1、Designation: D5993 14Standard 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 of last revision.
2、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 liner(GCL). The test
3、 method is also applicable to a multicomponentGCL. 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 to
4、tal mass of the GCLfrom the total massof 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 theresponsi
5、bility 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. See Section 8 forspecific precautionary statements.2. Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD4439
6、Terminology for GeosyntheticsD4643 Test Method for Determination of Water (Moisture)Content of Soil by Microwave Oven HeatingD4753 Guide for Evaluating, Selecting, and Specifying Bal-ances and Standard Masses for Use in Soil, Rock, andConstruction Materials TestingE145 Specification for Gravity-Conv
7、ection and Forced-Ventilation OvensE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 Definitions:3.1.1 geosynthetic, na planar product manufactured frompolymeric material used with soil, rock, earth, or other geo-technical engineering r
8、elated material as an integral part of aman-made project, structure, or system. D44393.1.2 geosynthetic clay liner, na manufactured hydraulicbarrier consisting of clay bonded to a layer or layers ofgeosynthetic material(s).3.1.3 moisture content, nthat part of the mass of ageosynthetic clay liner th
9、at is absorbed water, compared to themass of dry clay.3.1.4 multicomponent GCL, nGCL with an attached film,coating, or membrane decreasing the hydraulic conductivity orprotecting the clay core, or both.3.1.5 oven-dried, adjthe condition of a material that hasbeen heated under prescribed conditions o
10、f 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 after drying in anoven over a sufficient time period to remove the moisture fromthe GCL.4.2
11、 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 area.NOTE 1The supplier of the geosynthetic clay liner must be able toverify that the actual ma
12、ss/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 for the synthetic component(s) (as obtained from themanufacturer for the actual lots used to
13、 make the GCL) rather than thenominal value.4.3 The moisture content of the GCL can be estimated withthis test method.5. Significance and Use5.1 This test method is used to determine if the GCLmaterial meets specifications for mass per unit area at approxi-mately 0 % moisture content, by oven-drying
14、. It can be used as1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.04 on Geosyn-thetic Clay Liners.Current edition approved Aug. 1, 2014. Published August 2014. Originallyapproved in 1996. Last previous edition ap
15、proved in 2009 as D5993 99(2009).DOI: 10.1520/D5993-14.2For 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.Copyri
16、ght ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1an index test for quality control or quality assurance todetermine specimen conformance.6. Atmosphere Conditions6.1 Atmospheric Conditions:6.1.1 The atmospheric conditions of the laboratory pe
17、rform-ing mass per unit area of GCLs shall be: relative humidity of 70 % and temperature of 23 6 4C.7. Apparatus7.1 Drying OvenThermostatically-controlled, preferablyof the forced-draft type, meeting the requirements of Specifi-cation E145 and capable of maintaining a uniform temperatureof 110 6 5C
18、throughout the drying chamber.7.2 Microwave OvenAmicrowave oven, preferably with avented chamber, is suitable. The required size and power ratingof the oven is dependent on its intended use. Ovens withvariable power controls and input power ratings of about700 W have been found to be adequate for th
19、is use. Variablepower controls are important and reduce the potential for overheating the test specimen.NOTE 2Microwave ovens equipped with built-in scales and computercontrols have been developed for use in drying soils. Their use iscompatible with this test method.7.3 BalancesAll balances must mee
20、t the requirements ofSpecification D4753 and this section. A Class GP1 balance of0.01 g readability is required for samples 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.7.4 Sample Containe
21、rsSuitable containers made of mate-rial resistant to corrosion and change in mass upon repeatedheating, cooling, exposure to materials of varying pH, andcleaning. Microwave sample containers should be microwavesafe.7.5 DesiccatorA desiccator cabinet or large desiccator jarof suitable size containing
22、 indicator silica gel. It is preferable touse a desiccant that changes color to indicate it needs recon-stitution.7.6 Container Handling ApparatusGloves, tongs, or suit-able holder for moving and handling hot containers afterdrying.7.7 Die, of known dimensions.7.8 Miscellaneous, knives, spatulas, sc
23、oops, quarteringcloth, sample splitters, and so forth, as required.8. Hazards/Precautions8.1 Handle hot containers with a container holder.8.2 Safety precautions supplied by the manufacturer of themicrowave oven should be observed.8.3 Do not use metallic containers in a microwave oven (ifused).9. Te
24、st Specimens9.1 The sample received at the testing laboratory should bein satisfactory condition and representative of the productmanufactured or delivered to a site, or both.9.2 A sample of a GCL should be cut into specimens in alaboratory using a die or sharp razor blade or razor knife.9.3 The min
25、imum size of the die or template for cuttingspecimens is 0.01 m2(for example, 10 by 10 cm).NOTE 3The use of small specimens are not recommended due to thepotential for edge loss of clay, which may create problems with accuracyand reproducibility.9.4 Test specimens taken from the laboratory sample sh
26、ouldbe free from imperfections or other areas not representative ofthe material samples (such as dirt or labels).9.5 Cutting 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 cleanedbefo
27、re cutting the specimen. Therefore, all excess or wastematerial should be cleaned away from the die and cutting areabefore 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 non-clingingclo
28、th or brush.9.6 The loss of clay during the specimen cutting processcould have a significant impact to the accuracy of this testmethod. The technician performing this test method shouldpractice cutting test specimens from the laboratory sample untilconfidence is gained that a specimen can be cut wit
29、houtsignificant loss of clay.9.6.1 The technician may choose to wet the perimeter of theGCL in an effort to bind the clay particles 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
30、 that will attach itself to the die, cuttingboard, template, or cutting instrument, or combination thereof.However, if the technician attempting to determine the mois-ture content of the GCL, other cutting methods should be usedthat do not require the addition of water.9.6.2 If a die is used to cut
31、the specimen, loss of clay can bereduced by leaving the die in place and removing all theremaining sample outside the edge of the die. This includesbrushing the cutting board clean. All material found within theedge of the die could then be placed in the sample containers.9.6.3 Any waste clay left o
32、n the cutting board and die orrazor for which the technician cannot determine if the claycame from the individual specimen or 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 o
33、f the waste clay shouldbe added to the test specimen container and the other one-halfdiscarded.9.7 The number of test specimens should be a minimum offive, cut such that they are representative of the entire rollwidth.10. Conditioning10.1 Bring the test specimens to moisture equilibrium in theatmosp
34、here for testing GCLs. Equilibrium is considered tohave been reached when the increase in mass of the testspecimen in successive weighing, made at intervals of not lessthan 2 h, does not exceed 0.1 % of the previous mass of the testD5993 142specimen. In general practice, the industry assumes equilib
35、-rium conditions exist in the “as-received” state.11. Procedure (Assuming Moisture Present)11.1 Using the die, or template 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 th
36、e sample, but should bedistributed across the sample.Any waste clay (including on thedie or razor) should be collected 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.11.2 The container to be
37、 used should be oven dried thor-oughly and subsequently placed into a desiccator until readyfor use so that the tare weight of the container will be recorded.11.3 Determine and record the tare of the specimen con-tainer.11.4 Select representative test specimens.11.5 Place the test specimen in the in
38、dividual container.Determine the mass of the container and GCL specimen asdelivered using a balance selected on the basis 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 contai
39、ner numbers shallbe recorded on the laboratory data sheets.11.6 Place the container with the GCL specimen in thedrying 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 typ
40、e of material, size of sample, oven typeand capacity, and other factors. The influence of these factorsgenerally can be 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 to16 h) is suffi
41、cient for conventional ovens. In cases where there is doubtconcerning the adequacy of drying, drying should be continued until thechange in mass after two successive periods (greater than 1 h) of drying isless than 0.1 %.NOTE 6If a microwave oven is used to dry the test specimen(s), theuser of this
42、test method should follow the drying procedures as stated inTest Method D4643. It is also recommended that the total mass 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
43、the same oven. However, this would not be applicable if the previouslydried specimens will remain in the drying oven for an additional timeperiod of about 16 h.11.7 After the material has dried to constant mass, removethe container from the oven (and replace the lid if used).Allowthe material and co
44、ntainer to cool to room temperature in adesiccation unit or until the container can be handled comfort-ably with bare hands 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 sa
45、me balance as used previously. Subtract the tare ofthe container from the mass of the sample to determine thesamples constant dry mass. Record this value (MGCL).12. Calculation12.1 Calculate the mass per unit area of each of thespecimens as follows:mGCL5 MGCL/A (1)where:mGCL= mass per unit area of t
46、he dried GCL productrounded to the nearest 0.1 g/m2,MGCL= the dried mass of GCL specimen measured to thenearest 0.01 g,= (oven-dried specimen + container mass) (taremass of container), andA = area of the specimen, m2(0.01 m2, if prepared inaccordance with 11.1).12.2 The mass per unit area of the cla
47、y component of theGCL can be estimated as follows:mclay5 mGCL2 ms(2)where:mclay= mass per unit area of dry clay component rounded tothe 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).12.3 The percent initial moistu
48、re content of the clay com-ponent of the GCL can be estimated as follows:wclay5Mi/A! 2 mGCLmclayx 100 (3)where:wclay= initial moisture content of the clay component of theGCL, percent, rounded to the nearest 0.1 %, andMi= initial mass of GCL specimen.12.4 Calculate the average of the mass per unit a
49、rea results(and moisture content results, if desired) for the test specimens.(WarningThe dried mass/unit area may include the presenceof adhesives, polymers, or other additives. Consult the GCLmanufacturer for additional information.)13. Report13.1 Report the following information on mass per unit areaof GCLs:13.1.1 Sample identification (for example, sample number,roll number, or other traceable identifier),13.1.2 Type of GCL tested, method used for cuttingspecimens, sample size, specimen size and shape, and numberof test specimens used,13.1.3 The assum
