1、Designation: D4884 091Standard Test Method forStrength of Sewn or Thermally Bonded Seams ofGeotextiles1This standard is issued under the fixed designation D4884; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEThis Test Method was changed editorially in 2012. The affected portion is Equation 1.1. Scope1.1 This test method covers the seam stre
3、ngth of geotextiles.The primary distinction of this test method for evaluating seamstrength is the width of the specimen. This is in contrast to themore narrow specimen width used in the tensile grab strengthtest discussed in Test Method D1683.1.2 This test method will provide data to indicate the s
4、eamstrength that can be achieved for each particular geotextile andseam assembly construction.1.3 The values stated in SI units are to be regarded asstandard. The inch-pound units given in parentheses areprovided for information only.1.4 This standard does not purport to address all of thesafety con
5、cerns, if any, associated with its use. It 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:2D76 Specification for Tensile Testing
6、Machines for TextilesD123 Terminology Relating to TextilesD1683 Test Method for Failure in Sewn Seams of WovenApparel FabricsD1776 Practice for Conditioning and Testing TextilesD1777 Test Method for Thickness of Textile MaterialsD4439 Terminology for GeosyntheticsD4595 Test Method for Tensile Proper
7、ties of Geotextiles bythe Wide-Width Strip MethodE178 Practice for Dealing With Outlying ObservationsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 Federal Standard:Fed. Std. No. 751a Stitches, Seams, and Stitchings33. Terminology3.1 Definitions:3
8、.1.1 cross-machine directionthe direction in the plane ofthe geotextile perpendicular to the direction of manufacture.3.1.2 geotextile, na permeable geosynthetic comprisedsolely of textiles.3.1.3 linear density, nmass per unit length; the quotientobtained by dividing the mass of a fiber or yarn by i
9、ts length.3.1.4 machine directionthe direction in the plane of thegeotextile parallel to the direction of manufacture.3.1.5 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, and for thermallybonde
10、d seams bounded by the edge of the geotextile and thefurthest seam edge.3.1.5.1 DiscussionIn geotextiles, the distance from theselvage or turned edge of the geotextile to the edge of the seam.3.1.6 seam assembly, nthe unit obtained by joining geo-textile with a seam, including details such as geotex
11、tiledirection(s), seam allowance, seam width, seam type, speed,and if sewnsewing threads used and number of stitches perunit length, needle type and size, and so forth.3.1.7 seam effciency, nthe ratio expressed as a percentageof seam strength to geotextile strength.3.1.8 seam design engineering, nth
12、e 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,specific seam bonding temperature, and a specific seam speedand pressure to achieve the required s
13、eam strength of athermally bonded seam.1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechani-cal Properties.Current edition approved June 1, 2009. Published April 2012. Originallyap-proved in 1989. Last pr
14、evious edition approved in 2009 as D4884 09. DOI:10.1520/D4884-09E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM
15、website.3Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.9 seam interaction, nthe result of combini
16、ng specifictextile, a specific stitch type, and a specific seam type for asewn seam and the result of combining specific textile, aspecific seam width, a specific seam speed, and appliedpressure for a thermally bonded seam.3.1.10 seam type, nin sewn geotextiles, an alphanumericdesignation relating t
17、o the essential characteristics of geotextilepositioning and rows of stitching in a specific sewn geotextileseam (see Fed. Std. No. 751a).3.1.10.1 DiscussionThe first two letters of the designationshow seam type; the third and subsequent letter specify aparticular mating alignment; the number design
18、ation indicatesthe number of rows of stitches.3.1.11 seam weld, nthe process by which a seam isformed through the thermal bonding of separate layers ofgeotextile.3.1.12 selvage, nthe woven edge portion of a geotextileparallel to the machine direction.3.1.12.1 DiscussionThe edge of a nonwoven geotext
19、ilecannot be easily distinguished to determine either the machineor cross-machine direction.3.1.13 sewing thread, na flexible, small diameter yarn orstrand, usually treated with a surface coating, or lubricant, orboth, intended to be used to stitch one or more pieces ofmaterial or an object to a mat
20、erial.3.1.14 sewn seam, nin sewn geotextiles, a series ofstitches joining two or more separate plies of a material ormaterials of planar structure such as a textile geotextile.3.1.15 sewn seam strength, n for geotextiles, the maxi-mum resistance, measured in kilonewtons per metre, of thejunction for
21、med by stitching together two or more planarstructures.3.1.16 stitch, nthe repeated unit formed by the sewingthread in the production of seams in a sewn geotextile (see Fed.Std. No. 751a).3.1.17 tensile strength, nthe maximum resistance of ma-terial to deformation in a tensile test carried to ruptur
22、e; that is,the breaking load, or force per unit cross-sectional area of theunstrained specimen.3.1.18 thermally bonded seam, n in geotextiles, a seammade by the application of thermal energy.3.1.19 thermally bonded seam strength, nfor geotextiles,the maximum shear resistance, measured in kilonewtons
23、 permetre, of the junction formed by thermally bonding togethertwo or more planar structures.3.1.20 For definitions of other terms relating to textiles,refer to Terminology D123. For definitions of other termsrelating to geotextiles, refer to Terminology D4439.4. Summary of Test Method4.1 Aseam, 200
24、 mm (8 in.) wide is gripped across the entirewidth in the clamps of a tensile testing machine, operated at aprescribed 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,
25、narrow geotextilespecimens demonstrate the tendency to contract (neck down) inthe gage area when under stress. The wider width specimenwill minimize this phenomenon in seams during strengthtesting. The results achieved in this test method can moreaccurately correlate to the seam strength values anti
26、cipated inthe field.5.2 This test method can be used to measure the seamstrength of geotextiles, and may also be used for acceptancetesting of commercial shipments of geotextiles. When strengthis not necessarily a design consideration of seam interaction, analternate method for determining the seam
27、strength, such asTest Method D1683, may be used depending on the specifica-tion requirements. Because current information about labora-tory precision is incomplete, comparative tests, as described in5.2.1, may be advisable.5.2.1 In case of a dispute arising from differences inreported test results w
28、hen using this test method for acceptancetesting of commercial shipments, the purchaser and the sup-plier should perform comparative tests to determine if there isa statistical bias between their laboratories. Competent statis-tical assistance is recommended for the investigation of bias.As a minimu
29、m, the two parties should take a group of testspecimens from the same lot of geotextile, that utilize a likemethod of seam assembly to achieve seam interaction. Thespecimens should then be randomly assigned in equal numberto each laboratory for testing. If a bias is found, either its causemust be de
30、termined and corrected, or the purchaser and thesupplier must agree to interpret future test results in light of theknown bias.5.3 Although other methods of determining seam strengthare available, this test method, that measures wide specimens,will more accurately correlate to the anticipated perfor
31、mance inthe field.5.4 This test method can be used to help determine seamdesign engineering for the geotextiles being evaluated.6. Apparatus6.1 Tensile Testing Machine, must be of the constant-rate-of-extension (CRE) type, conforming to Specification D76 andequipped with a recorder having an adequat
32、e pen response orinterfaced computer to record the load elongation curve. Themachine must be set to a rate of extension of 10 6 3 %/min.6.2 ClampsThe clamps shall be wide enough to grip theentire width of the specimen and have the appropriate clampingpower to hold the test specimen in place without
33、crushing(damaging) the machine direction and cross-machine directionyarns.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 bearingface measuring wider than the width of the specimen, 200 mm(
34、8 in.) and a minimum of 50 mm (2 in.) in length, 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 Sample Divide the materialinto lots and take a lot sample as de
35、scribed in an applicablematerial specification, or as agreed upon between the purchaserD4884 0912and 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 the purchaser
36、 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.7.2 Laboratory SamplesAt a laboratory sample, cut aminimum of two swatches of geotextile
37、from each of the lotunits selected for testing. The swatches must be a minimum of2000 mm (79 in.) in length and a minimum of 300 mm (12 in.)in width. The lengthwise direction of these swatches must becut from opposite ends and opposite sides of the lot samplerolls and should be parallel to the direc
38、tion in which the seamwill be made.7.2.1 When seams are made in both the machine andcross-machine direction, it is suggested that some type ofspecial color identification marking be used to distinguish onefrom the other.7.2.2 These swatches are then joined using the best seamengineering techniques d
39、etermined 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 and conditioned tests.7.3 Test Specimens:7.3.1 Number of SpecimensIn the absence of an appli-cable specification or prior agreement between the purchas
40、erand the supplier, prepare at least six test specimens from thelaboratory samples.7.3.2 Test Specimen SizePrepare test specimens from thelaboratory sample. Each specimen should be approximately250 mm (10 in.) wide with a stitch line in the center for sewnseams or approximately 200 mm (8 in.) wide w
41、ith the seamweld in the center for thermally bonded seams running parallelto either the machine or cross-machine directions as shown inFig. 1(a) for sewn seams or Fig. 1(b) for thermally bondedseams.7.3.2.1 Cut this wider specimen for sewn seams as shown inFig. 1(a) to achieve a final test specimen
42、width of 200 mm (8in.). When removing the shaded area from a specimen asshown in Fig. 1(a), the angles between the 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
43、 loss of the integrity of the seam, and thus to anunderestimation of the seam strength. For these patterns, somemeans 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 d
44、amaging the sewing thread, in order to have at least200 mm of intact seam centered in the axis of the specimen.Both upper and lower threads of the seam shall then be tiedtogether to avoid any further modification to the structure ofthe stitch during the test.8. Sampling of Field Seams and Factory Se
45、ams8.1 The evaluation of field seams and factory seams will bemade by taking samples at the stipulated intervals 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 t
46、hat all seam samples can be taken from alternate sides of panelsat or near the end of the rolls.8.2 The lengthwise 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 bot
47、hwet and conditioned tests to be performed.FIG. 1 (a) Test Specimen Preparation for Sewn Seam (Front View)FIG. 1 (b) Test Specimen Preparation for Thermally Bonded Seam(Front View) (continued)TABLE 1 Seam Quality Control Sampling RequirementsTotal Length of FieldASeams for Project, m (yd)Sample Inte
48、rvalBRequirements, m (yd)Up to 10 000 (Up to 11 000) 1000 (1100)10 001 to 150 000 (11 000 to 165 000) 1500 (1666)150 000 and up (165 000 and up) 2000 (2200)ATotal length of field seams for project is the sum of all machine direction andcross-machine direction seams required to effect installation of
49、 geotextile(s).BSamples will be taken at stipulated intervals along the total length of the fieldseams. The number of such intervals will be rounded to the next higher wholenumber.D4884 09138.3 Prepare test specimens as specified in Section 7, 7.3.2,and, if sewn, 7.3.2.1.9. Conditioning9.1 Bring the specimens to moisture equilibrium in theatmosphere for testing geotextiles. Equilibrium is considered tohave been reached when the increase in mass of the specimenin successive weighings made at intervals of not less than 2 hdoes not exceed 0.1 % of
