This standard is issued under the fixed designation D ; the number immediately 1 This test method is under the jurisdiction of ASTM Committee D35 on. Designation: D – 09Standard Test Method for TE D Tensile Properties of Geotextiles by the Wide-Width Strip. ASTM D measures the tensile properties of geotextiles using a wide-width strip specimen tensile method. ASTM D is applicable to most geotextiles.
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A number in parentheses indicates the year of last reapproval. A superscript epsilon e indicates an editorial change since the last revision or reapproval. This test method is applicable to most geotextiles that include woven fabrics, nonwoven fabrics, layered fabrics, knit fabrics, and felts that are used for geotextile application. This width, by contrast, is greater than the length of the specimen.
Some fabrics used in geotextile applications have a tendency to contract neck down under a force in the gage length area. The greater width of the specimen speci? It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Current edition approved Sept. D Terminology for Geosynthetics3 3.
Breaking toughness is calculated from work-to-break, gage length, and width of a specimen. The point from the zero force axis that the force? Summary of Method 4. Tensile strength, elongation, initial and secant modulus, and breaking toughness of the test specimen can be calculated from machine scales, dials, recording charts, or an interfaced computer.
D595 strength is not necessarily a design consideration, an alternative test method may be used for acceptance testing. Test 2 Method D for the determination of the wide-width strip tensile properties of geotextiles may be used for the acceptance testing of commercial shipments of geotextiles but caution is advised since information about between-laboratory precision is incomplete Note 6.
Comparative tests as directed in 5. Competent statistical assistance is recommended for the investigation of bias.
ASTM D4595 Wide-Width Tensile Test Equipment for Geotextiles
As a minimum, the two parties should take a group of test specimens which are as homogeneous as possible and which are from a lot of material of the type in question. The satm specimens should then be randomly assigned in equal numbers to each laboratory for testing.
If a bias is found, either its cause must be found and corrected or the purchaser and the supplier must agree to interpret future aatm results in the light of the known bias. Special clamping adaptions may be necessary with strong geotextiles or geotextiles made from glass? Specimen clamping may be modi? In any event, the procedure described in Section 10 of this test method for obtaining wide-width strip tensile strength must be maintained. Satm is used with a constant rate of extension type tension apparatus.
This is particularly the case for nonwoven geotextiles. The wide-width strip technique has been explored by the industry and is recommended in these cases for geotextile applications.
In those cases, mm 4-in. On those fabrics, the contraction effect cited in 1. Apparatus and Reagents 6. These designs have been used in the laboratory and have provided reproducible tensile strengths. These clamps may be modi? NOTE 1—The extent of the sampling for wide-width strip tensile properties is generally de? Among the options available to the purchaser and the supplier is for the purchaser to accept certi? The sample may be taken from the end portion of a roll provided there is no evidence it is distorted or different from other portions of the roll.
In cases of dispute, take a sample that will exclude fabric from the outer wrap of the roll or the inner wrap around the core. Take specimens at random from the laboratory sample, with those for the measurement of the machine direction tensile properties from different positions FIG. Test Specimen Preparation 8.
Determine the number of specimens as follows: This value for v is somewhat larger than usually found in practice. Centrally, draw two lines running the full width of the specimen, accurately perpendicular to the length dimension and separated by mm 4 in.
This helps maintain specimen integrity during the test. It must be long enough to extend through the full length of both clamps, as determined for the direction of test. Number each specimen and then cut it crosswise into two parts, one for determining the conditioned tensile strength and the other for determining the wet tensile strength; each portion shall bear the specimen number.
NOTE 4—It is recognized that some tensile tests on geotextiles are conducted using a manually applied strain rate. In any event, the strain rate described in Further use of this table is de? NOTE 2—For geotextiles which shrink excessively when wet, cut the test specimens for obtaining wet tensile strength longer in dimension than that for dry tensile strength. Equilibrium is considered to have been reached when the increase in mass of the specimen in successive weighings made at intervals of not less than 2 h does not exceed 0.
NOTE 3—It is recognized that in practice, geotextile materials are frequently not weighed to determine when moisture equilibrium has been reached.
While such a procedure cannot be accepted in cases of dispute, it may be sufficient in routine testing to expose the material to the standard atmosphere for testing for a reasonable period of time before the specimens are tested.
A time of at least 24 h has been found acceptable in most cases. When this is known, a preconditioning cycle, as described in Practice Dmay be agreed upon between contractural parties.
The time of immersion must be sufficient to wet-out the specimens thoroughly, as indicated by no signi? To obtain thorough wetting, it may be necessary or advisable to add not more than 0. At least one clamp should be supported by a free 6 Do this by having the two lines, which were previously drawn 6 3 mm 4.
The specimen length in the machine direction and cross-machine direction tests, respectively, must be parallel to the direction of application of force. Stop the machine and reset to the initial gage position. Record and report the test results to astj signi? Continue until the required number of acceptable breaks have been obtained. In the absence of other criteria for rejecting a so-called jaw break, any break occurring within 5 mm 1?
No other break shall be discarded unless the test is known to be faulty. If a jaw break is caused by damage to the specimen by the jaws, then the results should be discarded. If, however, it is merely due to randomly distributed weak places, it is a perfectly legitimate result. In some cases, it may also be caused by a concentration of stress in the astk adjacent to the jaws because they prevent the specimen from contracting in width as the force is applied.
ASTM D – Wide-Width Geotextiles
In these cases, a break near the edge of the jaws is inevitable and shall be accepted as a characteristic of the particular method of test. If any of the modi? Measure the elongation to three signi? These measurements can be made using a sealed rule taped on a line on the upper end of the specimen, in the gage area, and recording the change in length as measured from a line spaced 3 in.
In addition, the center portion of the specimen can be gaged using LVDTs or mechanical gages. By comparing, it can be determined if slippage is occuring in the clamps. Measure the force and the corresponding elongation with respect to the force axis. Calculate offset tensile modulus using Eq 6 See Fig.
Likewise, label a second point, P1 at a speci? Draw a straight line secant through both points P1 and P2 intersecting the zero force axis. Calculate secant tensile modulus using Eq 7 See Fig.
NOTE 5—Some clamping arrangements may lead to slack in the specimen within the gage area. When this occurs, that increase of the specimen length must be added and included as part of Lg, nominal gage length. At any point on this tangent line, measure the force and the corresponding elongation with respect to the zero force axis.
Measure the area bounded by the curve, the perpendicular and the elongation axis by means of an integrator or a planimeter, or cut out the area of the chart under the force? Approximately equal force increments should be used throughout the application of force having the? Describe the material or product sampled and the method of sampling used. For secant modulus, state that portion of the force?
Other portions of the force? Report the method of calculation. Precision and Bias Note 6 4 Within this limitation, the procedures in Test Method D has no known bias. This test indicated that additional clari? The major problem encountered was de?
The following procedural interpretations with respect to this method are suggested: A low force range may be used to establish the point of the applied pretension force on the force? The task group is continuing further interlaboratory testing.
It is the intent of the task group to include the above mentioned clari?
This region is considered when determining the initial geotextile modulus. This intersection, point B, is the zero elongation point from which elongation is measured. The point where line CD? This is extended to intersect the zero elongation axis at point B8. This intersection point B8 is the zero elongation point from which elongation is measured.
The intersection point A9 is the zero elongation point from which elongation is measured.