
2. Referenced Documents
3.1.6 geotextile, n—any permeable textile material used
with foundation, soil, rock, earth, or any other geotechnical
2.1 ASTM Standards:
engineering related material as an integral part of a man-made
C 136 Test Method for Sieve Analysis of Fine and Coarse
project, structure, or system.
Aggregates
3.1.7 For the definitions of the other terms relating to
D 123 Terminology Relating to Textiles
geotextiles, refer to Terminology D 4439.
D 1776 Practice for Conditioning Textiles for Testing
3.2 For the definitions of the other terms relating to textiles,
D 4238 Test Method for Electrostatic Propensity of Tex-
refer to Terminology D 123.
tiles
D 4354 Practice for Sampling of Geosynthetics for Testing
4. Summary of Test Method
D 4439 Terminology for Geotextiles
4.1 A geotextile specimen is placed in a sieve frame, and
E 11 Specification for Wire-Cloth Sieves for Testing Pur-
5 sized glass beads are placed on the geotextile surface. The
poses
geotextile and frame are shaken laterally so that the jarring
3. Terminology motion will induce the beads to pass through the test specimen.
The procedure is repeated on the same specimen with various
3.1 Definitions:
size glass beads until its apparent opening size has been
3.1.1 apparent opening size (AOS), O , n—for a geotex-
determined.
tile, a property that indicates the approximate largest particle
that would effectively pass through the geotextile.
5. Significance and Use
5.1 Using a geotextile as a medium to retain soil particles
This test method is under the jurisdiction of ASTM Committee D-35 on
necessitatescompatibilitybetweenitandtheadjacentsoil.This
Geosynthetics and is the direct responsibility of Subcommittee D35.03 on Perme-
test method is used to indicate the apparent opening size in a
ability and Filtration.
geotextile, which reflects the approximate largest opening
Current edition approved Dec. 10, 1999. Published February 2000. Originally
published as D 4751 – 93. Last previous version D 4751 – 99.
dimension available for soil to pass through.
Annual Book of ASTM Standards, Vol 04.02.
Annual Book of ASTM Standards, Vol 07.01.
Annual Book of ASTM Standards, Vol 04.13.
Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4751–99a
TABLE 1 Glass Bead Sizes
5.2 Test Method D 4751 for the determination of opening
size of geotextiles is acceptable for testing of commercial Bead Size Range
A
shipments of geotextiles. Current estimates of precision, be-
Passing Retained Bead Size Designation
tween laboratories, are being established.
Sieve Sieve Sieve
mm mm mm
B B
5.2.1 In case of a dispute arising from differences in Number Number Number
reported test results when using Test Method D 4751 for
2.0 101.70 121.7 12
1.4 14 1.18 16 1.18 16
acceptance testing of commercial shipments, the purchaser and
1.00 18 0.850 20 0.850 20
the supplier should conduct comparative tests to determine if
0.710 25 0.600 30 0.600 30
there is a statistical bias between their laboratories. Competent
0.500 35 0.425 40 0.425 40
0.355 45 0.300 50 0.300 50
statistical assistance is recommended for the investigation of
0.250 60 0.212 70 0.212 70
bias.As a minimum, the two parties should take a group of test
0.180 80 0.150 100 0.150 100
specimens that are homogeneous as possible and that are from
0.125 120 0.106 140 0.106 140
0.090 170 0.075 200 0.075 200
a lot of material of the type in question. The test specimens
A
The designated bead size is the “retained on” size of the sieve pair used to size
should then be randomly assigned in equal numbers to each
the beads. For example, beads designated No. 40 are beads that pass the No. 35
laboratory for testing. The average results from the two
sieve and are retained on the No. 40 sieve. These beads are typically sold as
laboratories should be compared using Students t-test for
35-40 beads.
B
See Specification E 11.
unpaireddataandanacceptableprobabilitylevelchosenbythe
two parties before the testing is begun. If a bias is found, either
its cause must be found and corrected or the purchaser and the
geotextile. Commercially available devices or anti-static
supplier must agree to interpret future test results in the light of
sprays are acceptable.
the known bias.
6.6 Pan, for collecting sieved beads.
6. Apparatus
7. Sampling
6.1 Mechanical Sieve Shaker—A mechanical sieve shaker,
7.1 Lot Sample—For routine quality control testing, divide
which imparts lateral and vertical motion to the sieve, causing
the product into lots and take the lot sample as directed in
the particles thereon to bounce and turn so as to present
Practice D 4354, Section 7 Procedure B Sampling for Quality
different orientations to the sieving surface, should be used.
Assurance Testing. For Specification Conformance testing,
The sieve shaker should be a constant frequency device
sample as directed in Practice D 4354, Section 6 Procedure
utilizing a tapping arm to impart the proper motion to the glass
A—Sampling for Specification Conformance.
beads.
7.2 Laboratory Sample—As a laboratory sample for accep-
NOTE 1—Care should be given to the cork or rubber contact point on
tancetesting,takeafullwidthswatch1-m(1-yd)longfromthe
shakers when the vertical motion comes from an arm striking the cork or
end of each roll of fabric in the lot sample, after first discarding
rubber. Excessive wear on the cork or rubber could affect the motion
a minimum of1m(1yd)of fabric from the very outside of the
imparted to the glass beads and, therefore, the test result.
roll.
6.2 Pan, Cover, and 200-mm (8-in.) Diameter Sieves.
7.3 Test Specimens—Cut five specimens from each swatch
6.3 Spherical Glass Beads, in size fractions in accordance
inthelaboratorysamplewitheachspecimenbeingcuttofitthe
withTable 1. It is only necessary to have on hand the bead size
appropriate sieve pan. Cut the specimens from a single swatch
fractions necessary for the range of geotextiles for which
spaced along a diagonal line on the swatch.
testing is anticipated. The sizing of all beads shall be verified
prior to each use by sieving on the pairs of sieves shown in
8. Specimen Preparation
Table 1. Prepare at least 50 g of each size fraction to be used
8.1 Weigh the specimens and then submerge them in dis-
prior to beginning the test. Bead sizes to be used in this test
tilledwaterfor1hatthestandardatmospherefortesting.Bring
method are shown in Table 1.
the specimens to moisture equilibrium in the atmosphere for
6.4 Balance, having a capacity adequate for the mass of
testing geosynthetics. Equilibrium is considered to have been
samples anticipated and accurate to 60.05 g.
reached when the change in the mass of the specimen in
6.5 Static Elimination, to prevent the accumulation of static
successive weighings made at intervals of not less than 2 h
electricity when the beads are shaken on the surface of
does not exceed 0.1 g.
Asieve shaker of this type is available fromW. S.Tyler, Inc., 8200Tyler Blvd.,
Mentor, OH 44060. Static Eliminators available from Staticmaster Ionizing Units, Model #2U500,
Glass beads available from Cataphote Division, F
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