1、Designation: D5993 99 (Reapproved 2009)Standard Test Method forMeasuring Mass Per Unit of Geosynthetic Clay Liners1This standard is issued under the fixed designation D5993; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、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 laboratory determination ofthe mass per unit area of a sample of a geosynthetic clay li
3、ner(GCL). The dry mass of the clay can be found by simplysubtracting the manufacturers reported nominal mass of thegeosynthetic component(s) from the total mass of the dry GCL.The moisture content of the GCL can also be determined bysubtracting the initial total mass of the GCLfrom the total massof
4、the dry GCL.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 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 es
5、tablish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. See Section 7 forspecific precautionary statements.2. Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD2216 Test Methods for Laboratory Determination
6、 of Wa-ter (Moisture) Content of Soil and Rock by MassD4354 Practice for Sampling of Geosynthetics for TestingD4439 Terminology for GeosyntheticsD4643 Test Method for Determination of Water (Moisture)Content of Soil by Microwave Oven HeatingD4753 Guide for Evaluating, Selecting, and SpecifyingBalanc
7、es and Standard Masses for Use in Soil, Rock, andConstruction Materials TestingD5261 Test Method for Measuring Mass per Unit Area ofGeotextilesE145 Specification for Gravity-Convection and Forced-Ventilation OvensE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Te
8、st Method3. Terminology3.1 Definitions:3.1.1 geosynthetic, na planar product manufactured frompolymeric material used with soil, rock, earth, or other geo-technical engineering related material as an integral part of aman-made project, structure, or system. D44393.1.2 geosynthetic clay liner, na man
9、ufactured hydraulicbarrier consisting of clay bonded to a layer or layers ofgeosynthetic material(s). (Currently being balloted under D35Committee on Terminology.)3.1.3 moisture content, nthat part of the mass of ageosynthetic clay liner that is absorbed water, compared to themass of dry clay.3.1.4
10、oven-dried, adjthe condition of a material that hasbeen heated under prescribed conditions of temperature andhumidity until there is no further significant change in its mass.D1234. Summary of Test Method4.1 The mass per unit area is determined by weighing(oven-dried) specimens of known initial size
11、 after drying in anoven over a sufficient time period to remove the moisture fromthe GCL.4.2 The mass per unit area of the clay component of theGCL can be estimated by subtracting the manufacturersreported nominal mass per unit area of the synthetic compo-nent(s) from the total GCL mass per unit are
12、a.NOTE 1The supplier of the geosynthetic clay liner must be able toverify that the actual mass/unit area of the synthetic component(s) iswithin 610 % of the reported nominal value. A more accurate estimationof the actual dry clay mass per unit area could be obtained by using theactual average value
13、for the synthetic component(s) (as obtained from themanufacturer for the actual lots used to make the GCL) rather than thenominal value.1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.04 on Geosyn-thetic Clay Line
14、rs.Current edition approved Nov. 1, 2009. Published January 2010. Originallyapproved in 1996. Last previous edition approved in 2004 as D5993 99(04). DOI:10.1520/D5993-99R09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For
15、Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.3 The moisture content of the GCL can be estimated withthis test metho
16、d.5. Significance and Use5.1 This test method is used to determine if the GCLmaterial meets specifications for mass per unit area at 0 %moisture content, by oven-drying. It can be used as an indextest for quality control or quality assurance to determinespecimen conformance.6. Apparatus6.1 Drying Ov
17、enThermostatically-controlled, preferablyof the forced-draft type, meeting the requirements of Specifi-cation E145 and capable of maintaining a uniform temperatureof 110C 6 5C throughout the drying chamber.6.2 Microwave OvenA microwave oven, preferably witha vented chamber, is suitable. The required
18、 size and powerrating of the oven is dependent on its intended use. Ovens withvariable power controls and input power ratings of about 700W have been found to be adequate for this use. Variable powercontrols are important and reduce the potential for over heatingthe test specimen.NOTE 2Microwave ove
19、ns equipped with built-in scales and computercontrols have been developed for use in drying soils. Their use iscompatible with this test method.6.3 BalancesAll balances must meet the requirements ofSpecification D4753 and this section. A Class GP1 balance of0.01 g readability is required for samples
20、 having a mass of upto 200 g (excluding mass of sample container) and a Class GP2balance of 0.1 g readability is required for samples having amass over 200 g.6.4 Sample ContainersSuitable containers made of mate-rial resistant to corrosion and change in mass upon repeatedheating, cooling, exposure t
21、o materials of varying pH, andcleaning. Microwave sample containers should be microwavesafe.6.5 DesiccatorA desiccator cabinet or large desiccator jarof suitable size containing indicator silica gel. It is preferable touse a desiccant that changes color to indicate it needs recon-stitution.6.6 Conta
22、iner Handling ApparatusGloves, tongs, or suit-able holder for moving and handling hot containers afterdrying.6.7 Die, of known dimensions.6.8 Miscellaneous, knives, spatulas, scoops, quarteringcloth, sample splitters, and so forth, as required.7. Hazards/Precautions7.1 Handle hot containers with a c
23、ontainer holder.7.2 Safety precautions supplied by the manufacturer of themicrowave oven should be observed.7.3 Do not use metallic containers in a microwave oven (ifused).8. Test Specimens8.1 The sample received at the testing laboratory should bein satisfactory condition and representative of the
24、productmanufactured or delivered to a site, or both.8.2 A sample of a GCL should be cut into specimens in alaboratory using a die or sharp razor blade or razor knife.8.3 The minimum size of the die or template for cuttingspecimens is 0.01 m2(for example, 10 by 10 cm).NOTE 3The use of small specimens
25、 are not recommended due to thepotential for edge loss of clay, which may create problems with accuracyand reproducibility.8.4 Test specimens taken from the laboratory sample shouldbe free from imperfections or other areas not representative ofthe material samples (such as dirt or labels).8.5 Cuttin
26、g of the laboratory specimens with a die or razormay contaminate the work area, die, or razor with particles ofclay or geosynthetic material. The work area should be cleanedbefore cutting the specimen. Therefore, all excess or wastematerial should be cleaned away from the die and cutting areabefore
27、removal of the specimen. The specimen, material on thedie, and cutting area should be placed into a tared container.Wiping of the area should be performed with a nonclingingcloth or brush.8.6 The loss of clay during the specimen cutting processcould have a significant impact to the accuracy of this
28、testmethod. The technician performing this test method shouldpractice cutting test specimens from the laboratory sample untilconfidence is gained that a specimen can be cut withoutsignificant loss of clay.8.6.1 The technician may choose to wet the perimeter of theGCL in an effort to bind the clay pa
29、rticles together and therebyreduce the possibility of clay granule loss during the cuttingprocess. If the sample is wetted, the technician should try tolimit the amount of clay that will attach itself to the die, cuttingboard, template, or cutting instrument, or combination thereof.However, if the t
30、echnician attempting to determine the mois-ture content of the GCL, other cutting methods should be usedthat do not require the addition of water.8.6.2 If a die is used to cut the specimen, loss of clay can bereduced by leaving the die in place and removing all theremaining sample outside the edge o
31、f the die. This includesbrushing the cutting board clean. All material found within theedge of the die could then be placed in the sample containers.8.6.3 Any waste clay left on the cutting board and die orrazor for which the technician cannot determine if the claycame from the individual specimen o
32、r the original sampleshould be collected and weighed. It should be assumed thewaste clay is edge loss from the individual specimen and theoriginal sample. One half the weight of the waste clay shouldbe added to the test specimen container and the other one-halfdiscarded.8.7 The number of test specim
33、ens should be a minimum offive, cut such that they are representative of the entire rollwidth.9. Conditioning9.1 Bring the test specimens to moisture equilibrium in theatmosphere for testing GCLs. Equilibrium is considered tohave been reached when the increase in mass of the testspecimen in successi
34、ve weighing, made at intervals of not lessthan 2 h, does not exceed 0.1 % of the previous mass of the testD5993 99 (2009)2specimen. In general practice, the industry assumes equilib-rium conditions exist in the “as-received” state.10. Procedure (Assuming Moisture Present)10.1 Using the die, or templ
35、ate and razor, and other neces-sary apparatus, carefully cut the laboratory sample intofive 0.01-m2test specimens. The five specimens should berandomly selected from locations on the sample, but should bedistributed across the sample.Any waste clay (including on thedie or razor) should be collected
36、from each individual speci-men and divided in half. One half of the waste clay should beadded to the test specimen container and the other one-halfdiscarded.10.2 The container to be used should be oven dried thor-oughly and subsequently placed into a desiccator until readyfor use so that the tare we
37、ight of the container will be recorded.10.3 Determine and record the tare of the specimen con-tainer.10.4 Select representative test specimens.10.5 Place the test specimen in the individual container.Determine the mass of the container and GCL specimen asdelivered using a balance selected on the bas
38、is of the samplemass. Record the value of the GCL specimen (Mi).NOTE 4To prevent mixing of samples and yielding of incorrectresults, all containers should be numbered and the container numbers shallbe recorded on the laboratory data sheets.10.6 Place the container with the GCL specimen in thedrying
39、oven. Dry the GCL specimen to a constant mass.Maintain the drying oven at 110 6 5C unless otherwisespecified. The time required to obtain constant mass will varydepending on the type of material, size of sample, oven typeand capacity, and other factors. The influence of these factorsgenerally can be
40、 established by good judgment, experiencewith the materials being tested, and the apparatus being used.NOTE 5In most cases, drying a test sample overnight (about 12 to 16h) is sufficient for conventional ovens. In cases where there is doubtconcerning the adequacy of drying, drying should be continue
41、d until thechange in mass after two successive periods (greater than 1 h) of dryingis less than 0.1 %.NOTE 6If a microwave oven is used to dry the test specimen(s), theuser of this test method should follow the drying procedures as stated inTest Method D4643. It is also recommended that the total ma
42、ss of the testspecimen(s) be a minimum of 100 g.NOTE 7Since some dry materials may absorb moisture from moistsamples, dried samples should be removed before placing moist samplesin the same oven. However, this would not be applicable if the previouslydried specimens will remain in the drying oven fo
43、r an additional timeperiod of about 16 h.10.7 After the material has dried to constant mass, removethe container from the oven (and replace the lid if used).Allowthe material and container to cool to room temperature in adesiccation unit or until the container can be handled comfort-ably with bare h
44、ands and the operation of the balance will notbe affected by convection currents or its being heated, or both.Determine the mass of the container and oven-dried materialusing the same balance as used previously. Subtract the tare ofthe container from the mass of the sample to determine thesamples co
45、nstant dry mass. Record this value (MGCL).11. Calculation11.1 Calculate the mass per unit area of each of thespecimens as follows:mGCL5 MGCL/A (1)where:mGCL= mass per unit area of the dried GCL productrounded to the nearest 0.1 g/m2,MGCL= the dried mass of GCL specimen measured to thenearest 0.01 g,
46、= (oven-dried specimen + container mass) (taremass of container), andA = area of the specimen, m2(0.01 m2, if prepared inaccordance with 10.1).11.2 The mass per unit area of the clay component of theGCL can be estimated as follows:mclay5 mGCL2 ms(2)where:mclay= mass per unit area of dry clay compone
47、nt roundedto the nearest 0.1 g/m2, andms= nominal mass per unit area of GCL syntheticcomponent(s), g/m2, as provided by manufacturer(see 4.2, Note 1).11.3 The percent initial moisture content of the clay com-ponent of the GCL can be estimated as follows:wclay5Mi/A! 2 mGCLmclayx 100 (3)where:wclay= i
48、nitial moisture content of the clay component ofthe GCL, percent, rounded to the nearest 0.1 %,andMi= initial mass of GCL specimen.11.4 Calculate the average of the mass per unit area results(and moisture content results, if desired) for the test specimens.NOTE 8Caution: The dried mass/unit area may
49、 include the presenceof adhesives or other additives. Consult the GCL manufacturer foradditional information.12. Report12.1 Report the following information on mass per unit areaof GCLs:12.1.1 Sample identification (for example, sample number,roll number, or other traceable identifier),12.1.2 Type of GCL tested, method used for cutting speci-mens, sample size, specimen size and shape, and number oftest specimens used,12.1.3 The assumed mass of the synthetic component(s)(mcc) (for example, geotextile) and source of information (thatis, manufacturers specif
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