1、Designation: D4884/D4884M 14Standard Test Method forStrength of Sewn or Bonded Seams of Geotextiles1This standard is issued under the fixed designation D4884/D4884M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the seamstrength of geotextiles, using a wide specimen.1.2 The long term perfo
3、rmance of a seaming technique isnot addressed by this test method. This test method willprovide data to indicate the short term seam strength that canbe achieved for each particular geotextile and seam assemblyconstruction. To assess the long term performance of a seamingtechnique, it is possible to
4、 use Practice D6389, using this testmethod to determine the anticipated strength reduction in theinitial, short term wide-width tensile strength (Test MethodD4595) results.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach
5、system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is the
6、responsibility 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:2D76/D76M Specification for Tensile Testing Machines forTextilesD1776 Practice for Condi
7、tioning and Testing TextilesD1777 Test Method for Thickness of Textile MaterialsD4439 Terminology for GeosyntheticsD4595 Test Method for Tensile Properties of Geotextiles bythe Wide-Width Strip MethodD6389 Practice for Tests to Evaluate the Chemical Resis-tance of Geotextiles to LiquidsE178 Practice
8、 for Dealing With Outlying ObservationsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 Federal Standard:3Fed. Std. No. 751a Stitches, Seams, and Stitchings3. Terminology3.1 Definitions:3.1.1 adhered seam, nin geotextiles, a seam made by theapplicat
9、ion of an adhesive.3.1.2 cross-machine directionthe direction in the plane ofthe geotextile perpendicular to the direction of manufacture.3.1.3 geotextile, na permeable geosynthetic comprisedsolely of textiles.3.1.4 linear density, nmass per unit length; the quotientobtained by dividing the mass of
10、a fiber or yarn by its length.3.1.5 machine directionthe direction in the plane of thegeotextile parallel to the direction of manufacture.3.1.6 seam allowance, nthe width of geotextile used inmaking a seam assembly, for sewn seams bounded by the edgeof the geotextile and the furthest stitch line, an
11、d for thermallybonded seams bounded by the edge of the geotextile and thefurthest seam edge.3.1.6.1 DiscussionIn geotextiles, the distance from theselvage or turned edge of the geotextile to the edge of the seam.3.1.7 seam assembly, nthe unit obtained by joining geo-textile with a seam, including de
12、tails such as geotextiledirection(s), seam allowance, seam width, seam type, speed,and if sewnsewing threads used and number of stitches perunit length, needle type and size, and if adhered adhesiveused, amount of adhesive in weight per unit area, overlapdimension and one or both sides with adhesive
13、 applied and soforth.3.1.8 seam design engineering, nthe procedures used toselect a specific thread, a specific stitch type, and a specificseam type to achieve the required seam strength of a sewnseam and the procedures used to select a specific seam width,1This test method is under the jurisdiction
14、 of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechani-cal Properties.Current edition approved Jan. 15, 2014. Published February 2014. Originallyapproved in 1989. Last previous edition approved in 2013 as D4884 13. DOI:10.1520/D4884_D4884M-14.2For r
15、eferenced ASTM standards, visit the ASTM website, 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.3Available from DLA Document Services, Building 4/D, 700 Robbins Av
16、e.,Philadelphia, PA 19111-5094, http:/quicksearch.dla.mil.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1specific seam bonding temperature, a specific seam speed andpressure to achieve the required seam strength of a thermallybonded
17、seam and the type and amount of adhesive, overlapdimension and whether the adhesive was applied to one or bothsides of the overlap to achieve the required seam strength of anadhered seam.3.1.9 seam effciency, nthe ratio expressed as a percentageof seam strength to geotextile strength.3.1.10 seam int
18、eraction, nthe result of combining specifictextile, a specific stitch type, and a specific seam type for asewn seam, the result of combining specific textile, a specificseam width, a specific seam speed, and applied pressure for athermally bonded seam and the type and amount of adhesive,overlap dime
19、nsion and whether the adhesive was applied toone or both sides of the overlap to achieve the required seamstrength of an adhered seam.3.1.11 seam strength, nfor geotextiles, the maximumresistance, measured in kilonewtons per metre, of the junctionformed by stitching together two or more planar struc
20、tures.3.1.12 seam type, nin sewn geotextiles, an alphanumericdesignation relating to the essential characteristics of geotextilepositioning and rows of stitching in a specific sewn geotextileseam (see Fed. Std. No. 751a).3.1.12.1 DiscussionThe first two letters of the designationshow seam type; the
21、third and subsequent letter specify aparticular mating alignment; the number designation indicatesthe number of rows of stitches.3.1.13 seam weld, nthe process by which a seam isformed through the thermal bonding of separate layers ofgeotextile.3.1.14 selvage, nthe woven edge portion of a geotextile
22、parallel to the machine direction.3.1.14.1 DiscussionThe edge of a nonwoven geotextilecannot be easily distinguished to determine either the machineor cross-machine direction.3.1.15 sewing thread, na flexible, small diameter yarn orstrand, usually treated with a surface coating, or lubricant, orboth
23、, intended to be used to stitch one or more pieces ofmaterial or an object to a material.3.1.16 sewn seam, nin sewn geotextiles,aseriesofstitches joining two or more separate plies of a material ormaterials of planar structure such as a textile geotextile.3.1.17 stitch, nthe repeated unit formed by
24、the sewingthread in the production of seams in a sewn geotextile (see Fed.Std. No. 751a).3.1.18 tensile strength, nin geotextile seam evaluation, theforce per unit width measured per Test Method D4595 on theweakest of the two geotextile panels seamed together.3.1.19 thermally bonded seam, nin geotex
25、tiles, a seammade by the application of thermal energy.3.1.20 For definitions of other terms relating to geotextiles,refer to Terminology D4439.4. Summary of Test Method4.1 Aseam, 200 mm 8 in. wide is gripped across the entirewidth in the clamps of a tensile testing machine, operated at aprescribed
26、rate of extension, applying a longitudinal (perpen-dicular) force to the specimen until the seam or geotextileruptures.5. Significance and Use5.1 As explained in Test Method D4595, narrow geotextilespecimens demonstrate the tendency to contract (neck down) inthe gage area when under stress. The wide
27、r width specimenwill minimize this phenomenon in seams during strengthtesting. The results achieved in this test method can moreaccurately correlate to the seam strength values anticipated inthe field.5.2 This test method can be used to measure the seamstrength of geotextiles, and may also be used f
28、or acceptancetesting of commercial shipments of geotextiles.5.3 This test method can be used to help determine seamdesign engineering for the geotextiles being evaluated.5.4 This test method is not intended to address long termperformance of a seam nor any of its components such as thethread or the
29、adhesive. However, it can be used as an indexvalue to monitor the behavior of a seam exposed to anyparticular exposure, in example as part of an effort to assess itslong term performance.6. Apparatus6.1 Tensile Testing Machine, must be of the constant-rate-of-extension (CRE) type, conforming to Spec
30、ification D76/D76M and equipped with a recorder having an adequate penresponse or interfaced computer to record the load elongationcurve. The machine must be set to a rate of extension of 10 63 %/min.6.2 ClampsThe clamps shall be wide enough to grip theentire width of the specimen and have the appro
31、priate clampingpower to hold the test specimen in place without crushing(damaging) the geotextile.6.2.1 Caution must be taken to ensure that the type of clampused is adequate for the seam strength being measured.6.3 Size of Jaw FacesEach clamp shall have a clampingface wider than the width of the sp
32、ecimen, typically 225 mm8.86 in. or larger, and a minimum of 50 mm 2 in. in thedirection of the applied force. The size of jaw faces does notapply if roller clamps are used.7. Sampling for Acceptance Testing and Number ofSpecimens7.1 Division into Lots and Lot SampleDivide the materialinto lots and
33、take a lot sample as described in an applicablematerial specification, or as agreed upon between the purchaserand the supplier. In the absence of an applicable materialspecification or prior agreement between the purchaser and thesupplier, sampling and testing intervals should be agreed uponbetween
34、the purchaser and the supplier.7.1.1 When the installation project requires that seams aremade in both the machine and cross-machine directions, thenumber of samples and the subsequent specimens will increaseproportionately.D4884/D4884M 1427.2 Laboratory SamplesAt a laboratory sample, cut aminimum o
35、f two swatches of geotextile from each of the lotunits selected for testing. The swatches must be long and largeenough to permit seaming and selection of representativesections of seams for specimen preparation, such as, a mini-mum of 2000 mm 79 in. in length and a minimum of 300 mm12 in. in width.
36、The lengthwise direction of these swatchesmust be cut from opposite ends and opposite sides of the lotsample rolls and should be parallel to the direction in which theseam will be made.7.2.1 When seams are made in both the machine andcross-machine direction, it is suggested that some type ofspecial
37、color identification marking be used to distinguish onefrom the other.7.2.2 These swatches are then joined using the best seamengineering techniques determined by the purchaser and thesupplier to achieve seam interaction.7.2.3 It will be necessary to cut a sufficient number ofswatches for both wet a
38、nd conditioned tests.7.3 Test Specimens:7.3.1 Number of SpecimensIn the absence of an appli-cable specification or prior agreement between the purchaserand the supplier, prepare at least six test specimens from thelaboratory samples.7.3.2 Test Specimen SizePrepare test specimens from thelaboratory s
39、ample. Each specimen should be approximately250 mm 10 in. wide with a stitch line in the center for sewnseams or approximately 200 mm 68 in. wide with the seamweld in the center for thermally bonded or adhered seamsrunning parallel to either the machine or cross-machine direc-tions as shown in Fig.
40、1(a) for sewn seams, Fig. 1(b) forthermally bonded seams or Fig. 1(c) for adhered seams.7.3.2.1 Cut this wider specimen for sewn seams as shown inFig. 1(a) to achieve a final test specimen width of 200 mm 8in. When removing the shaded area from a specimen asshown in Fig. 1(a), the angles between the
41、 25-mm extensionswhich are parallel to the seam and that section of the specimenhaving a finished width of 200 mm is 90.7.3.2.2 For some seaming patterns, cutting the thread maylead to a loss of the integrity of the seam, and thus to anunderestimation of the seam strength. For these patterns, someme
42、ans shall be used to lock the thread in place, such as usingglue, or mechanically locking the thread on both ends of theseam by un-sewing the seam over a maximum length of 25mm, without damaging the sewing thread, in order to have atleast 200 mm of intact seam centered in the axis of thespecimen. Bo
43、th upper and lower threads of the seam shall thenbe tied together to avoid any further modification to thestructure of the stitch during the test.8. Sampling of Field Seams and Factory Seams8.1 The evaluation of field seams and factory seams will bemade by taking samples at the stipulated intervals
44、directed inTable 1 unless otherwise stated.NOTE 1To prevent the unnecessary waste of geotextile or impede theinstallation, it should be agreed upon between the supplier and thepurchaser that all seam samples can be taken from alternate sides of panelsat or near the end of the rolls.8.2 The lengthwis
45、e direction of these swatches should beparallel to the direction of the seam, either in the machine orcross-machine direction.8.2.1 It will be necessary to cut additional swatches for bothwet and conditioned tests to be performed.FIG. 1 (a) Test Specimen Preparation for Sewn Seam (Front View)FIG. 1
46、(b) Test Specimen Preparation for Thermally Bonded Seam(Front View) (continued)FIG. 1 (c) Test Specimen Preparation for Adhesive Bonded Seam(Front View) (continued)D4884/D4884M 1438.3 Prepare test specimens as specified in 7.3.2.9. Conditioning9.1 Bring the specimens to moisture equilibrium in theat
47、mosphere for testing geotextiles. Equilibrium is considered tohave been reached when the increase in mass of the specimenin successive weighing made at intervals of not less than 2 hdoes not exceed 0.1 % of the mass of the specimen. Unless thepurchaser and the supplier agree otherwise, bring the tes
48、tspecimens to moisture equilibrium starting with the conditionin which they were received.9.1.1 Certain fibers may exhibit slow moisture equalizationrates when received in a wet condition. When this is known,the purchaser and the supplier may agree to use a precondi-tioning cycle as specified in Pra
49、ctice D1776.NOTE 2It is recognized that, in practice, geotextile materials arefrequently not weighted to determine when moisture equilibrium has beenreached. While such a procedure cannot be accepted in cases of dispute,it may be sufficient in routine testing to expose the material to the standardatmosphere for testing for a reasonable period of time before thespecimens are tested. A time of at least 24 h has been found acceptable inmost cases.10. Wet Testing (optional)10.1 Wet field conditions require that one test should beper
