1、Designation: D5994 10Standard Test Method forMeasuring Core Thickness of Textured Geomembranes1This standard is issued under the fixed designation D5994; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、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 a procedure to measure the corethickness of textured geomembranes.1.2 This test method does not provide thickne
3、ss values forgeomembranes under variable normal stresses.1.3 The values stated in SI units are to be regarded asstandard. The inch-pound values given in parentheses are forinformation only.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is
4、 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. Referenced Documents2.1 ASTM Standards:2D4354 Practice for Sampling of Geosynthetics for TestingD4439 Terminology for Geosy
5、ntheticsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE2554 Practice for Estimating and Monitoring the Uncer-tainty of Test Results of a Test Method in a SingleLaboratory Using
6、a Control Sample Program3. Terminology3.1 For definitions of other terms relating to geomembranesused in this test method, refer to the Terminology D4439.3.2 Definitions:3.2.1 core thickness, nthe average thickness of a texturedgeomembrane as measured using this particular test method.3.2.2 geomembr
7、ane, nan essentially impermeable geo-synthetic composed of one or more synthetic sheets. D44393.2.3 pressure, nthe force or load per unit area.3.2.4 textured geomembrane, na geomembrane havingone or both surfaces intentionally manufactured with projec-tions or indentations, most commonly for the pur
8、pose ofproviding increased shear strength against adjacent materials.3.2.5 thickness, nthe perpendicular distance between onesurface and its opposite.3.2.6 thickness gauge points, nthe tips of a thicknessgauge which contact the upper and lower geomembranesurfaces, and between which the thickness is
9、measured.4. Summary of Test Method4.1 The core thickness of a textured geomembrane iscalculated as the average value of measurements taken onreplicate specimens of the sample under investigation. Thethickness of each specimen is measured at a specific location asthe distance between two gauge points
10、. The opposing thicknessgauge points are manufactured to a defined geometry, with aspecified force of 0.56 6 0.05 N (2.0 6 0.2 oz) applied alongtheir axis.5. Significance and Use5.1 Thickness is one of the basic index properties used tocontrol and track the quality of many geomembranes. Addi-tionall
11、y, many mechanical properties (for example, tensileyield strength, puncture strength, etc.) can be related to corethickness. Core thickness values may also be required incalculation of some parameters such as diffusion coefficients ortensile stresses.5.2 The measured core thickness of geomembranes m
12、ayvary considerably depending on the pressure applied to thespecimen during measurement. To reduce variation in measure-ments and the chance of unrealistically low values due toexcessively high pressures, a specific gauge point geometryand applied force are prescribed in this test method.5.3 The tes
13、t method is applicable to all commonly availabletextured geomembranes that are deployed as manufacturedgeomembrane sheets.6. Apparatus6.1 Thickness GaugeThe thickness gauge shall be of thedead-weight type capable of measuring to an accuracy of atleast 60.01 mm (0.0004 in.). The gauge shall be constr
14、ucted to1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.10 on Geomem-branes.Current edition approved July 1, 2010. Published September 2010. Originallyapproved in 1996. Last previous edition approved in 2003 as D5
15、99498(2003).DOI: 10.1520/D5994-10.2For 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.1Copyright ASTM Internation
16、al, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.permit application of a specific force of 0.56 6 0.05 N (2.0 60.2 oz). The gauge shall have a base point (or anvil) and afree-moving presser point whose axes are aligned to each other.NOTE 1The geomembrane specim
17、en being measured should be main-tained perpendicular to the axes of the opposing gauge points. Anunderlying support system may be necessary to support large testspecimens.6.2 Thickness Gauge PointsThe gauge points shall bemade of hardened steel. The points shall be tapered at an angleof 60 6 2 to t
18、he horizontal with the tip rounded to a radius of0.8 6 0.1 mm (0.031 6 0.004 in.). Fig. 1 shows the criticaldimensions.NOTE 2The gauge and points can be calibrated using standardthickness blocks. Frequent use and rough use of the gauge can dull thegauge points and cause misalignment, both of which w
19、ill cause incorrectreadings. These problems can be detected by frequent calibration.7. Sampling7.1 SampleFor the sample, take a full width sample ofsufficient length so that the requirements of 7.2 through 7.4.2can be met. Exclude the inner and outer wraps of the roll or anymaterial not representati
20、ve of the sample (see Note 1).7.2 Remove test specimens from the sample in a randomlydistributed pattern across the width. The thickness readingsmust include measurements within 15 cm (6 in.) of both edgesof the geomembrane roll.7.3 Test SpecimensFrom each unit in the sample, removethe specimens so
21、that the edge of the specimen will extendbeyond the edge of the gauge points by 10 mm (0.4 in.) in alldirections. It is recommended to use circular test specimens ofapproximately 75 mm (3 in.) diameter.7.4 Number of SpecimensUnless otherwise agreed upon,as when provided in an applicable material spe
22、cification, takea number of test specimens per sample such that the user mayexpect, at the 95 % probability level, that the test result is notmore than 5 % of the average above or below the true averageof the sample. Determine the number of specimens per sampleas follows:7.4.1 Reliable Estimate of v
23、When there is a reliableestimate of v based upon extensive sample records for similarmaterials tested in the users laboratory as directed in themethod, calculate the required number of specimens as fol-lows:n 5 tv/A!2(1)where:n = number of test specimens (rounded upward to a wholenumber),t = the val
24、ue of Students “t” for one-sided limits (seeTable 1 in Test Method D4354), a 95 % probabilitylevel, and the degrees of freedom associated with theestimate of v,v = reliable estimate of the coefficient of variation ofindividual observations on similar materials in theusers laboratory under conditions
25、 of single-operationprecision, %, andA = 5 % of the average, the value of the allowable varia-tion.7.4.2 No Reliable Estimate of vWhen there is no reliableestimate of v for the users laboratory, Eq 1 should not be useddirectly. Instead, specify the fixed number ten of specimens.The number of specime
26、ns is calculated using v = 9.5 % of theaverage. These values for v are somewhat larger than usuallyfound in practice. When a reliable estimate of v for the userslaboratory becomes available, Eq 1 will usually require fewerthan the fixed number of specimens.FIG. 1 Dead Weight Thickness Measurement De
27、vice for Textured GeomembranesD5994 1028. Conditioning8.1 Bring the specimens to a temperature equilibrium of 216 2C (70 6 4F) and a relative humidity of 60 6 10 %.9. Procedure9.1 Test the conditioned specimens in the standard labora-tory atmosphere specified in 8.1.9.2 With the specified force appl
28、ied to the presser point onthe base point (that is, no specimen present), zero the measur-ing scale or record the initial non-zero reading.9.3 Lift the presser point and insert the test specimen. Whileallowing the presser point to come slowly into contact with thetest specimen, adjust the test speci
29、men to locate the gaugepoints in the “low spots” or “valleys,” in between the projec-tions, or into the indentations, of the textured surface(s) toobtain the local minimum thickness reading. Repeat the aboveso that a total of three measurement readings are obtained foreach specimen. Record only the
30、lowest value of the threereadings to the nearest 0.025 mm or 0.001 in. as the thicknessfor that specimen.9.4 Allow the full dead weight pressure to be applied for 5s, and record the thickness value to the accuracy of the gauge.9.5 Repeat the method for each of the remaining specimens.10. Calculation
31、10.1 Calculate the average thickness of the sample from theindividual specimen results and record to the nearest 0.025 mmor 0.001 in.11. Report11.1 Report the following information for the averagethickness:11.1.1 Project, type of geomembrane tested, and method ofsampling.11.1.2 Name or description o
32、f thickness apparatus used fortesting.11.1.3 Dimensions of the gauge points (if different than thisstandard).11.1.4 Dimensions of the sample and test specimens (ifdifferent than this standard).11.1.5 Loading time interval.11.1.6 Number of specimens.11.1.7 Report the individual specimen thickness mea
33、sure-ments to the nearest 0.025 mm or 0.001 in.11.1.8 Report the average thickness of the individual mea-surements to the nearest 0.025 mm or 0.001 in.11.1.9 Coefficient of variation of the individual measure-ments of the sample, in percent (optional).11.1.10 Any unusual or out-of-standard condition
34、s or obser-vations made during the tests.12. Precision, Bias, and Uncertainty312.1 The precision and bias of this test method and theuncertainty of the test results are based on an interlaboratorystudy of conducted in 2007. Eight laboratories performed theprocedure as recorded in Test Method D5994,
35、testing fivedifferent materials. Every test result represents an individualdetermination. Three separate laboratory-day determinationswere taken in triplicate for each material tested. Each labora-tory utilized one technician and one apparatus. One laboratoryrecorded a single measurement in triplica
36、te for each material.Practice E691 was followed for the design and analysis of thestudy data. The standard units for the core thickness test resultsare 0.001 in. or “mils.” The details are provided in ASTMResearch Report RR:D35-1013.12.1.1 Precision for Test Method D5994:The average test value 51.71
37、 milsThe test range (reported) 35.9 to 67 mils95% repeatability limit (within laboratory) 1.51 mils95% reproducibility limit (between laboratories) 3.29 mils12.1.2 Repeatability Limit (r)Two test results obtainedwithin one laboratory shall be judged not equivalent if theydiffer by more than the “r”
38、value for that material; “r” is theinterval representing the critical difference between two testresults for the same material, obtained by the same operatorusing the same equipment on the same day in the samelaboratory.12.1.2.1 Repeatability limits are listed in Table 1.12.1.3 Reproducibility Limit
39、 (R)Two test results shall bejudged not equivalent if they differ by more than the “R” valuefor that material; “R” is the interval representing the criticaldifference between two test results for the same material,obtained by different operators using different equipment indifferent laboratories.12.
40、1.3.1 Reproducibility limits are listed in Table 1.12.1.4 The terms repeatability limit and reproducibility limitare used as specified in Practice E177.12.2 UncertaintyRepeated measurements made on thesame three sets of ten test specimens on three differentmeasurement events provided a preliminary e
41、stimate of theuncertainty of the test result. The algorithms for these calcu-lations are based on Practice E2554. See Table 2.3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D35-1013.TABLE 1 Core Thickness of Textured Geomembran
42、e using D5994 (mils)Sample AverageARepeatabilityStandard DeviationReproducibilityStandard DeviationRepeatabilityLimitReproducibilityLimitx srsRrR1 59.03 0.60 1.30 1.67 3.652 38.80 0.52 1.00 1.46 2.793 57.54 0.46 0.81 1.28 2.274 38.39 0.60 1.27 1.67 3.565 64.78 0.52 1.49 1.46 4.16AThe average of the
43、laboratories calculated averages.D5994 10312.3 BiasAT the time of the study, there was no acceptedreference material suitable for determining the bias for this testmethod; therefore no statement on bias is being made.12.4 The precision statement was determined through sta-tistical examination of 330
44、 results from eight laboratories onfive materials. These five samples were described as:Sample 1: 60mil Textured HDPE (Blown Film A)Sample 2: 40mil Textured LLDPE (Blown Film A)Sample 3: 60mil One-Side Textured HDPE (Blown Film B)Sample 4: 40mil Textured LLDPE (Blown Film B)Sample 5: 60mil Textured
45、HDPE (Extruded)13. Keywords13.1 geomembrane; geosynthetics; textured geomembrane;thicknessASTM 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
46、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
47、. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to 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 com
48、ments have not received a fair hearing you shouldmake your views known to the ASTM Committee 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
49、 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).TABLE 2 Uncertainty of Core Thickness of TexturedGeomembrane Test Results (mils)Sample AverageARange ofLaboratory UncertaintyStandard DeviationsAverage UncertaintyStandard Deviationx Su1 59.03 0.33 to 0.99 0.602 38.80 0.43 to 0.83
