1、Designation: D 4751 04Standard Test Method forDetermining Apparent Opening Size of a Geotextile1This standard is issued under the fixed designation D 4751; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、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.1. Scope1.1 This test method covers the determination the appar
3、entopening size (AOS) of a geotextile by sieving glass beadsthrough a geotextile.1.2 This test method shows the values in both SI units andinch-pound units. SI units is the technically correct name forthe system of metric units known as the International System ofUnits. Inch-pound units is the techn
4、ically correct name for thecustomary units used in the United States. The values ininch-pound units are provided for information only.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 this standard to esta
5、blish appro-priate safety and health practices and determine the applica-bility of regulatory requirements prior to use.2. Referenced Documents2.1 ASTM Standards:2C 136 Test Method for Sieve Analysis of Fine and CoarseAggregatesD 123 Terminology Relating to TextilesD 1776 Practice for Conditioning T
6、extiles for TestingD 4238 Test Method for Electrostatic Propensity of TextilesD 4354 Practice for Sampling of Geosynthetics for TestingD 4439 Terminology for GeotextilesE11 Specification for Wire-Cloth Sieves for Testing Pur-poses3. Terminology3.1 Definitions:3.1.1 apparent opening size (AOS), O95,
7、nfor a geotex-tile, a property that indicates the approximate largest particlethat would effectively pass through the geotextile.3.1.2 atmosphere for testing geosynthetics, nair main-tained at a relative humidity between 50 to 70 % and atemperature of 21 6 2C (70 6 4F).3.1.3 DiscussionThe laboratory
8、 conditions are very im-portant to the AOS test. For example, excessive humidity(above 70 %) can cause beads to stick together; while too lowa relative humidity (below 50 %) can result in an increase instatic electricity.3.1.4 geotechnics, nthe application of scientific methodsand engineering princi
9、ples to the acquisition, interpretation,and use of knowledge of materials of the earths crust to thesolution of engineering problems.3.1.5 DiscussionGeotechnics embraces the fields of soilmechanics, rock mechanics, and many of the engineeringaspects of geology, geophysics, hydrology, and related sci
10、-ences.3.1.6 geotextile, nany permeable textile material usedwith foundation, soil, rock, earth, or any other geotechnicalengineering related material as an integral part of a man-madeproject, structure, or system.3.1.7 For the definitions of the other terms relating togeotextiles, refer to Terminol
11、ogy D 4439.3.2 For the definitions of the other terms relating to textiles,refer to Terminology D 123.4. Summary of Test Method4.1 A geotextile specimen is placed in a sieve frame, andsized glass beads are placed on the geotextile surface. Thegeotextile and frame are shaken laterally so that the jar
12、ringmotion will induce the beads to pass through the test specimen.The procedure is repeated on the same specimen with varioussize glass beads until its apparent opening size has beendetermined.5. Significance and Use5.1 Using a geotextile as a medium to retain soil particlesnecessitates compatibili
13、ty between it and the adjacent soil. Thistest method is used to indicate the apparent opening size in ageotextile, which reflects the approximate largest openingdimension available for soil to pass through.1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the d
14、irect responsibility of Subcommittee D35.03 on Perme-ability and Filtration.Current edition approved Nov. 1, 2004. Published December 2004. Originallyapproved in 1993. Last previous version approved in 2004 as D 4751 99a(2004).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orc
15、ontact 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 States.5.2 Test Method D 4
16、751 for the determination of openingsize of geotextiles is acceptable for testing of commercialshipments of geotextiles. Current estimates of precision, be-tween laboratories, are being established.5.2.1 In case of a dispute arising from differences inreported test results when using Test Method D 4
17、751 foracceptance testing of commercial shipments, the purchaser andthe supplier should conduct comparative tests to determine ifthere is a statistical bias between their laboratories. Competentstatistical assistance is recommended for the investigation ofbias. As a minimum, the two parties should t
18、ake a group of testspecimens that are homogeneous as possible and that are froma lot of material of the type in question. The test specimensshould then be randomly assigned in equal numbers to eachlaboratory for testing. The average results from the twolaboratories should be compared using Students
19、t-test forunpaired data and an acceptable probability level chosen by thetwo parties before the testing is begun. If a bias is found, eitherits cause must be found and corrected or the purchaser and thesupplier must agree to interpret future test results in the light ofthe known bias.6. Apparatus6.1
20、 Mechanical Sieve ShakerA mechanical sieve shaker,which imparts lateral and vertical motion to the sieve, causingthe particles thereon to bounce and turn so as to presentdifferent orientations to the sieving surface, should be used.The sieve shaker should be a constant frequency deviceutilizing a ta
21、pping arm to impart the proper motion to the glassbeads.3NOTE 1Care should be given to the cork or rubber contact point onshakers when the vertical motion comes from an arm striking the cork orrubber. Excessive wear on the cork or rubber could affect the motionimparted to the glass beads and, theref
22、ore, the test result.6.2 Pan, Cover, and 200-mm (8-in.) Diameter Sieves.6.3 Spherical Glass Beads,4in size fractions in accordancewith Table 1. It is only necessary to have on hand the bead sizefractions necessary for the range of geotextiles for whichtesting is anticipated. The sizing of all beads
23、shall be verifiedprior to each use by sieving on the pairs of sieves shown inTable 1. Prepare at least 50 g of each size fraction to be usedprior to beginning the test. Bead sizes to be used in this testmethod are shown in Table 1.6.4 Balance, having a capacity adequate for the mass ofsamples antici
24、pated and accurate to 60.05 g.6.5 Static Elimination, to prevent the accumulation of staticelectricity when the beads are shaken on the surface ofgeotextile.5Commercially available devices or anti-staticsprays are acceptable.6.6 Pan, for collecting sieved beads.7. Sampling7.1 Lot SampleFor routine q
25、uality control testing, dividethe product into lots and take the lot sample as directed inPractice D 4354, Section 7 Procedure B Sampling for QualityAssurance Testing. For Specification Conformance testing,sample as directed in Practice D 4354, Section 6 ProcedureASampling for Specification Conforma
26、nce.7.2 Laboratory SampleAs a laboratory sample for accep-tance testing, take a full width swatch 1-m (1-yd) long from theend of each roll of fabric in the lot sample, after first discardinga minimum of1m(1yd)offabric from the very outside of theroll.7.3 Test SpecimensCut five specimens from each sw
27、atchin the laboratory sample with each specimen being cut to fit theappropriate sieve pan. Cut the specimens from a single swatchspaced along a diagonal line on the swatch.8. Specimen Preparation8.1 Weigh the specimens and then submerge them in dis-tilled water for1hatthestandard atmosphere for test
28、ing. Bringthe specimens to moisture equilibrium in the atmosphere fortesting geosynthetics. Equilibrium is considered to have beenreached when the change in the mass of the specimen insuccessive weighings made at intervals of not less than 2 hdoes not exceed 0.1 g.NOTE 2It is recognized that in prac
29、tice, geosynthetic materials arefrequently not weighed to determine when moisture equilibrium has beenreached. While such a method cannot be accepted in cases of dispute, itmay be sufficient in routine testing to expose the material to the standardatmosphere for testing geosynthetics for a reasonabl
30、e period of timebefore the specimens are tested. A time of at least 24 h has been foundacceptable in most cases. However, certain fibers may contain moremoisture upon receipt than after conditioning. When this is known, a3Asieve shaker of this type is available from W. S. Tyler, Inc., 8200 Tyler Blv
31、d.,Mentor, OH 44060.4Glass beads available from Cataphote Division, Ferro Corporation, P.O. Box2369, Jackson, MS 39205, or Potters Industries, Inc., 377-T, Route 17, HasbrouckHeights, NJ 07604, or beads of equal quality have been found satisfactory for thispurpose.5Static Eliminators available from
32、Staticmaster Ionizing Units, Model #2U500,Nuclear Products Co., P.O. Box 5178, El Monte, CA 91733, or Western StaticEliminators Co., 215-219 S. Western Avenue, Chicago, IL 60612, have been foundsatisfactory for this purpose. For other availability addresses, see Footnote 7 of TestMethod D 4238.TABLE
33、 1 Glass Bead SizesBead Size RangePassing Retained Bead Size DesignationAmmSieveNumberBmmSieveNumberBmmSieveNumber2.0 101.70 121.7 121.4 14 1.18 16 1.18 161.00 18 0.850 20 0.850 200.710 25 0.600 30 0.600 300.500 35 0.425 40 0.425 400.355 45 0.300 50 0.300 500.250 60 0.212 70 0.212 700.180 80 0.150 1
34、00 0.150 1000.125 120 0.106 140 0.106 1400.090 170 0.075 200 0.075 200AThe designated bead size is the “retained on” size of the sieve pair used to sizethe beads. For example, beads designated No. 40 are beads that pass the No. 35sieve and are retained on the No. 40 sieve. These beads are typically
35、sold as35-40 beads.BSee Specification E11.D4751042preconditioning cycle, as described in Practice D 1776, may be agreedupon by the contractual parties.9. Procedure9.1 Run the test at the atmosphere for testing geotextiles insuch a manner that static electricity is prevented from affectingtest result
36、s. If standard atmosphere cannot be maintained andstatic electricity is noticed, two methods are available that willprevent static electricity:9.1.1 Install static eliminating devices equally spaced aboutthe circumference of sieve and one on center of cover, or9.1.2 Apply commercially available anti
37、-static spray uni-formly to the geotextile.9.2 Secure the geotextile in such a way that it is taut,without wrinkles or bulges. The geotextile must not bestretched or deformed such that it changes or distorts theopenings in the fabric. Two systems may be used to secure thegeotextiles sample:9.2.1 Wed
38、ge between two sieve frames.9.2.2 Secure with hoop inside the sieve frame.9.3 Prior to use, sieve the glass beads in the laboratory toverify size of beads.NOTE 3All size glass beads are sieved through a single specimen ofgeotextile unless the geotextile has an average thickness equal to orgreater th
39、an 2.3 mm (0.091 in.). A geotextile of this thickness or greater(especially nonwovens) may trap beads within the layers of the fabric,which may pass through the specimen when testing with a different beadsize, thus creating an error in the test results. In the case of the thickergeotextiles, a diffe
40、rent specimen may be used for each bead size; however,it should be noted in the report that different specimens were used.9.4 Start with the smallest diameter glass beads that will betested. Place 50 g of one size glass beads on the center of thegeotextile.9.5 Place cover and pan on sieve frame and
41、place in shaker.Shake sieves for 10 min.9.6 Place the glass beads still on the surface of the specimenin a pan and weigh. Include beads that fall off as a result ofturning the specimen over and tapping the rims of the sieves.NOTE 4This step provides information concerning the amount ofglass beads tr
42、apped within the geotextile and the amount of any beads lostduring testing.9.7 Weigh the glass beads that pass through the specimen,and record data. (See Fig. 1 for a sample worksheet which canbe used to record the desired data).FIG. 1 Sample WorksheetD47510439.8 Repeat 9.3 through 9.7 using the nex
43、t larger bead sizefraction. Repeat the trial using succeedingly larger bead sizefractions until the weight of beads passing through the speci-men is 5 % or less. Perform the trials such that the percentpassing decreases from a value greater than 5 % to a value lessthan or equal to 5 %.9.9 Repeat 9.2
44、 to 9.8 for all five specimens.10. Calculation10.1 For each size of beads tested with each specimen,compute to the nearest percent the beads passing through thespecimen using Eq 1:B 5 100 P/T (1)where:B = beads passing through specimen, %,P = mass of glass beads in the pan, g, andT = total mass of g
45、lass beads used, g.10.2 Record calculations and percent beads passing (seeFig. 1).10.3 Assign the AOS for each specimen as the size desig-nation in millimetres (see 6.3) of the beads of which 5 % or lesspass.10.4 Determine the AOS for the test by averaging the AOSvalues of the five specimens.11. Plo
46、tting11.1 It is often desirable to determine the AOS value byplotting the percentage of beads passing the specimen versusthe bead size for each of the bead sizes used for each specimen.When plotting is desirable, proceed as follows:11.1.1 For each specimen, plot the values of Percent Passing(Ordinat
47、e) versus Bead Size, mm (Abscissa) on semi-log graph(see Fig. 2). Draw a straight line connecting the two data pointsrepresenting the bead sizes that are immediately on either sideof the 5 % passing ordinate. The particle size in mm (abscissa)at the intersection of the straight line plotted and the
48、5 %passing ordinate is the AOS of the specimen in mm, that is, thetheoretical bead size that would result in exactly 5 % passingthe specimen.11.1.2 Determine the sample AOS, in mm, by averaging thefive AOS values obtained by the graphic interpolation in11.1.1.11.1.3 Determine the sample AOS, express
49、ed in terms ofsieve number, as the number of the U.S. Sieve (see the sieveFIG. 2 Semilog PlotD4751044number column under Bead Size Designation of Table 1)having nominal opening, in millimetres, equal to or next largerthan the AOS, in millimetres, obtained in 11.1.1.12. Report12.1 Report that the specimens were tested as directed inTest Method D 4751. Describe the material or product sampledand the method of sampling used.12.2 Report the following information:12.2.1 Results in written form indicating the bead sizeranges used in millimetres.12.2.2 If requested, plots
