1、Designation: D 4884 96 (Reapproved 2003)Standard Test Method forStrength of Sewn or Thermally Bonded Seams ofGeotextiles1This standard is issued under the fixed designation D 4884; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the seam strength of geotextiles.The primary distinction of this test method for ev
3、aluating 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 D 1683.1.2 This test method will provide data to indicate the seamstrength that can be achieved for each particular geotextile andse
4、am 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 concerns, if any, associated with its use. It is theresponsibility of th
5、e 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:D 76 Specification for Tensile Testing Machines for Tex-tiles2D 123 Terminology Relating to Textiles2D 1683
6、Test Method for Failure in Sewn Seams of WovenFabrics2D 1776 Practice for Conditioning Textiles for Testing2D 1777 Method for Measuring Thickness of Textile Mate-rials2D 4354 Practice for Sampling of Geosynthetics for Testing3D 4439 Terminology for Geosynthetics3D 4595 Test Method for Tensile Proper
7、ties of Geotextilesby the Wide Width Strip Method3D 4632 Test Method for Grab Breaking Load and Elonga-tion of Geotextiles3E 178 Practice for Dealing with Outlying Observations4E 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of Test Methods42.2 Federal Standard:Fed.
8、Std. No. 751a Stitches, Seams, and Stitchings53. Terminology3.1 Definitions:3.1.1 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 u
9、nit length; the quotientobtained by dividing the mass of a fiber or yarn by its 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 t
10、he edgeof the geotextile and the furthest stitch line, and for thermallybonded 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
11、obtained by joining geo-textile with a seam, including details 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 so forth.3.1.7 seam effciency, nthe ratio expressed as a percent
12、ageof seam strength to geotextile strength.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,specific seam bonding
13、 temperature, and a specific seam speedand pressure to achieve the required seam strength of athermally bonded seam.3.1.9 seam interaction, nthe result of combining specifictextile, a specific stitch type, and a specific seam type for a1This test method is under the jurisdiction of ASTM Committee D3
14、5 onGeosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechani-cal Properties.Current edition approved Feb. 10, 1996. Published June 1996. Originallypublished as D 4884 89. Last previous edition D 4884 90.2Annual Book of ASTM Standards, Vol 07.01.3Annual Book of ASTM Standards,
15、 Vol 04.13.4Annual Book of ASTM Standards, Vol 14.02.5Available 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.s
16、ewn 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 to the essential characteristics of geotextilepositioning and rows of stitch
17、ing 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 designation indicatesthe number of rows of stitches.3.1.11 seam weld, nthe proces
18、s 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 geotextilecannot be easily distinguished to determine either the machineor cross-m
19、achine 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 material.3.1.14 sewn seam, nin sewn geotextiles, a series ofstitches joining t
20、wo 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 formed by stitching together two or more planarstructures.3.1.16 stitch, nthe
21、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 rupture; that is,the breaking load, or force per unit cross-sectional area of the
22、unstrained 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 permetre, of the junction formed by thermally bonding togethertwo or more
23、planar structures.3.1.20 For definitions of other terms relating to textiles,refer to Terminology D 123. For definitions of other termsrelating to geotextiles, refer to Terminology D 4439.4. Summary of Test Method4.1 A seam, 200 mm (8 in.) wide is gripped across the entirewidth in the clamps of a te
24、nsile 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 D 4595, narrow geotextilespecimens demonstrate the tendency to contract (neck d
25、own) 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 anticipated inthe field.5.2 This test method can be used to measure the sea
26、mstrength 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 strength, such asTest Method D 1683, may be used depending on the speci
27、fi-cation requirements. Because current information about labo-ratory precision is incomplete, comparative tests, as describedin 5.2.1, may be advisable.5.2.1 In case of a dispute arising from differences inreported test results when using this test method for acceptancetesting of commercial shipmen
28、ts, 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 minimum, the two parties should take a group of testspecimens from the same
29、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 determined and corrected, or the purchaser and thesupplier must agree to
30、 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 performance inthe field.5.4 This test method can be used to help determine s
31、eamdesign 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 D 76 andequipped with a recorder having an adequate pen response orinterfaced computer to record the load elongation cu
32、rve. 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 crushing(damaging) the machine direction and cross-machine directiony
33、arns.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(8 in.) and a minimum of 50 mm (2 in.) in length, in thedirection of t
34、he 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 described in an applicablematerial specification, or as agreed upon bet
35、ween the purchaserand the supplier. In the absence of an applicable materialspecification or prior agreement between the purchaser and theD 4884 96 (2003)2supplier, sampling and testing intervals should be agreed uponbetween the purchaser and the supplier.7.1.1 When the installation project requires
36、 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 from each of the lotunits selected for testing. The swatches m
37、ust 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 direction in which the seamwill be made.7.2.1 When seams are made i
38、n 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 determined by the purchaser and thesupplier to achieve seam int
39、eraction.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 purchaserand the supplier, prepare at least six test specimens from t
40、helaboratory 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 with the seamweld in the center for thermally bonded seams runn
41、ing 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 width of 200 mm (8in.). When removing the shaded area from a s
42、pecimen 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 90.8. Sampling of Field Seams and Factory Seams8.1 The evaluation of field seams and factory seams will bemade by taking samples at
43、 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 that all seam samples can be taken from alternate sides of panelsat or near the end of t
44、he 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 bothwet and conditioned tests to be performed.8.3 Prepare test specimens as specified in S
45、ection 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
46、 exceed 0.1 % of the mass of the specimen. Unless thepurchaser and the supplier agree otherwise, bring the testspecimens 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. W
47、hen this is known,the purchaser and the supplier may agree to use a precondi-tioning cycle as specified in Practice D 1776.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
48、 Sampling RequirementsTotal Length of FieldASeams for Project, m (yd)Sample IntervalBRequirements, 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 machi
49、ne direction andcross-machine direction seams required to effect installation of 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.D 4884 96 (2003)3NOTE 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
