1、Designation: D 5993 99 (Reapproved 2004)Standard Test Method forMeasuring Mass Per Unit of Geosynthetic Clay Liners1This standard is issued under the fixed designation D 5993; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea
2、r of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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
3、 liner(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 GCL from the total mas
4、sof the dry GCL.1.2 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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use
5、. See Section 7 forspecific precautionary statements.2. Referenced Documents2.1 ASTM Standards:2D 123 Terminology Relating to TextilesD 2216 Test Method for Laboratory Determination of Water(Moisture) Content of Soil and Rock by MassD 4354 Practice for Sampling of Geosynthetics for TestingD 4439 Ter
6、minology for GeosyntheticsD 4643 Test Method for Determination of Water (Moisture)Content of Soil by the Microwave Oven MethodD 4753 Guide for Evaluating, Selecting, and SpecifyingBalances and Standard Masses for Use in Soil, Rock, andConstruction Materials TestingD 5261 Test Method for Measuring Ma
7、ss per Unit Area ofGeotextilesE 145 Specification for Gravity-Convection and ForcedVentilation OvensE 691 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
8、 used with soil, rock, earth, or other geo-technical engineering related material as an integral part of aman-made project, structure, or system. D 44393.1.2 geosynthetic clay liner, na manufactured hydraulicbarrier consisting of clay bonded to a layer or layers ofgeosynthetic material(s). (Currentl
9、y 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 oven-dried, adjthe condition of a material that hasbeen heated under prescribed conditions of temperature andhu
10、midity until there is no further significant change in its mass.D 1234. 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 The mass per unit
11、 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 mass/unit area of th
12、e 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 make the GCL) rat
13、her 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 0 %moisture content, by oven-drying. It can be used as an index1This
14、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, 2004. Published July 2004. Originally approvedin 1996. Last previous edition approved in 1999 as D 5993 99
15、.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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box
16、 C700, West Conshohocken, PA 19428-2959, United States.test for quality control or quality assurance to determinespecimen conformance.6. Apparatus6.1 Drying OvenThermostatically-controlled, preferablyof the forced-draft type, meeting the requirements of Specifi-cation E 145 and capable of maintainin
17、g a uniform temperatureof 110C 6 5C throughout the drying chamber.6.2 Microwave OvenA microwave oven, preferably witha vented chamber, is suitable. The required size and powerrating of the oven is dependent on its intended use. Ovens withvariable power controls and input power ratings of about 700W
18、have been found to be adequate for this use. Variable powercontrols are important and reduce the potential for over heatingthe 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 met
19、hod.6.3 BalancesAll balances must meet the requirements ofSpecification D 4753 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 havin
20、g amass over 200 g.6.4 Sample ContainersSuitable 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.6.5 DesiccatorA desiccator cabinet or large des
21、iccator jarof suitable size containing indicator silica gel. It is preferable touse a desiccant that changes color to indicate it needs recon-stitution.6.6 Container Handling ApparatusGloves, tongs, or suit-able holder for moving and handling hot containers afterdrying.6.7 Die, of known dimensions.6
22、.8 Miscellaneous, knives, spatulas, scoops, quarteringcloth, sample splitters, and so forth, as required.7. Hazards/Precautions7.1 Handle hot containers with a container holder.7.2 Safety precautions supplied by the manufacturer of themicrowave oven should be observed.7.3 Do not use metallic contain
23、ers in a microwave oven (ifused).8. Test Specimens8.1 The sample received at the testing laboratory should bein satisfactory condition and representative of the 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
24、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 are not recommended due to thepotential for edge loss of clay, which may create problems with accuracyand reproducibility.8.4 Test specime
25、ns taken from the laboratory sample shouldbe free from imperfections or other areas not representative ofthe material samples (such as dirt or labels).8.5 Cutting of the laboratory specimens with a die or razormay contaminate the work area, die, or razor with particles ofclay or geosynthetic materia
26、l. The work area should be cleanedbefore 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 shou
27、ld 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 testmethod. The technician performing this test method shouldpractice cutting test specimens from the laboratory sample untilconfidence is
28、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 particles together and therebyreduce the possibility of clay granule loss during the cuttingprocess. If the sample is wetted, the technician
29、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 technician attempting to determine the mois-ture content of the GCL, other cutting methods should be usedthat do not require the addition of
30、 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 of the die. This includesbrushing the cutting board clean. All material found within theedge of the die could then be placed in the sample c
31、ontainers.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 or the original sampleshould be collected and weighed. It should be assumed thewaste clay is edge loss from the individual specimen and theo
32、riginal 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 specimens should be a minimum offive, cut such that they are representative of the entire rollwidth.9. Conditioning9.1 Bring the test specimens t
33、o moisture equilibrium in theatmosphere 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, th
34、e industry assumes equilib-rium conditions exist in the “as-received” state.10. Procedure (Assuming Moisture Present)10.1 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 sel
35、ected from locations on the sample, but should bedistributed across the sample. Any waste clay (including on theD 5993 99 (2004)2die 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 othe
36、r 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 weight of the container will be recorded.10.3 Determine and record the tare of the specimen con-tainer.10.4 Select representative test spec
37、imens.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 basis of the samplemass. Record the value of the GCL specimen (Mi).NOTE 4To prevent mixing of samples and yielding of incorrectresults, all
38、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 oven. Dry the GCL specimen to a constant mass.Maintain the drying oven at 110 6 5C unless otherwisespecified. The time required to obtain
39、 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 established by good judgment, experiencewith the materials being tested, and the apparatus being used.NOTE 5In most cases, drying a test
40、 sample overnight (about 12 to 16h) is sufficient 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 dryingis less than 0.1 %.NOTE 6If a microwave oven is used t
41、o dry the test specimen(s), theuser of this test method should follow the drying procedures as stated inTest Method D 4643. 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 shou
42、ld 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 for an additional timeperiod of about 16 h.10.7 After the material has dried to constant mass, removethe container from the oven (and repl
43、ace 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 hands and the operation of the balance will notbe affected by convection currents or its being heated, or both.Determine the mass of the
44、 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 constant dry mass. Record this value (MGCL).11. Calculation11.1 Calculate the mass per unit area of each of thespecimens as follows:mGCL5
45、 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,= (oven-dried specimen + container mass) (taremass of container), andA = area of the specimen, m2(0.01 m2, if prepared inaccordance wit
46、h 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 component roundedto the nearest 0.1 g/m2, andms= nominal mass per unit area of GCL syntheticcomponent(s), g/m2, as provided by manufacturer(se
47、e 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= initial moisture content of the clay component ofthe GCL, percent, rounded to the nearest 0.1 %,andMi= initial mass of GCL specimen.11.4
48、 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 include the presenceof adhesives or other additives. Consult the GCL manufacturer foradditional information.12. Report12.1 Report the
49、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 specification sheet),12.1.4 Drying time, temperature, and method used to dry,12.1.5 The average mass per unit area of the GCL (mGCL)tothe near
