1、Designation: D5993 18Standard Test Method forMeasuring Mass per Unit Area 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 revis
2、ion. 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
3、 test 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 initi
4、al total 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 theres
5、ponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.See Section 8 for specific precautionary statements.1.4 This international standard was developed in accor-dance with
6、 internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:
7、2D123 Terminology Relating to TextilesD4439 Terminology for GeosyntheticsD4643 Test Method for Determination of Water Content ofSoil and Rock by Microwave Oven HeatingD4753 Guide for Evaluating, Selecting, and Specifying Bal-ances and Standard Masses for Use in Soil, Rock, andConstruction Materials
8、TestingE145 Specification for Gravity-Convection 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, e
9、arth, or other geo-technical engineering-related material as an integral part of amanmade 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 o
10、f the mass of ageosynthetic clay liner that 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 has
11、been 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 after drying in anoven over a sufficient time peri
12、od 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) and, if added, any additional components (for example,sand, bituminous layer, etc.) fro
13、m the total GCL mass per unitarea.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 b
14、y using theactual average value for the synthetic component(s) (as obtained from the1This 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 June 1, 2018. Published
15、June 2018. Originallyapproved in 1996. Last previous edition approved in 2014 as D5993 14. DOI:10.1520/D5993-18.2For 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
16、standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the
17、 Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1manufacturer for the actual lots used to make the GCL) rather than thenominal value.NOTE 2The supplier of the geosynth
18、etic clay liner must be able toverify that the actual mass/area of the additional components is with610 % of the reported nominal 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
19、specifications for mass per unit area at approxi-mately 0 % moisture content, by oven drying. It can be used asan 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
20、 perform-ing mass per unit area of GCLs shall be: relative humidity of70 % and temperature of 23 6 4 C.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
21、5 C 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 fo
22、r this use. Variablepower controls are important and reduce the potential foroverheating the test specimen.NOTE 3Microwave 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
23、meet the requirements ofGuide D4753 and this section. A Class GP1 balance of 0.01-greadability is required for samples having a mass of up to 200 g(excluding mass of sample container) and a Class GP2 balanceof 0.1-g readability is required for samples having a mass over200 g.7.4 Sample ContainersSui
24、table 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 indi
25、cator 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 MiscellaneousKnives, spatulas, scoops, q
26、uarteringcloth, 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. Test Spec
27、imens9.1 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 minimum si
28、ze of the die or template for cuttingspecimens is 0.01 m2(for example, 10 by 10 cm).NOTE 4The 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 shouldbe
29、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 cleanedbefore cutt
30、ing 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-clingingcloth or b
31、rush.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 withoutsig
32、nificant loss of clay.9.6.1 The technician may choose to wet the perimeter of theGCLin 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 that w
33、ill attach itself to the die, cuttingboard, template, or cutting instrument, or combination thereof.However, if the technician is attempting to determine themoisture content of the GCL, other cutting methods should beused that do not require the addition of water.9.6.2 If a die is used to cut the sp
34、ecimen, 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 on the
35、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 theD5993 182original sample. One half the weigh
36、t of the waste clay shouldbe added to the test specimen container and the other 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 theatmosph
37、ere 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 testspecimen. In general practice, the industry assumes equilib-rium cond
38、itions 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 the sample,
39、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 halfdiscarded.11.2 The container to be used should b
40、e 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 individual conta
41、iner.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 5To prevent mixing of samples and yielding of incorrectresults, all containers should be numbered and the container numbers sh
42、allbe 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 5 C unless otherwisespecified. The time required to obtain constant mass will varydepending on the type of material
43、, 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 6In most cases, drying a test sample overnight (about 12 to16 h) is sufficient for con
44、ventional 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 7If a microwave oven is used to dry the test specimen(s), theuser of this test method s
45、hould 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 8Since some dry materials may absorb moisture from moistsamples, dried samples should be removed before placing moist samplesin the same oven
46、. 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 container to co
47、ol 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 same balance a
48、s 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 the dried GC
49、L 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 clay component of theGCL can be estimated as follows:mclay5 mGCL2 ms2 mac(2)where:mclay= mass per unit area of dry clay component rounded tothe nearest 0.1 g/m2,ms= nominal mass per unit area of GCL syntheticcomponent(s), g/m2, as provided by manufacturer(see 4.2, Note 1),
