ASTM_D_4632-D4632M-15.pdf

Designation:D4632/D4632M-15aINTERNATIONALStandard Test Method forGrab Breaking Load and Elongation of GeotextilesThis standard is issued under the fixed designation D4632/D4632M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon(s)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.ScopeD76/D76M Specification for Tensile Testing Machines for1.1 This test method is an index test which provides aTextilesprocedure for determining the breaking load(grab strength)D123 Terminology Relating to Textilesand elongation(grab elongation)of geotextiles using the grabD1776/D1776M Practice for Conditioning and Testing Tex-method.This test method is not suitable for knitted fabrics andtilesalternate test methods should be used.While useful for qualityD2905 Practice for Statements on Number of Specimens forcontrol and acceptance testing for a specific fabric structure,Textiles(Withdrawn 2008)3the results can only be used comparatively between fabricsD4354 Practice for Sampling of Geosynthetics and Rolledwith very similar structures,because each different fabricErosion Control Products(RECPs)for Testingstructure performs in a unique and characteristic manner in thisD4439 Terminology for Geosyntheticstest.The grab test methods does not provide all the informationE177 Practice for Use of the Terms Precision and Bias inneeded for all design applications and other test methodsASTM Test Methodsshould be used.E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method1.2 Procedures for measuring the breaking load and elon-gation by the grab method in both the dry and wet state are3.Terminologyincluded;however,testing is normally done in the dry condi-3.1 Definitions:tion unless specified otherwise in an agreement or specifica-3.1.1 atmosphere for testing geotextiles,n-air maintainedtion.at a relative humidity of 65 5%relative humidity and1.3 The values stated in either SI units or inch-pound unitstemperature of 21 2C 70 4F.are to be regarded separately as standard.The values stated in3.1.2 breaking load,n-the maximum force applied to aeach system may not be exact equivalents;therefore,eachspecimen in a tensile test carried to rupture.system shall be used independently of the other.Combiningvalues from the two systems may result in non-conformance3.1.3 cross-machine direction,n-the direction in the planewith the standard.of the fabric perpendicular to the direction of manufacture.1.4 This standard does not purport to address all of the3.1.4 elongation at break,n-the elongation correspondingsafety concerns,if any,associated with its use.It is theto the breaking load,that is,the maximum load.responsibility of the user of this standard to establish appro-3.1.5 geotextile,n-any permeable textile material usedpriate safety and health practices and determine the applica-with foundation,soil,rock,earth,or any other geotechnicalbility of regulatory limitations prior to use.material,as an integral part of a man-made product,structure,or system.2.Referenced Documents3.1.6 grab test,n-in fabric testing,a tension test in which2.1 ASTM Standards:2only a part of the width of the specimen is gripped in theclamps.3.1.6.1 Discussion-For example,if the specimen width isThis test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechani-101.6 mm 4 in.and the width of the jaw faces 25.4cal Properties.mm 1 in.,the specimen is gripped centrally in the clamps.Current edition approved May 15,2015.Published June 2015.Originally3.1.7 machine direction,n-the direction in the plane of theapproved in 1991.Last previous edition approved in 2015 as D4632/D4632M-15.DOI:10.1520/D4632_D4632M-15A.fabric parallel to the direction of manufacture.2 For 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 on3The last approved version of this historical standard is referenced onthe ASTM website.www.astm.org.Copyright ASTM Intenational,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesD4632/D4632M-15a3.1.8 For definitions of other terms used in this test method,6.Apparatusrefer to Terminology D123 or Terminology D4439.6.1 Tensile Testing Machine,of the constant-rate-of-extension(CRE)or constant-rate-of-traverse(CRT)type with4.Summary of Test Methodautographic recorder conforming to the requirements of Speci-4.1 A continually increasing load is applied longitudinallyfication D76/D76M.to the specimen and the test is carried to rupture.Values for the6.2 Clamps,having all gripping surfaces parallel,flat,andbreaking load and elongation of the test specimen are obtainedcapable of preventing slipping of the specimen during a test.from machine scales or dials,autographic recording charts,orEach clamp shall have one jaw face measuring 25.4 by 50.8interfaced computers.mm 1 by 2 in.,with the longer dimension parallel to thedirection of application of the load.The other jaw face of each5.Significance and Useclamp shall be at least as large as its mate.Each jaw face shall5.1 The grab method is applicable whenever it is desired tobe in line,both with respect to its mate in the same clamp anddetermine the effective strength of the fabric in use,that is,to the corresponding jaw of the other clamp.the strength of the material in a specific width,together withthe additional strength contributed by adjacent material.There7.Sampling and Selectionis no simple relationship between grab tests and strip tests since7.1 Division into Lots and Lot Samples-Divide the materialthe amount of fabric assistance depends on the construction ofinto lots and take a lot sample as directed in Practice D4354.the fabric.It is useful as a quality control or acceptance test.Rolls of fabric are the primary sampling unit.5.2 The procedure in Test Method D4632/D4632M for the7.2 Laboratory Sample-Take for the laboratory sample adetermination of grab strength of geotextiles may be used forswatch extending the width of the fabric and approximatelyacceptance testing of commercial shipments,but caution isI m 39.37 in.along the selvage from each roll in the lotadvised since information about between-laboratory precisionsample.The swatch may be taken from the end portion of a rollis incomplete.Comparative tests as directed in 5.2.1 areprovided there is no evidence that it is distorted or differentadvisable.from other portions of the roll.In cases of dispute,take a5.2.1 In case of a dispute arising from differences inswatch that will exclude fabric from the outer wrap of the rollreported test results when using the procedures in Test Methodor the inner wrap around the core.D4632/D4632M for acceptance testing of commercial7.3 Test Specimens-Cut the number of specimens fromshipments,the purchaser and the manufacturer should conducteach swatch in the laboratory sample determined as directed incomparative tests to determine if there is a statistical biasSection 8.Take no specimens nearer the selvage of fabric edgebetween their laboratories.Competent statistical assistance isthan V2o of the fabric width or 150 mm 6 in.,whichever is therecommended for the investigation of bias.As a minimum,thesmaller.Cut rectangular specimens 101.6 by 203.2two parties should take a group of test specimens that are asmm 4 by 8 in.Cut the specimens to be used for grab tests inhomogeneous as possible and which are from a lot of materialthe machine direction with the longer dimension parallel to theof the type in question.The test specimens should then bemachine direction and the specimens to be used for grab testsrandomly assigned in equal numbers to each laboratory forin the cross-machine direction with the longer dimensiontesting.The average results from the two laboratories should beparallel to the cross-machine direction.Locate each group ofcompared using the appropriate Students t-test and an accept-specimens along a diagonal line on the swatch so that eachable probability level chosen by the two parties before testingspecimen will contain different warp ends and filling picks.is begun.If a bias is found,either its cause must be found andDraw a line 37 mm 1.5 in.from the edge of the specimencorrected or the purchaser and the manufacturer must agree torunning its full length.For woven and reinforced nonwoveninterpret future test results in the light of the known bias.fabrics,this line must be accurately parallel to the lengthwise5.3 Most geotextile fabrics can be tested by this test methodyarns in the specimen.Some modification of clamping techniques may be necessaryfor a given fabric,depending upon its structure.Special8.Number of Specimensadaptation may be necessary with strong fabrics,or fabrics8.1 Unless otherwise agreed upon as when provided in anmade from glass fibers,to prevent them from slipping in theapplicable material specification,take a number of test speci-clamps or being damaged as a result of being gripped in themens per swatch in the laboratory sample such that the userclamps,such as cushioning the clamp or boarding the specimenmay expect at the 95%probability level that the test result iswithin the clamp.no more than 5%above the true average for each swatch in the5.4 This test method is applicable for testing fabrics eitherlaboratory sample for each the machine and cross-machinedry or wet.It may be used with constant-rate-of-traverse(CRT)direction,respectively.or constant-rate-of-extension(CRE)type tension machines.8.1.1 Reliable Estimate of v-When there is a reliableHowever,there may be no overall correlation between theestimate of v based upon extensive past records for similarresults obtained with the CRT machine and the CRE machine.materials tested in the users laboratory as directed in theConsequently,these two tension testers cannot be used inter-method,calculate the required number of specimens using Eqchangeably.In case of controversy,the CRE machine shall1,as follows:prevail.n=(v/A)2(1)D4632/D4632M-15awhere:9.2 Specimens to be tested in the wet condition shall ben number of test specimens(rounded upward to a wholeimmersed in water maintained at a temperature of 21+2Cnumber).70 4F.The time of immersion must be sufficient tov=reliable estimate of the coefficient of variation of indi-wet-out the specimens thoroughly,as indicated by no signifi-vidual observations on similar materials in the userscant change in strength or elongation following a longer periodlaboratory under conditions of single-operatorof immersion,and at least 2 min.To obtain thorough wetting.precision,%it may be necessary or advisable to add not more than 0.05%the value of Students t for one-sided limits(see Tableof a nonionic neutral wetting agent to the water.1),a 95 probability level,and the degrees of freedomassociated with the estimate of v,and10.ProcedureA5.0%of the average,the value of the allowable10.1 Test the conditioned specimens in the standard atmo-variation.sphere for testing in accordance with Section 9.8.1.2 No Reliable Estimate of v-When there is no reliable10.2 Set the distance between the clamps at the start of theestimate of y for the users laboratory.Eq I should not be useddirectly.Instead,specify the fixed number of 10 specimens fortest at 75 1 mm 3+0.05 in.Select the load range of thetesting machine such that the maximum load occurs betweenthe machine direction tests and 10 specimens for the cross-machine direction tests.The number of specimens is calculated10 and 90 of full-scale load.Set the machine to operate at ausing v=9.5 of the average for both machine direction andspeed of30010mm/min120.5in./min.cross-machine direction.These values for v are somewhat10.3 Secure the specimen in the clamps of the testinglarger than usually found in practice.When a reliable estimatemachine,taking care that the long dimension is as nearly asof v for the users laboratory becomes available,Eg I willpossible parallel to the direction of application of the load.Beusually require fewer than the fixed number of specimens.sure that the tension in the specimen is uniform across theclamped width.Insert the specimen in the clamps so that9.Conditioningapproximately the same length of fabric extends beyond the9.1 Bring the specimens to moisture equilibrium in thejaw at each end.Locate the jaws centrally in the widthwiseatmosphere for testing geotextiles.Equilibrium is considered todirection by having the line which was drawn 37 mm 1.5 in.have been reached when the increase in mass of the specimenfrom the edge of the specimen run adjacent to the side of thein successive weighings made at intervals of not less than 2 hupper and lower front jaws which are nearest this edge.Thisdoes not exceed 0.1 of the mass of the specimen.In generalensures that the same lengthwise yarns are gripped in bothpractice,the industry approaches equilibrium from the asclamps.receivedside.10.4 If a specimen slips in the jaws,breaks at the edge of orin the jaws,or if for any reason attributed to a faulty operationNorE 1-It is recognized that in practice geotextile materials arefrequently not weighed to determine when moisture equilibrium has beenthe result falls markedly below the average for the set ofreached.While such a procedure cannot be accepted in cases of dispute,specimens,discard the result and take another specimen.it may be sufficient in routine testing to expose the material to the standardContinue this procedure until the required number of accept-atmosphere for testing for a reasonable period of time before theable breaks have been obtained.specimens are tested.A time of at least 24 h has been found acceptable inmost cases.However,certain fibers may exhibit slow moisture equaliza-NorE 2-The decision to discard a break shall be based on observationtion rates from the as receivedwet side.When this is known,aof the specimen during the test and upon the inherent variability of thepreconditioning cycle,as described in Practice D1776/D1776M.may befabric.In the absence of other criteria for rejecting a so-called jaw break.agreed upon between contractual parties.any break occurring within 5 mm in.of the jaws which results in avalue below 80%of the average of all the other breaks shall be discarded.No other break shall be discarded unless it is known to be faulty.TABLE 1 Values of Students t for One-Sided LimitsNorE 3-It is difficult to determine the precise reason for breakage ofand the 95%Probabilitytest specimens near the edge of the jaws.If breaks are caused by damageto the specimen by the jaws,then the results should be discarded.If.One-dfOne-One-SidedSidedsidedhowever,they are merely due to randomly distributed weak places inspecimens,the results should be considered perfectly legitimate.In some6.314111.796221.717cases,breaks may be caused by a concentration of stress in the area2.9201.782241.71132.353131.771261.706adjacent to the jaws.If this occurs,the specimen is prevented from42.132141.761281.701contracting in width as the load is applied.In such cases,a break near the52.0151.7531.697edge of the jaws is inevitable and shall be accepted as a characteristic of61.943161.746401.684the geotextile when tested by this test method.71.8951.740501.67681.860181.734601.67110.5 Start the tensile testing machine and the area measur-91.833191.7291201.658ing device,if used,and continue running the test to rupture.101.812201.7251.645Stop the machine and reset to the initial gage position.RecordA Values in this table were calculated using Hewlett Packard HP 67/97 Usersand report the test results for each direction separately.Library Programs 03848D,One-Sided and Two-Sided Critical Values of Students f and 00350D,Improved Normal and Inverse Distribution.For values at10.6 If fabric manifests slippage in the jaws,the jaw faces,other than the 95%probability level,see published tables of critical values ofbut not the jaw dimensions,may be modified.If a modificationStudents t in any standard statistical text.Further use of this table is defined inPractice D2905.is used.the method of modification should be stated in thereport.D4632/D4632M-15a10.7 Unless otherwise specified,measure the elongation of12.1.8 Type of padding used in jaws,modification ofthe fabric at any stated load by means of a suitable autographicspecimen gripped in the jaws,or modification of jaw faces,ifrecording device,at the same time the breaking strength isused.determined.Measure the elongation from the point where the12.1.9 Any modifications of sample specimens ascurve leaves the zero loading axis to a point of correspondingmanufactured,or test method as described.force in millimetres inches.13.Precision and Bias11.Calculation13.1 Precision-The precision of this test method is based11.1 Breaking Load-Calculate the breaking load by aver-on an interlaboratory study of D4632/D4632M,Standard Testaging the value of breaking load for all accepted specimenMethod for Grab Breaking Load and Elongation ofresults.The breaking load shall be determined separately forGeotextiles,conducted in 2013.Ten laboratories tested a totalthe machine direction specimens and cross-machine directionof four different geotextile samples for elongation and tensilespecimens.strength at rupture.Every test result represents an individual11.2 Apparent Elongation-Calculate the apparent elonga-determination.All labs were asked to report triplicate testtion at the breaking load or at other specified loads byresults for each material tested.Practice E691 was followed foraveraging the values of apparent elongation for all acceptedthe design and analysis of the data;the details are given inspecimen results.The apparent elongation shall be determinedASTM Research Report No.RR:D35-1021.separately for the machine direction specimens and cross-13.1.1 Repeatability Limit(r)-Two test results obtainedmachine direction specimens and expressed as the percentagewithin one laboratory shall be judged not equivalent if theyincrease in length,based upon the initial nominal gage lengthdiffer by more than the r value for that material;r is theof the specimen.Report this as the apparent elongation.interval representing the critical difference between two testresults for the same material,obtained by the same operatorNoTE 4-The observed elongation calculated as a percentage of theusing the same equipment on the same day in the sameinitial nominal gage length of the specimen should be referred to asapparent elongation.Because the actual length of fabric stretched islaboratory.usually somewhat greater than this initial length due to pull-out of fabric13.1.1.1 Repeatability limits are listed in Tables 2 and 3.from between the jaws,elongation calculated on initial length may be13.1.2 Reproducibility limit(R)-Two test results shall besomewhat in error,depending upon the amount of this pull-out.judged not equivalent if they differ by more than the Rvalue12.Reportfor that material;R is the interval representing the criticaldifference between two test results for the same material,12.1 Report the following information:obtained by different operators using different equipment in12.1.1 State that the tests were performed as directed in Testdifferent laboratories.Method D4632/D4632M.Describe the material(s)or prod-13.1.2.1 Reproducibility limits are listed in Tables 2 and 3.uct(s)sampled and the method of sampling used.13.1.3 The above terms(repeatability limit and reproduc-12.1.2 The average grab breaking load for specimens cut inibility limit)are used as specified in Practice E177.each direction,for all specimens giving acceptable breaks.13.1.4 Any judgment in accordance with statements 13.1.112.1.3 The average grab percent apparent elongation ofand 13.1.2 would have an approximate 95%probability ofspecimens cut in each direction,for all specimens givingbeing correct.acceptable breaks,if required.Identify this as apparentbreaking elongation,or apparent elongation at x Ib load,as13.2 Bias-At the time of the study,there was no acceptedreference material suitable for determining the bias for this testrequired by the test specifications.12.1.4 Number of specimens tested in each direction.method,therefore no statement on bias is being made.12.1.5 Condition of specimens(wet or dry).12.1.6 Type of testing machine used.12.1.7 Maximum load obtainable in the range used for4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D35-1021.Contact ASTM Customertesting.Service at service astm.org.TABLE 2 Maximum Elongation at Rupture(%)RepeatabilityReproducibilityMaterialAverageStandardStandardRepeatability LimitReproducibility LimitDeviationDeviationSSRrWoven Slit Tape25.240.855.372.3915.02Stabilization GeotextileHeavy Weight79.201.7212.394.8134.70Nonwoven GeotextileLight Weight79.032.666.007.4416.79Nonwoven GeotextileWoven Mono/Slit Tape22.430.844.922.3513.78Reinforcement Geotextile The average of the laboratories calculated averages.D4632/D4632M-15aTABLE 3 Maximum Tensile at Rupture(lbf)RepeatabilityReproducibilityMaterialAverageStandardStandardRepeatability LimitReproducibility LimitDeviationDeviationS,SRrRWoven Slit Tape168.237.4317.3520.8148.57Stabilization GeotextileLight Weight425.2720.8126.2558.2873.49Nonwoven GeotextileHeavy Weight131.5110.2710.2728.7528.75Nonwoven GeotextileWoven Mono/Slit Tape377.0411.1022.7931.0863.80Reinforcement Geotextile The average of the laboratories calculated averages.13.3 The precision statement was determined through sta-13.4 To judge the equivalency of two test results,it ististical examination of 240 reported results,from ten recommended to choose the material closest in characteristicslaboratories,on four materials.These four materials wereto the test material.identified as the following:Woven Slit Tape Stabilization GeotextileLight Weight Nonwoven GeotextileHeavy Weight Nonwoven GeotextileWoven Mono/Slit Tape Reinforcement GeotextileASTM 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 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.Your comments are invited either for revision of this standard or for additional standardsand should be 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