1、Designation: D4884 12D4884 13Standard 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 la
2、st revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () 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 evaluating sea
3、mstrength is the width of the specimen. This is in contrast to the more narrow specimen width used in the tensile grab strength testdiscussed in Test Method D1683.1.2 This test method will provide data to indicate the seam strength that can be achieved for each particular geotextile and seamassembly
4、 construction.1.3 The values stated in SI units are to be regarded as standard. The inch-pound units given in parentheses are provided forinformation only.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of
5、 this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D76 Specification for Tensile Testing Machines for TextilesD123 Terminology Relating to TextilesD1683 Test Method for F
6、ailure in Sewn Seams of Woven Apparel FabricsD1776 Practice for Conditioning and Testing TextilesD1777 Test Method for Thickness of Textile MaterialsD4439 Terminology for GeosyntheticsD4595 Test Method for Tensile Properties of Geotextiles by the Wide-Width Strip MethodE178 Practice for Dealing With
7、 Outlying ObservationsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method2.2 Federal Standard:Fed. Std. No. 751a Stitches, Seams, and Stitchings33. Terminology3.1 Definitions:3.1.1 Adhered bonded seam strength, n for geotextiles, the maximum shear resist
8、ance, measured in kilonewtons per metre,of the junction formed by adhering together two or more planar structures.3.1.2 Adhered seam, n in geotextiles, a seam made by the application of an adhesive.3.1.3 cross-machine directionthe direction in the plane of the geotextile perpendicular to the directi
9、on of manufacture.3.1.4 geotextile, na permeable geosynthetic comprised solely of textiles.3.1.5 linear density, nmass per unit length; the quotient obtained by dividing the mass of a fiber or yarn by its length.3.1.6 machine directionthe direction in the plane of the geotextile parallel to the dire
10、ction of manufacture.1 This test method is under the jurisdiction ofASTM Committee D35 on Geosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechanical Properties.Current edition approved July 1, 2012March 15, 2013. Published April 2012April 2013. Originallyapproved in 1989. La
11、st previous edition approved in 20092012 asD4884 09e01.D4884 12. DOI: 10.1520/D4884-12.10.1520/D4884-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards
12、 Document Summary page on the ASTM website.3 Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700 Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what cha
13、nges have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the offi
14、cial document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.7 seam allowance, nthe width of geotextile used in making a seam assembly, for sewn seams bounded by the edge of thegeotextile and the furthest stitch line, and for the
15、rmally bonded seams bounded by the edge of the geotextile and the furthest seamedge.3.1.7.1 DiscussionIn geotextiles, the distance from the selvage or turned edge of the geotextile to the edge of the seam.3.1.8 seam assembly, nthe unit obtained by joining geotextile with a seam, including details su
16、ch as geotextile direction(s),seam allowance, seam width, seam type, speed, and if sewnsewing threads used and number of stitches per unit length, needletype and size, and if adhered adhesive used, amount of adhesive in weight per unit area, overlap dimension and one or both sideswith adhesive appli
17、ed and so forth.3.1.9 seam effciency, nthe ratio expressed as a percentage of seam strength to geotextile strength.3.1.10 seam design engineering, nthe procedures used to select a specific thread, a specific stitch type, and a specific seamtype to achieve the required seam strength of a sewn seam an
18、d the procedures used to select a specific seam width, specific seambonding temperature, and a specific seam speed and pressure to achieve the required seam strength of a thermally bonded seamand the type and amount of adhesive, overlap dimension and whether the adhesive was applied to one or both s
19、ides of the overlapto achieve the required seam strength of an adhered seam.3.1.11 seam interaction, nthe result of combining specific textile, a specific stitch type, and a specific seam type for a sewnseam and seam, the result of combining specific textile, a specific seam width, a specific seam s
20、peed, and applied pressure for athermally bonded seam and the type and amount of adhesive, overlap dimension and whether the adhesive was applied to one orboth sides of the overlap to achieve the required seam strength of an adhered seam.3.1.12 seam type, nin sewn geotextiles, an alphanumeric design
21、ation relating to the essential characteristics of geotextilepositioning and rows of stitching in a specific sewn geotextile seam (see Fed. Std. No. 751a).3.1.12.1 DiscussionThe first two letters of the designation show seam type; the third and subsequent letter specify a particular mating alignment
22、; thenumber designation indicates the number of rows of stitches.3.1.13 seam weld, nthe process by which a seam is formed through the thermal bonding of separate layers of geotextile.3.1.14 selvage, nthe woven edge portion of a geotextile parallel to the machine direction.3.1.14.1 DiscussionThe edge
23、 of a nonwoven geotextile cannot be easily distinguished to determine either the machine or cross-machine direction.3.1.15 sewing thread, na flexible, small diameter yarn or strand, usually treated with a surface coating, or lubricant, or both,intended to be used to stitch one or more pieces of mate
24、rial or an object to a material.3.1.16 sewn seam, nin sewn geotextiles, a series of stitches joining two or more separate plies of a material or materials ofplanar structure such as a textile geotextile.3.1.17 sewn seam strength, n for geotextiles, the maximum resistance, measured in kilonewtons per
25、 metre, of the junctionformed by stitching together two or more planar structures.3.1.18 stitch, nthe repeated unit formed by the sewing thread in the production of seams in a sewn geotextile (see Fed. Std.No. 751a).3.1.19 tensile strength, nthe maximum resistance of material to deformation in a ten
26、sile test carried to rupture; that is, thebreaking load, or force per unit cross-sectional area of the unstrained specimen.3.1.20 thermally bonded seam, n in geotextiles, a seam made by the application of thermal energy.3.1.21 thermally bonded seam strength, nfor geotextiles, the maximum shear resis
27、tance, measured in kilonewtons per metre,of the junction formed by thermally bonding together two or more planar structures.3.1.22 For definitions of other terms relating to textiles, refer to Terminology D123. For definitions of other terms relating togeotextiles, refer to Terminology D4439.4. Summ
28、ary of Test Method4.1 A seam, 200 mm (8 in.) wide is gripped across the entire width in the clamps of a tensile testing machine, operated at aprescribed rate of extension, applying a longitudinal (perpendicular) force to the specimen until the seam or geotextile ruptures.D4884 1325. Significance and
29、 Use5.1 As explained in Test Method D4595, narrow geotextile specimens demonstrate the tendency to contract (neck down) in thegage area when under stress. The wider width specimen will minimize this phenomenon in seams during strength testing. Theresults achieved in this test method can more accurat
30、ely correlate to the seam strength values anticipated in the field.5.2 This test method can be used to measure the seam strength of geotextiles, and may also be used for acceptance testing ofcommercial shipments of geotextiles. When strength is not necessarily a design consideration of seam interact
31、ion, an alternatemethod for determining the seam strength, such as Test Method D1683, may be used depending on the specification requirements.Because current information about laboratory precision is incomplete, comparative tests, as described in 5.2.1, may be advisable.5.2.1 In case of a dispute ar
32、ising from differences in reported test results when using this test method for acceptance testing ofcommercial shipments, the purchaser and the supplier should perform comparative tests to determine if there is a statistical biasbetween their laboratories. Competent statistical assistance is recomm
33、ended for the investigation of bias. As a minimum, the twoparties should take a group of test specimens from the same lot of geotextile, that utilize a like method of seam assembly to achieveseam interaction. The specimens should then be randomly assigned in equal number to each laboratory for testi
34、ng. If a bias isfound, either its cause must be determined and corrected, or the purchaser and the supplier must agree to interpret future test resultsin light of the known bias.5.3 Although other methods of determining seam strength are available, this test method, that measures wide specimens, wil
35、lmore accurately correlate to the anticipated performance in the field.5.4 This test method can be used to help determine seam design engineering for the geotextiles being evaluated.6. Apparatus6.1 Tensile Testing Machine, must be of the constant-rate-of-extension (CRE) type, conforming to Specifica
36、tion D76 andequipped with a recorder having an adequate pen response or interfaced computer to record the load elongation curve. The machinemust be set to a rate of extension of 10 6 3 %/min.6.2 ClampsThe clamps shall be wide enough to grip the entire width of the specimen and have the appropriate c
37、lampingpower to hold the test specimen in place without crushing (damaging) the machine direction and cross-machine direction yarns.6.2.1 Caution must be taken to ensure that the type of clamp used is adequate for the seam strength being measured.6.3 Size of Jaw FacesEach clamp shall have a bearing
38、face measuring wider than the width of the specimen, 200 mm (8 in.)and a minimum of 50 mm (2 in.) in length, in the direction of the applied force. The size of jaw faces does not apply if roller clampsare used.7. Sampling for Acceptance Testing and Number of Specimens7.1 Division into Lots and Lot S
39、ample Divide the material into lots and take a lot sample as described in an applicable materialspecification, or as agreed upon between the purchaser and the supplier. In the absence of an applicable material specification orprior agreement between the purchaser and the supplier, sampling and testi
40、ng intervals should be agreed upon between thepurchaser and the supplier.7.1.1 When the installation project requires that seams are made in both the machine and cross-machine directions, the numberof samples and the subsequent specimens will increase proportionately.7.2 Laboratory SamplesAt a labor
41、atory sample, cut a minimum of two swatches of geotextile from each of the lot unitsselected for testing. The swatches must be a minimum of 2000 mm (79 in.) in length and a minimum of 300 mm (12 in.) in width.The lengthwise direction of these swatches must be cut from opposite ends and opposite side
42、s of the lot sample rolls and shouldbe parallel to the direction in which the seam will be made.7.2.1 When seams are made in both the machine and cross-machine direction, it is suggested that some type of special coloridentification marking be used to distinguish one from the other.7.2.2 These swatc
43、hes are then joined using the best seam engineering techniques determined by the purchaser and the supplierto achieve seam interaction.7.2.3 It will be necessary to cut a sufficient number of swatches for both wet and conditioned tests.7.3 Test Specimens:7.3.1 Number of SpecimensIn the absence of an
44、 applicable specification or prior agreement between the purchaser and thesupplier, prepare at least six test specimens from the laboratory samples.7.3.2 Test Specimen SizePrepare test specimens from the laboratory sample. Each specimen should be approximately 250 mm(10 in.) wide with a stitch line
45、in the center for sewn seams or approximately 200 mm (8 in.) wide with the seam weld in the centerfor thermally bonded or adhered seams running parallel to either the machine or cross-machine directions as shown in Fig. 1(a)for sewn seams or seams, Fig. 1(b) for thermally bonded seams or Fig. 1 (c)
46、for adhered seams.7.3.2.1 Cut this wider specimen for sewn seams as shown in Fig. 1(a) to achieve a final test specimen width of 200 mm (8 in.).When removing the shaded area from a specimen as shown in Fig. 1(a), the angles between the 25-mm extensions which areparallel to the seam and that section
47、of the specimen having a finished width of 200 mm is 90.D4884 1337.3.2.2 For some seaming patterns, cutting the thread may lead to a loss of the integrity of the seam, and thus to anunderestimation of the seam strength. For these patterns, some means shall be used to lock the thread in place, such a
48、s using glue,or mechanically locking the thread on both ends of the seam by un-sewing the seam over a maximum length of 25mm, withoutdamaging the sewing thread, in order to have at least 200 mm of intact seam centered in the axis of the specimen. Both upper andlower threads of the seam shall then be
49、 tied together to avoid any further modification to the structure of the stitch during the test.FIG. 1 (a) Test Specimen Preparation for Sewn Seam (Front View)FIG. 1 (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 1348. Sampling of Field Seams and Factory Seams8.1 The evaluation of field seams and factory seams will be made by taking samples at the stipulated intervals directed in Table1 unless otherwise stated.NOTE 1
