1、Designation: D6575 14aStandard 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, t
2、he 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 s
4、tandard.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. Refe
5、renced 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 Geosynthetics
6、D5261 Test Method for Measuring Mass per Unit Area ofGeotextilesE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 Federal Standards:3CCC-T-191b Textile Test Methods No. 5206.23.
7、 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 geosynthetic stiffness as shown by theway in which a geosynthetic bends under its own weight. Itreflects the stiffness of a geosynthe
8、tic 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-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,
9、 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.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
10、.4 DiscussionThe methods measure the bendinglength. Flexural rigidity is calculated directly by multiplyingthe 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 th
11、is 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 designated as Test MethodD1388).4.2 The cantilever test method may not be suitable fortesting products that are very limp or have
12、 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 that its end projects from the edge of a1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is th
13、e direct responsibility of Subcommittee D35.05 on Geosyn-thetic Erosion Control.Current edition approved Aug. 1, 2014. Published September 2014. Originallyapproved in 2000. Last previous edition approved in 2014 as D6575 14. DOI:10.1520/D6575-14A.2For referenced ASTM standards, visit the ASTM websit
14、e, 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 Printing Office Superintendent of Documents,732 N. Capitol St., NW, Washington, DC
15、 20401, http:/www.gpo.gov.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1horizontal 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
16、 tip to the edge of theplatform 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 Canti
17、leverTest.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 smooth low-friction,flat surface such as polished metal or plastic.Aleveling bubbleshall be incorporated in the platform, or be availa
18、ble 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 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 leng
19、th 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 temperature of 70 6 4F (21 6 2C)and relative humidity of 60 6 10 %. See Practice D1776.8. Selection and Preparation of Specimens8.1 Cu
20、t 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 thetransverse (or cross-machine) direction. If the geosynthetic isnot uniform or a higher degree of precision is required, moremay
21、 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 and cut the cross-machine direction specimens so thatseparate cross-machine direction yarns/filaments are containedin each.
22、 Avoid selvages, end pieces, and creased or foldedplaces, and handle the specimens as little as possible. SeePractice D4354.NOTE 1Some TRMs are constructed from several component mate-rials and sample preparation must be performed in such a way as tomaintain the structural integrity of the product.
23、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 preparation. The method of cuttingthe specimen should be included in the report.9. Procedure9.1 Make t
24、ests 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 platform so that it is horizontal as indicated by the levelingbubble.9.3 Place a specimen on the platform
25、 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 of theplatform. With the eye in a position so that the two inclinedlines of the tendency to twist, ta
26、ke 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 each specimen, with each sideup, first at one end and then the other.9.5 Determine the mass per unit are
27、a of the geosyntheticaccording to Test Method D5261.10. Calculation10.1 Unless otherwise specified, average the four readingsobtained from all the specimens cut parallel to the machinedirection. Do the same for those cut parallel to the cross-machine direction. In some cases it may be of interest to
28、differentiate 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 bending. Call these averages the “length ofoverhang,” and express them in centimetres. Calculate thebendin
29、g 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 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 Specifi
30、cation 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 three significant figures the flexural rigidityof the machine direction and cross-machine direction sepa-rately. If an overall average f
31、igure 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 direction flexural rigidity, andGCD= cross-machine flexural rigidity.12. Precision and Bias412.1 PrecisionThe precision of this test method
32、 is basedon an interlaboratory study of Test Method D6575, conducted4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D35-1019. ContactASTM CustomerService at serviceastm.org.D6575 14a2in 2013. Five laboratories participated in th
33、is study. Each of thelabs reported three replicate test results for three different typesof mats. Every test result reported represents an individualdetermination. Except for the use of only five laboratories,Practice E691 was followed for the design and analysis of thedata; the details are given in
34、 ASTM Research Report No.RR:D35-1019.12.1.1 Repeatability (r)The difference between repetitiveresults obtained by the same operator in a given laboratoryapplying the same test method with the same apparatus underconstant operating conditions on identical test material withinshort intervals of time w
35、ould in the long run, in the normal andcorrect operation of the test method, exceed the followingvalues only in one case in 20.12.1.1.1 Repeatability can be interpreted as the maximumdifference between two results, obtained under repeatabilityconditions, that is accepted as plausible due to random c
36、ausesunder normal and correct operation of the test method.12.1.1.2 Repeatability limits are listed in Tables 1 and 2.12.1.2 Reproducibility (R)The difference between twosingle and independent results obtained by different operatorsapplying the same test method in different laboratories usingdiffere
37、nt apparatus on identical test material would, in the longrun, in the normal 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 maximumdifference between two results, obtained under reproducibilityconditions,
38、 that is accepted as plausible due to random causesunder normal and correct operation of the test method.12.1.2.2 Estimated reproducibility limits are listed in Tables1 and 2.12.1.3 The above terms (repeatability limit and reproduc-ibility limit) are used as specified in Practice E177.12.1.4 Any jud
39、gment in accordance with statements 12.1.1and 12.1.2 would normally have an approximate 95 % prob-ability of being correct, however the precision statistics ob-tained in this ILS must not be treated as exact mathematicalquantities which are applicable to all circumstances and uses.The limited number
40、 of materials tested and laboratories report-ing results guarantees that there will be times when differencesgreater than predicted by the ILS results will arise, sometimeswith considerably greater or smaller frequency than the 95 %probability limit would imply. The repeatability limit and thereprod
41、ucibility limit should be considered as general guides,and the associated probability of 95 % as only a roughindicator of what can be expected.12.2 BiasAt the time of the study, there was no acceptedreference material suitable for determining the bias for this testmethod, therefore no statement on b
42、ias is being made.12.3 The precision statement was determined through sta-tistical examination of 90 results, from five laboratories, onthree materials.12.3.1 To judge the equivalency of two test results, it isrecommended to choose the mat material closest in character-istics to the test material.TA
43、BLE 1 StiffnessMachine Direction (mg-cm)MaterialAverageARepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitx SrSRrRDouble Net Blanket 17047 3833 9705 10732 27173Double Net TRM #1 47758 14032 27718 39290 77610Double Net TRM #2 30694 11958 15501 33483 4
44、3402AThe average of the laboratories calculated averages.D6575 14a3ASTM 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
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48、is 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). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood
49、Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 2 StiffnessCross-Machine Direction (mg-cm)MaterialAverageARepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitx SrSRrRDouble Net Blanket 18808 2835 7513 7937 21036Double Net TRM #1 30226 12208 18072 34182 50601Double Net TRM #2 25720 9963 13458 27897 37683AThe average of the laboratories calculated averages.D6575 14a4
