1、Designation: D6818 02 (Reapproved 2009)D6818 14Standard Test Method forUltimate Tensile Properties of Turf ReinforcementMatsRolled Erosion Control Products1This standard is issued under the fixed designation D6818; the number immediately following the designation indicates the year oforiginal adopti
2、on or, in the case of revision, the year of last 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 strip test procedures for determining the tensile
3、properties of Turf Reinforcement Mats(TRM).Rolled Erosion Control Products (RECP).1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for informationpurposes only.1.3 This standard does not apply to TRMsRECPs made of composite materials
4、where the component providing thereinforcement cannot be tested for tensile strength with the procedure herein described. In this case, the established ASTM testingmethod, which is most appropriate for that material, shall be used instead.1.4 This standard does not purport to address all of the safe
5、ty concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D76D76/D76M Specification for Tensi
6、le Testing Machines for TextilesE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method3. Terminology3.1 Definitions:3.1.1 breaking load, nthe maximum force applied to a specimen in a
7、tensile test carried to rupture.3.1.1.1 DiscussionMaterials that are brittle usually rupture at the maximum force. Materials that are ductile usually experience a maximum forcebefore rupturing.3.1.2 constant rate of extension (CRE) tensile testing machinea testing machine in which the rate of increa
8、se of specimenlength is uniform with time.3.1.3 elongation, nthe ratio of the extension of a material to the length of the material prior to stretching. (Compare extension.)3.1.4 extension, nthe change in length of a material due to stretching. (Compare elongation.)3.1.5 rupture, vthe act of burstin
9、g.3.1.6 strip test, nin TRMRECP testing, a tensile test in which the full width of the specimen is gripped in the clamps.3.1.7 tensile test, nin geosynthetics, a test in which a geosynthetic material is stretched in one direction to determine the force- elongation characteristics, the breaking force
10、, or the breaking elongation.1 This test method is under the jurisdiction of ASTM Committee D35 on Geosynthetics and is the direct responsibility of Subcommittee D35.05 on Geosynthetic ErosionControl.Current edition approved June 1, 2009May 1, 2014. Published July 2009May 2014. Originally approved i
11、n 2002. Last previous edition approved in 20022009 as D6818 02. 02 (2009). DOI: 10.1520/D6818-02R09.10.1520/D6818-14.2 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
12、the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes
13、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 official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United
14、 States14. Summary of Test Method4.1 A test specimen is clamped in a tensile testing machine and a force applied to the specimen until it breaks. Values for thebreaking force and elongation of the test specimen are obtained from machine scales, dials, autographic recording charts, or acomputer inter
15、faced with the testing machine. Also, points along the stress/strain curve can be reported.5. Significance and Use5.1 The strip test in this test method is considered satisfactory for acceptance testing of commercial shipments of TurfReinforcement Mats Rolled Erosion Control Products since the metho
16、d has been used extensively in the trade for acceptancetesting.5.1.1 In case of disagreement arising from differences in reported test values when using this test method for acceptance testingof commercial shipments, the purchaser and the supplier should conduct comparative tests to determine if the
17、re is statistical biasbetween their laboratories. Competent statistical assistance is recommended for the investigation of bias. As a minimum, the twoparties should take a group of test specimen which are as homogeneous as possible and are from a lot of material of the type inquestion. The test spec
18、imen should then be randomly assigned in equal numbers to each laboratory for testing. The average resultsfrom the two laboratories should be compared using Students t-test for unpaired data and an acceptable probability level chosenby the two parties before testing is begun. If bias is found, eithe
19、r its cause must be found and corrected, or the purchaser and thesupplier must agree to interpret future results in the light of the known bias.6. Apparatus6.1 Tensile Testing Machine, of the Constant Rate of Extension (CRE) type conforming to Specification D76D76/D76M, withrespect to force indicati
20、on, working range, capacity, and elongation indicator and designed for operation at a speed of 300 6 10mm/min (12 6 0.5 in./min).6.2 Clamps and Jaw FacesEach jaw face shall be smooth, flat, and with a metallic or other agreed upon surface. The facesshall be parallel and have machining centers with r
21、espect to one another in the same clamp and to the corresponding jaw face ofthe other clamp. The jaw faces shall measure at least 10 mm (0.5 in.) wider than the specimen being tested and at least 25 mm(1.0 in.) in height.7. Sampling7.1 Lot SampleTake a lot sample as directed in the applicable materi
22、al specifications.7.2 Laboratory SampleFrom each roll or piece of TRMRECP taken from the lot sample, cut at least one laboratory samplethe full width of the TRMRECP and 1 m (1 yd) along the edge in the machine direction.7.3 Test SpecimenFrom each laboratory sample, take five specimens from each dire
23、ction for each test.7.4 Cut specimens with their long dimension parallel either to the machine direction or to the cross machine direction, or cutspecimens for testing both directions as required. Unless otherwise specified, take specimens no nearer to the machine directionedge of the TRMRECP than o
24、ne tenth of the width of the TRM.RECP.7.5 Cut each specimen 100 mm (4 in.) wide, by at least 150 mm (6 in.) long.NOTE 1The length of the specimen depends on the type of clamps being used. The specimen should be long enough to extend through the clampsand project at least 12.5 mm (12 in.) at each end
25、 and provide a gage length of 75 mm.8. Conditioning8.1 Bring the specimens to the moisture and temperature equilibrium in the atmosphere for testing TRMs,RECPs, that is atemperature of 21 6 2C (70 6 4F) and a relative humidity of 60 6 10 %.9. Procedure9.1 Set gage length to 75 mm.9.2 Mount the speci
26、men securely in the clamp of the testing machine. Take care that the specimen is centrally located and thatthe long dimension is as nearly parallel as possible to the direction of force application. Be sure that the tension on the specimenis uniform across the clamped width. Clamps which are too tig
27、ht will produce breaks at the clamp line; clamps which are too loosewill cause slippage.9.3 Operate the machine and break the specimen. The rate of extension should be 300 6 10 mm/min.mm/min (12 6 0.5in./min).9.4 Read the breaking force and elongation, from the mechanism provided for such purpose. R
28、ecord machine and cross machinedirection results separately. If desired, additional points along the stress/strain curve can be recorded as well.9.5 For some machines, data may be obtained using an interfaced computer.D6818 1429.6 If a specimen slips in the jaws, or breaks at the edge of or in the j
29、aws, or if for any reason the results falls markedly belowthe average of the set of specimens, discard the result and take another specimen. Continue this until the required numbers ofbreaks have been obtained.NOTE 2It is difficult to determine the precise reason that certain specimens break near th
30、e edge of the jaws. If such a break is by damage to thespecimen by the jaws, then the results should be discarded. If, however, the break is merely due to randomly distributed weak places, it is a legitimateresult. In some cases, it may also be caused by a concentration of stress in the area adjacen
31、t to the jaws because the jaws prevent the specimen fromcontracting in the width as the force is applied. In such cases, a break near the edge of the jaw is inevitable and should be accepted as a characteristicof the particular method of test.10. Calculation10.1 Breaking Force per Unit Width For eac
32、h laboratory sample, calculate the average of the breaking force observed for allacceptable specimens, that is, the maximum force exerted on the specimen as read directly from the testing machine indicatingmechanism and divide this force by the width of the strip. The resulting value is expressed in
33、 Kilo Newtons/Meter.10.2 ElongationFor each laboratory sample, calculate the average of the elongation observed for all acceptable specimens,that is, the elongation that corresponds to the maximum force as stated above, as read directly from the testing machine indicatingmechanism. The elongation is
34、 expressed in percent.11. Report11.1 State that the specimens were tested as directed in Test Method D6818. Describe the material or product sampled and themethod of sampling used.11.2 Report the following for each laboratory sample:11.2.1 The average breaking force per unit width of acceptable spec
35、imens for each test.11.2.2 The average elongation at break of acceptable specimens for each test.11.2.3 Number of specimens tested in each direction.11.2.4 Size of jaw faces used.12. Precision and Bias312.1 PrecisionThe precision of the strip tensile test procedure of this test method is being estab
36、lished.based on aninterlaboratory study of D6818 Standard Test Method for Ultimate Tensile Properties of Turf Reinforcement Mats, conducted in2013. Four laboratories participated in this study. Each of the labs reported three replicate test results for two different types ofmats and a double net bla
37、nket. Every “test result” reported represents the average of five measurements taken from a sample.Except for the ultimate use of data from only four laboratories, Practice E691 was followed for the design and analysis of the data;the details are given in ASTM Research Report No. RR:D35-1016.12.1.1
38、Repeatability (r)The difference between repetitive results obtained by the same operator in a given laboratory applyingthe same test method with the same apparatus under constant operating conditions on identical test material within short intervalsof time would in the long run, in the normal and co
39、rrect operation of the test method, exceed the following values only in one casein 20.12.1.1.1 Repeatability can be interpreted as the maximum difference between two results, obtained under repeatabilityconditions, that is accepted as plausible due to random causes under normal and correct operation
40、 of the test method.12.1.1.2 Repeatability limits are listed in Tables 1-4.12.1.2 Reproducibility (R)The difference between two single and independent results obtained by different operators applyingthe same test method in different laboratories using different apparatus on identical test material w
41、ould, in the long run, in thenormal and correct operation of the test method, exceed the following values only in one case in 20.12.1.2.1 Reproducibility can be interpreted as the maximum difference between two results, obtained under reproducibilityconditions, that is accepted as plausible due to r
42、andom causes under normal and correct operation of the test method.3 Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D35-1016. Contact ASTM CustomerService at serviceastm.org.TABLE 1 Tensile Elongation of Cross-Machine Direction
43、 (%)Material AverageARepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitx Sr SR r RDouble Net Blanket 15.373 1.084 1.748 3.036 4.894Double Net TRM#1 20.003 0.911 2.641 2.550 7.395Double Net TRM#2 26.639 1.217 4.300 3.408 12.041A The average of the lab
44、oratories calculated averages.D6818 14312.1.2.2 Reproducibility limits are listed in Tables 1-4.12.1.3 The above terms (repeatability limit and reproducibility limit) are used as specified in Practice E177.12.1.4 Any judgment in accordance with statements 12.1.1 and 12.1.2 will have an approximate 9
45、5 % probability of beingcorrect. The precision statistics obtained in this ILS must not be treated as exact mathematical quantities which are applicable toall circumstances and uses. The limited number of materials tested may lead to times when differences greater than predicted bythe ILS results wi
46、ll arise, sometimes with considerably greater or smaller frequency than the 95 % probability limit would imply.12.2 BiasThe true value of the breaking force and elongation of fabric can be defined only in terms of specific test methods.Within this limitation, the procedure in this test method has no
47、 known bias.At the time of the study, there was no accepted referencematerial suitable for determining the bias for this test method, therefore no statement on bias is being made.12.3 The precision statement was determined through statistical examination of 144 results, from four laboratories, on th
48、reematerials.12.4 To judge the equivalency of two test results, it is recommended to choose the material closest in characteristics to the testmaterial.13. Keywords13.1 breaking force; elongation; turf reinforcement matrolled erosion control productsASTM International takes no position respecting th
49、e validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand
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