ASTM D4884-96(2003)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D4884–96 (Reapproved 2003)
Standard Test Method for
Strength of Sewn or Thermally Bonded Seams of
Geotextiles
This standard is issued under the fixed designation D 4884; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope E 691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of Test Methods
1.1 Thistestmethodcoverstheseamstrengthofgeotextiles.
2.2 Federal Standard:
The primary distinction of this test method for evaluating seam
Fed. Std. No. 751a Stitches, Seams, and Stitchings
strength is the width of the specimen. This is in contrast to the
more narrow specimen width used in the tensile grab strength
3. Terminology
test discussed in Test Method D 1683.
3.1 Definitions:
1.2 This test method will provide data to indicate the seam
3.1.1 cross-machine direction—the direction in the plane of
strength that can be achieved for each particular geotextile and
the geotextile perpendicular to the direction of manufacture.
seam assembly construction.
3.1.2 geotextile, n—a permeable geosynthetic comprised
1.3 The values stated in SI units are to be regarded as
solely of textiles.
standard. The inch-pound units given in parentheses are
3.1.3 linear density, n—mass per unit length; the quotient
provided for information only.
obtained by dividing the mass of a fiber or yarn by its length.
1.4 This standard does not purport to address all of the
3.1.4 machine direction—the direction in the plane of the
safety concerns, if any, associated with its use. It is the
geotextile parallel to the direction of manufacture.
responsibility of the user of this standard to establish appro-
3.1.5 seam allowance, n—the width of geotextile used in
priate safety and health practices and determine the applica-
making a seam assembly, for sewn seams bounded by the edge
bility of regulatory limitations prior to use.
of the geotextile and the furthest stitch line, and for thermally
2. Referenced Documents bonded seams bounded by the edge of the geotextile and the
furthest seam edge.
2.1 ASTM Standards:
3.1.5.1 Discussion—In geotextiles, the distance from the
D 76 Specification for Tensile Testing Machines for Tex-
selvageorturnededgeofthegeotextiletotheedgeoftheseam.
tiles
3.1.6 seam assembly, n—the unit obtained by joining geo-
D 123 Terminology Relating to Textiles
textile with a seam, including details such as geotextile
D 1683 Test Method for Failure in Sewn Seams of Woven
direction(s), seam allowance, seam width, seam type, speed,
Fabrics
and if sewn—sewing threads used and number of stitches per
D 1776 Practice for Conditioning Textiles for Testing
unit length, needle type and size, and so forth.
D 1777 Method for Measuring Thickness of Textile Mate-
3.1.7 seam effıciency, n—theratioexpressedasapercentage
rials
3 of seam strength to geotextile strength.
D 4354 Practice for Sampling of Geosynthetics for Testing
3.1.8 seam design engineering, n—the procedures used to
D 4439 Terminology for Geosynthetics
select a specific thread, a specific stitch type, and a specific
D 4595 Test Method for Tensile Properties of Geotextiles
seam type to achieve the required seam strength of a sewn
by the Wide Width Strip Method
seam and the procedures used to select a specific seam width,
D 4632 Test Method for Grab Breaking Load and Elonga-
specific seam bonding temperature, and a specific seam speed
tion of Geotextiles
4 and pressure to achieve the required seam strength of a
E 178 Practice for Dealing with Outlying Observations
thermally bonded seam.
3.1.9 seam interaction, n—the result of combining specific
This test method is under the jurisdiction of ASTM Committee D35 on
textile, a specific stitch type, and a specific seam type for a
Geosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechani-
cal Properties.
Current edition approved Feb. 10, 1996. Published June 1996. Originally
published as D 4884 – 89. Last previous edition D 4884 – 90.
Annual Book of ASTM Standards, Vol 07.01.
3 5
Annual Book of ASTM Standards, Vol 04.13. AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
Annual Book of ASTM Standards, Vol 14.02. Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4884–96 (2003)
sewn seam and the result of combining specific textile, a testing. The results achieved in this test method can more
specific seam width, a specific seam speed, and applied accurately correlate to the seam strength values anticipated in
pressure for a thermally bonded seam. the field.
3.1.10 seam type, n—in sewn geotextiles, an alphanumeric 5.2 This test method can be used to measure the seam
designationrelatingtotheessentialcharacteristicsofgeotextile strength of geotextiles, and may also be used for acceptance
positioning and rows of stitching in a specific sewn geotextile testing of commercial shipments of geotextiles. When strength
seam (see Fed. Std. No. 751a). isnotnecessarilyadesignconsiderationofseaminteraction,an
3.1.10.1 Discussion—Thefirsttwolettersofthedesignation alternate method for determining the seam strength, such as
show seam type; the third and subsequent letter specify a Test Method D 1683, may be used depending on the specifi-
particular mating alignment; the number designation indicates cation requirements. Because current information about labo-
the number of rows of stitches. ratory precision is incomplete, comparative tests, as described
3.1.11 seam weld, n—the process by which a seam is in 5.2.1, may be advisable.
formed through the thermal bonding of separate layers of 5.2.1 In case of a dispute arising from differences in
geotextile. reported test results when using this test method for acceptance
3.1.12 selvage, n—the woven edge portion of a geotextile testing of commercial shipments, the purchaser and the sup-
parallel to the machine direction. plier should perform comparative tests to determine if there is
3.1.12.1 Discussion—The edge of a nonwoven geotextile a statistical bias between their laboratories. Competent statis-
cannot be easily distinguished to determine either the machine tical assistance is recommended for the investigation of bias.
or cross-machine direction. As a minimum, the two parties should take a group of test
3.1.13 sewing thread, n—a flexible, small diameter yarn or specimens from the same lot of geotextile, that utilize a like
strand, usually treated with a surface coating, or lubricant, or method of seam assembly to achieve seam interaction. The
both, intended to be used to stitch one or more pieces of specimens should then be randomly assigned in equal number
material or an object to a material. to each laboratory for testing. If a bias is found, either its cause
3.1.14 sewn seam, n—in sewn geotextiles, a series of must be determined and corrected, or the purchaser and the
stitches joining two or more separate plies of a material or supplier must agree to interpret future test results in light of the
materials of planar structure such as a textile geotextile. known bias.
3.1.15 sewn seam strength, n— for geotextiles, the maxi- 5.3 Although other methods of determining seam strength
mum resistance, measured in kilonewtons per metre, of the are available, this test method, that measures wide specimens,
junction formed by stitching together two or more planar willmoreaccuratelycorrelatetotheanticipatedperformancein
structures. the field.
3.1.16 stitch, n—the repeated unit formed by the sewing 5.4 This test method can be used to help determine seam
threadintheproductionofseamsinasewngeotextile(seeFed. design engineering for the geotextiles being evaluated.
Std. No. 751a).
6. Apparatus
3.1.17 tensile strength, n—the maximum resistance of ma-
terial to deformation in a tensile test carried to rupture; that is, 6.1 Tensile Testing Machine, must be of the constant-rate-
of-extension(CRE)type,conformingtoSpecificationD 76and
the breaking load, or force per unit cross-sectional area of the
unstrained specimen. equipped with a recorder having an adequate pen response or
interfaced computer to record the load elongation curve. The
3.1.18 thermally bonded seam, n— in geotextiles, a seam
made by the application of thermal energy. machine must be set to a rate of extension of 10 6 3 %/min.
6.2 Clamps—The clamps shall be wide enough to grip the
3.1.19 thermally bonded seam strength, n—for geotextiles,
the maximum shear resistance, measured in kilonewtons per entirewidthofthespecimenandhavetheappropriateclamping
power to hold the test specimen in place without crushing
metre, of the junction formed by thermally bonding together
(damaging) the machine direction and cross-machine direction
two or more planar structures.
yarns.
3.1.20 For definitions of other terms relating to textiles,
6.2.1 Caution must be taken to ensure that the type of clamp
refer to Terminology D 123. For definitions of other terms
used is adequate for the seam strength being measured.
relating to geotextiles, refer to Terminology D 4439.
6.3 Size of Jaw Faces—Each clamp shall have a bearing
4. Summary of Test Method
face measuring wider than the width of the specimen, 200 mm
4.1 Aseam, 200 mm (8 in.) wide is gripped across the entire (8 in.) and a minimum of 50 mm (2 in.) in length, in the
width in the clamps of a tensile testing machine, operated at a direction of the applied force. The size of jaw faces does not
prescribed rate of extension, applying a longitudinal (perpen- apply if roller clamps are used.
dicular) force to the specimen until the seam or geotextile
7. Sampling for Acceptance Testing and Number of
ruptures.
Specimens
5. Significance and Use
7.1 Division into Lots and Lot Sample—Dividethematerial
5.1 As explained in Test Method D 4595, narrow geotextile into lots and take a lot sample as described in an applicable
specimensdemonstratethetendencytocontract(neckdown)in materialspecification,orasagreeduponbetweenthepurchaser
the gage area when under stress. The wider width specimen and the supplier. In the absence of an applicable material
will minimize this phenomenon in seams during strength specification or prior agreement between the purchaser and the
D4884–96 (2003)
supplier, sampling and testing intervals should be agreed upon
between the purchaser and the supplier.
7.1.1 When the installation project requires that seams are
made in both the machine and cross-machine directions, the
number of samples and the subsequent specimens will increase
proportionately.
7.2 Laboratory Samples—At a laboratory sample, cut a
minimum of two swatches of geotextile from each of the lot
units selected 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 sides of the lot sample
rolls and should be 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
FIG. 1 (b) Test Specimen Preparation for Thermally Bonded Seam
special color identification marking be used to distinguish one (Front View) (continued)
from the other.
7.2.2 These swatches are then joined using the best seam
8. Sampling of Field Seams and Factory Seams
engineering techniques determined by the purchaser and the
8.1 The evaluation of field seams and factory seams will be
supplier to achieve seam interaction.
made by taking samples at the stipulated intervals directed in
7.2.3 It will be necessary to cut a sufficient number of
Table 1 unless otherwise stated.
swatches for both wet and conditioned tests.
7.3 Test Specimens:
NOTE 1—To prevent the unnecessary waste of geotextile or impede the
installation, it should be agreed upon between the supplier and the
7.3.1 Number of Specimens—In the absence of an appli-
purchaserthatallseamsamplescanbetakenfromalternatesidesofpanels
cable specification or prior agreement between the purchaser
at or near the end of the rolls.
and the supplier, prepare at least six test specimens from the
laboratory samples. 8.2 The lengthwise direction of these swatches should be
parallel to the direction of the seam, either in the machine or
7.3.2 Test Specimen Size—Prepare test specimens from the
laboratory sample. Each specimen should be approximately cross-machine direction.
8.2.1 It will be necessary to cut additional swatches for both
250 mm (10 in.) wide with a stitch line in the center for sewn
seams or approximately 200 mm (8 in.) wide with the seam wet and conditioned tests to be performed.
8.3 Prepare test specimens as specified in Section 7, 7.3.2,
weld in the center for thermally bonded seams running parallel
to either the machine or cross-machine directions as shown in and, if sewn, 7.3.2.1.
Fig. 1(a) for sewn seams or Fig. 1(b) for thermally bonded
9. Conditioning
seams.
7.3.2.1 Cut this wider specimen for sewn seams as shown in
9.1 Bring the specimens to moisture equilibrium in the
Fig. 1(a) to achieve a final test specimen width of 200 mm (8 atmospherefortestinggeotextiles.Equilibriumisconsideredto
in.). When removing the shaded area from a specimen as
have been reached when the increase in mass of the specimen
shown in Fig. 1(a), the angles between the 25-mm extensions in successive weighings made at intervals of not less than 2 h
which are parallel to the seam and that section of the specimen
does not exceed 0.1 % of the mass of the specimen. Unless the
having a finished width of 200 mm is 90°. purchaser and the supplier agree otherwise, bring the test
specimens to moisture equilibrium starting with the condition
in which they were received.
9.1.1 Certain fibers may exhibit slow moisture equalization
rates 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 Practice D 1776.
TABLE 1 Seam Quality Control Sampling Requirements
A B
Total Length of Field Sample Interval
Seams for Project, m (yd) Requirements, 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)
A
Total length of field seams for project is the sum of all machine direction and
cross-machine direction seams required to effect installation of geotextile(s).
B
Samples will be taken at stipulated intervals along the total length of the field
seams. The num
...