1、Designation: D6575 14Standard Test Method forDetermining Stiffness of Geosynthetics Used as TurfReinforcement Mats (TRMs)1This standard is issued under the fixed designation D6575; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e 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 the determination of the stiff-ness of geosynthetics used asTurf Reinforcement Mats
3、(TRM).1.2 The method is applicable to TRMs of any fiber contentand any number of components.1.3 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered st
4、andard.1.4 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 safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Refer
5、enced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD1388 Test Method for Stiffness of FabricsD1776 Practice for Conditioning and Testing TextilesD4354 Practice for Sampling of Geosynthetics and RolledErosion Control Products(RECPs) for TestingD4439 Terminology for GeosyntheticsD
6、5261 Test Method for Measuring Mass per Unit Area ofGeotextiles2.2 Federal Standards:3CCC-T-191b Textile Test Methods No. 5206.23. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 bending length, n:3.1.1.1 general, adja measure of the interaction betweengeosynthetic weight and geo
7、synthetic 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 DiscussionBending length is called drape stiffnessin Federal Specification CCC
8、-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 ri-gidity” is called flex stiffness in Federal Specification CCC-T-191b.
9、3.1.2.3 specific, adjthe couple on either end of a sample ofunit 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 multiplyingthe cube of the bending length by the weight per unit area (see
10、3.1.1.3).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 TerminologiesD123 and D4439.4. Significance and Use4.1 In general this test method is adapted from tests devel-oped for woven fabrics (previously
11、 designated as Test MethodD1388).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 specimen of the TRM is slid in a direction parallel toits long dimension, so t
12、hat 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 theplatform makes an angle of 41.5 with the horizontal. One half1This test method
13、 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 March 15, 2014. Published April 2014. Originallyapproved in 2000. Last previous edition approved in 2006 as D6575 00(2006
14、).DOI: 10.1520/D6575-14.2For 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.3Available from U.S. Government Print
15、ing Office Superintendent of Documents,732 N. Capitol St., NW, Washington, DC 20401, http:/www.gpo.gov.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1of this length is the bending length of the specimen. The cubeof this quantity mult
16、iplied 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 Stiffness Tester, having the following parts:6.1.1 Horizontal Platform, with a minimum area of 18 by12 in. (457.2 by 304.8 mm) and having a s
17、mooth low-friction,flat surface such as polished metal or plastic.Aleveling 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 the planeof the platform surface.6.1.3 Weight, consisting
18、 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 thespecimens to a moisture equilibrium in the atmosphere fortesting TRMs, that is a t
19、emperature of 70 6 4F (21 6 2C)and relative humidity of 60 6 10 %. See Practice D1776.8. 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
20、to thetransverse (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 direc
21、tiontests and 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. SeePractice D4354.NOTE 1Some TRMs are constructed from severa
22、l component mate-rials and sample 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 allcom
23、ponents together during sample 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
24、are at eye level. Adjustthe platform 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 leadin
25、g edges project beyond the edge 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
26、.9.4 Take four readings from each 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 D5261.10. Calculation10.1 Unless otherwise specified, average the four readingsobtained from all the specimens cut parall
27、el to the machinedirection. Do 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 don
28、e, specify thedirection of bending. 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 Lo/2 (1)where:Lo= length of overhang, cm.Flexural rigidity, G 5 W 3
29、 Lo/2!35 W 3 c3(2)where:W = weight per unit area, mg/cm2.NOTE 2To obtain the weight in mg/cm2, multiply oz/yd2by 3.39.Federal Specification CCC-T-191b gives flexural rigidity in in.-lb. Toconvert in.-lb to mg-cm, multiply by 1.15 106.11. Report11.1 Report the following information:11.2 Report to thr
30、ee significant figures the flexural rigidityof the machine direction 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:Go5 GMDGCD!1/2(3)where:Go= overall flexural rigidity,GMD= machine direct
31、ion flexural rigidity, andGCD= cross-machine flexural rigidity.12. 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 obtain
32、ed by feeling samples for severalranges of geosynthetics of widely 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, andD6575 142that this is about t
33、he limit of reliability of stiffness test results.It also has been found 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 (o
34、r moisture-content if a biodegradable componentis present.)ASTM International takes no position 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 pat
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