1、Designation: D 6575 00 (Reapproved 2006)Standard Test Method forDetermining Stiffness of Geosynthetics Used as TurfReinforcement Mats (TRMs)1This standard is issued under the fixed designation D 6575; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the stiff-ness of geosynthetics used as Tu
3、rf Reinforcement Mats (TRM).1.2 The method is applicable to TRMs of any fiber contentand any number of components.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate s
4、afety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 123 Terminology Relating to TextilesD 1388 Test Method for Stiffness of FabricsD 1776 Practice for Conditioning and Testing TextilesD 4354 Practice for Samp
5、ling of Geosynthetics for TestingD 4439 Terminology for GeosyntheticsD 5261 Test Method for Measuring Mass per Unit Area ofGeotextiles2.2 Federal Standards:CCC-T-191b Textile Test Methods No. 5206.233. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 bending length, n:3.1.1.1 gene
6、ral, adja measure of the interaction betweengeosynthetic weight and geosynthetic stiffness as shown by theway in which a geosynthetic bends under its own weight. Itreflects the stiffness of a geosynthetic when bent in one planeunder the force of gravity, and is one component of drape.3.1.1.2 Discuss
7、ionBending length is called drape stiffnessin Federal Specification CCC-T-191b.3.1.1.3 specific, adjthe cube root of the ratio of theflexural rigidity to the mass per unit area.3.1.2 flexural rigidity, n:3.1.2.1 general, adjresistance to bending.3.1.2.2 DiscussionResistance to bending or “flexural r
8、i-gidity” is called flex stiffness in Federal Specification CCC-T-191b.3.1.2.3 specific, adjthe couple on either end of a sampleof unit width bent into unit curvature in the absence of anytension.3.1.2.4 DiscussionThe methods measure the bendinglength. Flexural rigidity is calculated directly by mul
9、tiplyingthe cube of the bending length by the weight per unit area (see3.1.1.3).3.1.3 stiffness, nresistance to bending.3.2 DefinitionsFor definitions of other textile or geosyn-thetic terms used in this test method, refer to TerminologiesD 123 and D 4439.4. Significance and Use4.1 In general this t
10、est method is adapted from tests devel-oped for woven fabrics (previously designated as Test MethodD 1388).4.2 The cantilever test method may not be suitable fortesting products that are very limp or have a marked tendencyto curl or twist at a cut edge.Cantilever Method5. Summary of Method5.1 A spec
11、imen of the TRM is slid in a direction parallel toits long dimension, so that its end projects from the edge of ahorizontal surface. The length of overhang is measured whenthe tip of the test specimen is depressed under its own weightto the point where the line joining the tip to the edge of theplat
12、form makes an angle of 41.5 with the horizontal. One halfof this length is the bending length of the specimen. The cubeof this quantity multiplied by the weight per unit area of thegeosynthetic is the flexural rigidity.5.2 This test method is known also as the Single CantileverTest.6. Apparatus6.1 S
13、tiffness Tester, having the following parts:1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.05 on Geosyn-thetic Erosion Control.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 200
14、0. Last previous edition approved in 2000 as D 6575 00.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Avail
15、able from the Superintendent of Documents, US Government PrintingOffice, Washington, DC 204021Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.1.1 Horizontal Platform, with a minimum area of 18 by12 in. (457.2 by 304.8 mm) and having
16、 a smooth low-friction,flat surface such as polished metal or plastic. A leveling bubbleshall be incorporated in the platform, or be available forverification that the horizontal platform is level.6.1.2 Indicator, inclined at an angle of 41.5 below theplane of the platform surface.6.1.3 Weight, cons
17、isting of a metal bar not less than 4 by18 in. (101.6 by 457.2 mm) by about18 in. (3 mm) thick.6.1.4 Scale and Pointer, to measure the length of theoverhang.7. Conditioning7.1 For tests made as directed in 9.1-9.5, bring the speci-mens to a moisture equilibrium in the atmosphere for testingTRMs, tha
18、t is a temperature of 21 6 2C (70 6 4F) andrelative humidity of 60 6 10 %.8. Selection and Preparation of Specimens8.1 Cut test specimens 4 by 18 in. (101.6 by 457.2 mm). Cutfour specimens with the long direction parallel to the machinedirection and four with the long direction parallel to thetransv
19、erse (or cross-machine) direction. If the geosynthetic isnot uniform or a higher degree of precision is required, moremay be tested. Vary cutting the specimens in such a way thatthe machine direction specimens do not contain the samemachine direction yarns/filaments for the machine directiontests an
20、d cut the cross-machine direction specimens so thatseparate cross-machine direction yarns/filaments are containedin each. Avoid selvages, end pieces, and creased or foldedplaces, and handle the specimens as little as possible.NOTE 1Some TRMs are constructed from several component mate-rials and samp
21、le preparation must be performed in such a way as tomaintain the structural integrity of the product. Procedures found to besuccessful for cutting test specimens from TRMs include the use of hotknives to seal the edges and the use of bags and slip covers to keep allcomponents together during sample
22、preparation. The method of cuttingthe specimen should be included in the report.9. Procedure9.1 Make tests on conditioned specimens in the standardatmosphere for testing.9.2 Set the tester on a table or bench so that the horizontalplatform and inclined reference lines are at eye level. Adjustthe pla
23、tform so that it is horizontal as indicated by the levelingbubble.9.3 Place a specimen on the platform with the weight on topof it so that the leading edges coincide. Holding weight in ahorizontal plane, slide the specimen and weight slowly andsteadily until the leading edges project beyond the edge
24、 of theplatform. With the eye in a position so that the two inclinedlines of the tendency to twist, take the reference point at thecenter of the leading edge. Do not measure specimens thattwist more than 45. Read the length of overhang from thescale to the nearest 1 mm.9.4 Take four readings from ea
25、ch specimen, with each sideup, first at one end and then the other.9.5 Determine the mass per unit area of the geosyntheticaccording to Test Method D 5261.10. Calculation10.1 Unless otherwise specified, average the four readingsobtained from all the specimens cut parallel to the machinedirection. Do
26、 the same for those cut parallel to the cross-machine direction. In some cases it may be of interest todifferentiate between the sides of the geosynthetic by averagingthose readings made with the face side up separately fromthose with the reverse side up. If this is done, specify thedirection of ben
27、ding. Call these averages the “length ofoverhang,” and express them in centimetres. Calculate thebending length, c, in centimetres, and the flexural rigidity, G,inmg/cm by Eq 1 and 2:Bending length, c 5 0/2 (1)where Lo= the length of overhang, cm.Flexural rigidity, G 5 W 3 0/2!35 W 3 c3(2)where W =
28、weight per unit area, mg/cm2.NOTE 2To obtain the weight in mg/cm2, multiply ozlyd2by 3.39.Federal Specification CCC-T-191b gives flexural rigidity in in.-lb. Toconvert in.-lb to mg-cm, multiply by 1.15 3 106.11. Report11.1 Report to three significant figures the flexural rigidityof the machine direc
29、tion and cross-machine direction sepa-rately. If an overall average figure for the geosynthetic isrequired, calculate the geometric mean of these two values byEq 3:G 5 GMDGCD!1/2(3)where:Go= overall flexural rigidity,GMD= machine direction flexural rigidity, andGCD= cross-machine flexural rigidity.1
30、2. Precision and Bias12.1 Lack of well-defined units of stiffness makes it impos-sible to give a reliable estimate of the bias of this test method.It has been shown to give excellent correlation with a purelysubjective evaluation obtained by feeling samples for severalranges of geosynthetics of wide
31、ly differing stiffness; however,it is to be expected that inversions may exist in such acomparison. It has been found that differences in flexuralrigidity of about 10 % can just be detected subjectively, andthat this is about the limit of reliability of stiffness test results.It also has been found
32、that results obtained by differentoperators in different laboratories are as reproducible as thoseobtained by different operators within one laboratory. Theinherent stiffness of a geosynthetic may change dependingtemperature (or moisture-content if a biodegradable componentis present.)D 6575 00 (200
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36、ittee on Standards, at the address 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 6575 00 (2006)3
