1、Designation: D5994/D5994M 10 (Reapproved 2015)1Standard Test Method forMeasuring Core Thickness of Textured Geomembranes1This standard is issued under the fixed designation D5994/D5994M; the number immediately following the designation indicates theyear of original adoption or, in the case of revisi
2、on, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEDesignation was changed to dual and units information was corrected editorially in June 2015.1. Scope1.1 This
3、 test method covers a procedure to measure the corethickness of textured geomembranes.1.2 This test method does not provide thickness values forgeomembranes under variable normal stresses.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The value
4、s stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with it
5、s 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. Referenced Documents2.1 ASTM Standards:2D4354 Practice for Sampling of Geosynthetics and RolledErosion Control
6、Products(RECPs) for TestingD4439 Terminology for GeosyntheticsE177 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
7、 Results of a Test Method Using ControlChart Techniques3. 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 partic
8、ular test method.3.2.2 geomembrane, nan essentially impermeable geosyn-thetic 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 indentat
9、ions, most commonly for the purpose 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
10、between which the thickness is 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 di
11、stance between two gauge points. 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 ma
12、ny geomembranes.Additionally, 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
13、thickness of geomembranes mayvary considerably depending on the pressure applied to the1This 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 May 1, 2015. Published June 2015.
14、 Originallyapproved in 1996. Last previous edition approved in 2010 as D599410. DOI:10.1520/D5994_D5994M-10R15E01.2For 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 th
15、e standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1specimen during measurement. To reduce variation in measure-ments and the chance of unrealistically low values due toexcessively high
16、 pressures, a specific gauge point geometryand applied force are prescribed in this test method.5.3 The test 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-
17、weight type capable of measuring to an accuracy of atleast 60.01 mm 0.0004 in. The gauge shall be constructed topermit 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 1
18、The geomembrane specimen being measured should bemaintained 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
19、 angleof 60 6 2 to the 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
20、, both of which will 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
21、 not representative 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, removeth
22、e specimens so 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 m
23、aterial specification, 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 Es
24、timate of vWhen 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),
25、t = the value of Students “t” for one-sided limits (see Table1 in Practice D4354), a 95 % probability level, and thedegrees of freedom associated with the estimate of v,FIG. 1 Dead Weight Thickness Measurement Device for Textured GeomembranesD5994/D5994M 10 (2015)12v = reliable estimate of the coeff
26、icient of variation of indi-vidual observations on similar materials in the userslaboratory under conditions of single-operationprecision, %, andA = 5 % of the average, the value of the allowable variation.7.4.2 No Reliable Estimate of vWhen there is no reliableestimate of v for the users laboratory
27、, Eq 1 should not be useddirectly. Instead, specify the fixed number ten of specimens.The number of specimens 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
28、 1 will usually require fewerthan the fixed number of specimens.8. 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 t
29、he specified force applied 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
30、, adjust the test specimen to locate the gaugepoints in the “low spots” or “valleys,” in between theprojections, or into the indentations, of the textured surface(s)to obtain the local minimum thickness reading. Repeat theabove so that a total of three measurement readings areobtained for each speci
31、men. Record only the lowest value ofthe three readings to the nearest 0.025 mm or 0.001 in. as thethickness for that specimen.9.4 Allow the full dead weight pressure to be applied for 5 s,and record the thickness value to the accuracy of the gauge.9.5 Repeat the method for each of the remaining spec
32、imens.10. Calculation10.1 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
33、Name or description of 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 s
34、pecimen thickness measure-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-
35、of-standard conditions 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 i
36、n Test Method D5994/D5994M, testingfive different materials. Every test result represents an indi-vidual determination. Three separate laboratory-day determi-nations were taken in triplicate for each material tested. Eachlaboratory utilized one technician and one apparatus. Onelaboratory recorded a
37、single measurement in triplicate for eachmaterial. Practice E691 was followed for the design andanalysis of the study data. The standard units for the corethickness test results are 0.001 in. or “mils.” The details areprovided in ASTM Research Report RR:D35-1013.12.1.1 Precision for Test Method D599
38、4/D5994M:The average test value 51.71 milsThe test range (reported) 35.9 to 67 mils95% repeatability limit (within laboratory) 1.51 mils95% reproducibility limit (betweenlaboratories)3.29 mils12.1.2 Repeatability Limit (r)Two test results obtainedwithin one laboratory shall be judged not equivalent
39、if theydiffer by more than the “r” 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 T
40、able 1.12.1.3 Reproducibility Limit (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 equ
41、ipment indifferent laboratories.12.1.3.1 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 differentmeasurem
42、ent events provided a preliminary estimate of theuncertainty of the test result. The algorithms for these calcu-lations are based on Practice E2554. See Table 2.12.3 BiasAT the time of the study, there was no acceptedreference material suitable for determining the bias for this testmethod; therefore
43、 no statement on bias is being made.3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D35-1013.D5994/D5994M 10 (2015)1312.4 The precision statement was determined through sta-tistical examination of 330 results from eight laborato
44、ries 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 HDPE (Extruded)13. Keywords1
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48、ir 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 multiple copies) of this st
49、andard 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 Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 1 Core Thickness of Textured Geomembrane using D5994/D5994M (mils)Sample AverageARepeatabilityStandard DeviationReproducibilityStandard DeviationRepeatability
