ASTM D6818-2002(2009) 431 Standard Test Method for Ultimate Tensile Properties of Turf Reinforcement Mats《草皮加强网基本拉伸特性的标准试验方法》.pdf

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1、Designation: D 6818 02 (Reapproved 2009)Standard Test Method forUltimate Tensile Properties of Turf Reinforcement Mats1This standard is issued under the fixed designation D 6818; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the

2、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 deter-mining the tensile properties of Turf Reinforcement Ma

3、ts(TRM).1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are provided forinformation purposes only.1.3 This standard does not apply to TRMs made of com-posite materials where the component providing the reinforce-ment cannot be tested for tensile s

4、trength with the procedureherein described. In this case, the established ASTM testingmethod, which is most appropriate for that material, shall beused instead.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the use

5、r 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:2D76 Specification for Tensile Testing Machines for Textiles3. Terminology3.1 Definitions:3.1.1 breaking load, nt

6、he maximum force applied to aspecimen in a tensile test carried to rupture.3.1.1.1 DiscussionMaterials that are brittle usually rup-ture at the maximum force. Materials that are ductile usuallyexperience a maximum force before rupturing.3.1.2 constant rate of extension (CRE) tensile testingmachinea

7、testing machine in which the rate of increase ofspecimen length is uniform with time.3.1.3 elongation, nthe ratio of the extension of a materialto the length of the material prior to stretching. (Compareextension.)3.1.4 extension, nthe change in length of a material due tostretching. (Compare elonga

8、tion.)3.1.5 rupture, vthe act of bursting.3.1.6 strip test, nin TRM testing, a tensile test in whichthe full width of the specimen is gripped in the clamps.3.1.7 tensile test, nin geosynthetics, a test in which ageosynthetic material is stretched in one direction to determinethe force - elongation c

9、haracteristics, the breaking force, or thebreaking elongation.4. Summary of Test Method4.1 A test specimen is clamped in a tensile testing machineand a force applied to the specimen until it breaks. Values forthe breaking force and elongation of the test specimen areobtained from machine scales, dia

10、ls, autographic recordingcharts, or a computer interfaced 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 satisfac-tory for acceptance testing of commercial shipments of TurfReinforcement M

11、ats since the method has been used exten-sively in the trade for acceptance testing.5.1.1 In case of disagreement arising from differences inreported test values when using this test method for acceptancetesting of commercial shipments, the purchaser and the sup-plier should conduct comparative test

12、s to determine if there isstatistical bias between their laboratories. Competent statisticalassistance is recommended for the investigation of bias. As aminimum, the two parties should take a group of test specimenwhich are as homogeneous as possible and are from a lot ofmaterial of the type in ques

13、tion. The test specimen should thenbe randomly assigned in equal numbers to each laboratory fortesting. The average results from the two laboratories should becompared using Students t-test for unpaired data and anacceptable probability level chosen by the two parties beforetesting is begun. If bias

14、 is found, either its cause must be foundand corrected, or the purchaser and the supplier must agree tointerpret future results in the light of the known bias.1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.05 on

15、Geosyn-thetic Erosion Control.Current edition approved June 1, 2009. Published July 2009. Originally approvedin 2002. Last previous edition approved in 2002 as D 6818 02.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annu

16、al Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Apparatus6.1 Tensile Testing Machine, of the Constant Rate of Exten-sion

17、(CRE) type conforming to Specification D76, withrespect to force indication, working range, capacity, andelongation indicator and designed for operation at a speed of300 6 10 mm/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 upo

18、n surface. The facesshall be parallel and have machining centers with respect toone another in the same clamp and to the corresponding jawface of the other clamp. The jaw faces shall measure at least 10mm (0.5 in.) wider than the specimen being tested and at least25 mm (1.0 in.) in height.7. Samplin

19、g7.1 Lot SampleTake a lot sample as directed in theapplicable material specifications.7.2 Laboratory SampleFrom each roll or piece of TRMtaken from the lot sample, cut at least one laboratory samplethe full width of the TRM and1m(1yd)along the edge in themachine direction.7.3 Test SpecimenFrom each

20、laboratory sample, take fivespecimens from each direction for each test.7.4 Cut specimens with their long dimension parallel eitherto the machine direction or to the cross machine direction, orcut specimens for testing both directions as required. Unlessotherwise specified, take specimens no nearer

21、to the machinedirection edge of the TRM than one tenth of the width of theTRM.7.5 Cut each specimen 100 mm (4 in.) wide, by at least 150mm (6 in.) long.NOTE 1The length of the specimen depends on the type of clampsbeing used. The specimen should be long enough to extend through theclamps and project

22、 at least 12.5 mm (12 in.) at each end and provide a gagelength of 75 mm.8. Conditioning8.1 Bring the specimens to the moisture and temperatureequilibrium in the atmosphere for testing TRMs, that is atemperature of 21 6 2C (70 6 4F) and a relative humidity of60 6 10 %.9. Procedure9.1 Set gage length

23、 to 75 mm.9.2 Mount the specimen securely in the clamp of the testingmachine. Take care that the specimen is centrally located andthat the long dimension is as nearly parallel as possible to thedirection of force application. Be sure that the tension on thespecimen is uniform across the clamped widt

24、h. Clamps whichare too tight will produce breaks at the clamp line; clampswhich are too loose will cause slippage.9.3 Operate the machine and break the specimen. The rateof extension should be 300 6 10 mm/min.9.4 Read the breaking force and elongation, from themechanism provided for such purpose. Re

25、cord machine andcross machine direction results separately. If desired, additionalpoints along the stress/strain curve can be recorded as well.9.5 For some machines, data may be obtained using aninterfaced computer.9.6 If a specimen slips in the jaws, or breaks at the edge ofor in the jaws, or if fo

26、r any reason the results falls markedlybelow the average of the set of specimens, discard the resultand take another specimen. Continue this until the requirednumbers of breaks have been obtained.NOTE 2It is difficult to determine the precise reason that certainspecimens break near the edge of the j

27、aws. If such a break is by damageto the specimen by the jaws, then the results should be discarded. If,however, the break is merely due to randomly distributed weak places, itis a legitimate result. In some cases, it may also be caused by aconcentration of stress in the area adjacent to the jaws bec

28、ause the jawsprevent the specimen from contracting in the width as the force is applied.In such cases, a break near the edge of the jaw is inevitable and should beaccepted as a characteristic of the particular method of test.10. Calculation10.1 Breaking Force per Unit WidthFor each laboratorysample,

29、 calculate the average of the breaking force observedfor all acceptable specimens, that is, the maximum forceexerted on the specimen as read directly from the testingmachine indicating mechanism and divide this force by thewidth of the strip. The resulting value is expressed in KiloNewtons/Meter.10.

30、2 ElongationFor each laboratory sample, calculate theaverage of the elongation observed for all acceptable speci-mens, that is, the elongation that corresponds to the maximumforce as stated above, as read directly from the testing machineindicating mechanism. The elongation is expressed in percent.1

31、1. Report11.1 State that the specimens were tested as directed in TestMethod D 6818. Describe the material or product sampled andthe method of sampling used.11.2 Report the following for each laboratory sample:11.2.1 The average breaking force per unit width of accept-able specimens for each test.11

32、.2.2 The average elongation at break of acceptable speci-mens for each test.11.2.3 Number of specimens tested in each direction.11.2.4 Size of jaw faces used.12. Precision and Bias12.1 PrecisionThe precision of the strip tensile test pro-cedure of this test method is being established.12.2 BiasThe t

33、rue value of the breaking force and elon-gation of fabric can be defined only in terms of specific testmethods. Within this limitation, the procedure in this testmethod has no known bias.13. Keywords13.1 breaking force; elongation; turf reinforcement matD 6818 02 (2009)2ASTM International takes no p

34、osition respecting the 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 responsib

35、ility.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 should be addressed to

36、ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the addre

37、ss shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 6818 02 (2009)3