1、Designation: D2980 171Standard Test Method forSaturated Density, Moisture-Holding Capacity, and Porosityof Saturated Peat Materials1This standard is issued under the fixed designation D2980; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, the year 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.1NOTEEditorially updated units of measurement statement in April 2018.1. Scope*1.1 This test method was design
3、ed to evaluate the aeration,water penetration, and water retention properties of peat underfield conditions of water saturation by measurement of thesaturated density, the moisture holding capacity, and theporosity.1.2 The values stated in SI units are to be regarded asstandard. The values given in
4、parentheses after SI units areprovided for information only and are not considered standard.1.3 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.3.1 The procedures used to specify how data are collected/recorded or c
5、alculated in this standard are regarded as theindustry standard. In addition, they are representative of thesignificant digits that generally should be retained. The proce-dures used do not consider material variation, purpose forobtaining the data, special purpose studies, or any consider-ations fo
6、r the users objectives; and it is common practice toincrease or reduce significant digits of reported data to becommensurate with these considerations. It is beyond the scopeof this standard to consider significant digits used in analysismethods for engineering design1.4 This standard does not purpo
7、rt 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, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard
8、 was developed in accor-dance with 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. Refer
9、enced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil, Rock, and ContainedFluidsD2974 Test Methods for Moisture, Ash, and Organic Matterof Peat and Other Organic SoilsD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in En
10、gineering Design and ConstructionD4753 Guide for Evaluating, Selecting, and Specifying Bal-ances and Standard Masses for Use in Soil, Rock, andConstruction Materials TestingD6026 Practice for Using Significant Digits in GeotechnicalDataE11 Specification for Woven Wire Test Sieve Cloth and TestSieves
11、3. Terminology3.1 Definitions:3.1.1 For common definitions of common terms in thisstandard, refer to Terminology D653.4. Summary of Test Method4.1 The test method sets up standardized conditions formeasuring the volume and mass of saturated peat. From thesedata, saturated volume, mass, moisture-hold
12、ing capacity (on amass and volume basis), dry peat volumes, and porosity can bedetermined.5. Significance and Use5.1 This test method measures the air-filled spaces (poros-ity) and the moisture-holding capacity of peat on both a massand a volume basis under conditions of saturation. If large1This te
13、st method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.22 on Media for PlantGrowth.Current edition approved Feb. 1, 2017. Published February 2017. Originallyapproved in 1971. Last previous edition approved in 2010 as D2980 04(201
14、0).DOI: 10.1520/D2980-17E01.2For 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.*A Summary of Changes section app
15、ears at the end of this standardCopyright 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 Decision on Princi
16、ples for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1spaces are present, water and air can penetrate easily. If spacesare smaller, the water holding capacity is increased. Waterholding capac
17、ity is larger in humified peat materials (smallinter-particulate spaces) (sapric soil), whereas water and air-penetration is larger in unhumified peat (larger inter-particulatespaces) (fibric soil). The spaces can also be an indication of theoxygen available to the plant roots.As such, the interplay
18、 of theproperties of moisture holding capacity and porosity dictate thebest use of the harvested organic soil material as well as thebest management practices for organic soils. The moistureretention relationships of these soils are critical to decisionsinvolving irrigation, drainage, and bearing ca
19、pacity of thesesoil.NOTE 1The quality of the result produced by this standard isdependent on the competence of the personnel performing it, and thesuitability of the equipment and facilities used. Agencies that meet thecriteria of Practice D3740 are generally considered capable of competentand objec
20、tive testing/sampling/inspection/etc. Users of this standard arecautioned that compliance with Practice D3740 does not in itself assurereliable results. Reliable results depend on many factors; Practice D3740provides a means of evaluating some of those factors.5.2 Water retention values are particul
21、arly important in themanagement of organic soils. There is much confusion in theliterature about the moisture retention values being expressedin various bases; as a percent by volume; as a percent of ovendry mass; or as the percent of the wet mass. In somemanagement decisions, it is necessary to exp
22、ress the watercontents of organic soils on a volume basis because of theirvaried bulk densities, but because of the volume reductionoccurring on drying, the water contents must also be expressedon a wet volume basis as collected in the field. Whereas, inother management decisions, moisture retention
23、 values are bestexpressed on a dry mass basis. For example, the difference inmass between the wet and oven dry sample is the moistureheld. These values are best expressed on a dry mass basis.Water holding capacities show a marked difference due to thedegree of decomposition in an organic soil. The m
24、ass of waterin fibric soil may be as much as 20 times the mass of the solidparticles, whereas that held in a sapric soil contains less thantwice the mass. If the water holding capacity is expressed on avolume basis these differences are much less apparent.6. Apparatus6.1 Dispensing Apparatus:6.1.1 T
25、wo dispensing burets, 250-cm3capacity in 1-cm3subdivisions, 62-cm3tolerance, pinch-cock type;6.1.2 A one-hole No. 6 rubber stopper;6.1.3 Straight polyethylene drying tube with serrated rubbertubing fittings, 150 mm long, 19 mm (34 in.) in outsidediameter, 16 mm (58 in.) in inside diameter;6.2 A 4-me
26、sh sieve conforming to Specification E11;6.3 Balance or Scale, a balance or scale for determining themass of the soil having a minimum capacity of 500 g andmeeting the requirements of Guide D4753 for a balance orscale of 0.01 g readability;6.4 A pre-tared moisture-proof (air-tight) container;6.5 A 5
27、-gal (20-L) bottle equipped with a siphon device;6.6 Stainless steel sieve circle about 16 mesh and 28.7 mmin diameter to be attached to one end of the drying tube andsealed. (A soldering iron is useful.) Adjust the length of thetube to match conveniently the graduation of the buret; then cutthe end
28、 without the sieve to allow for water drainage, and insertthe tube into the dispensing buret with the sieve side up.6.7 A square piece of rubber sheet, paper, or oil cloth to aidin mixing sample.7. Preparation of Sampling and Test SpecimensSampling, Test Specimens, and Test Units7.1 Sample:7.1.1 Obt
29、ain a sample as outlined in Section 7 of TestMethods D2974.7.1.2 Air-dry the sample in accordance with Method B,8.1.3.2 of Test Methods D2974 (air dried portion only).Determine and Record the moisture removed during air-dryingas a percentage of the as-received mass to the nearest 0.1 %.7.2 Test Spec
30、imen:7.2.1 Place a representative field sample about 300 g on asquare rubber sheet, paper, or oil cloth.7.2.2 Reduce the sample to the quantity required for aspecimen by quartering and place in a pre-tared moisture-proofcontainer. Work rapidly to prevent moisture losses.8. Procedure8.1 Determine the
31、 moisture content on a separate testspecimen by Method I or II of Test Methods D2974.8.1.1 Determine the mass of the buret fitted with the plastictube and screen. Working rapidly to prevent moisture losses,mix the sample thoroughly, place on top of a 4-mesh sieve, andshake until sieving is complete.
32、 Use only the portion that haspassed through the sieve for the determination. Firmly pack theburet with 250 mm (10 in.) of the material passing the 4-meshsieve as follows: Attach the rubber stopper to the delivery endof the buret.Add approximately 20-cm3portions of the sample,firmly tapping on the r
33、ubber stopper 3 times vertically from aheight of 150 mm (6 in.) for a final height of 250 mm (10 in.)(This will ensure that the height of the final wet volume is 190to 250 mm. (7.5 to 10 in.). Remove the stopper and weigh theburet to nearest 1 g.8.1.2 Position the buret to use a sink as the drain. P
34、lace a20-L (5-gal) bottle equipped with a siphon device above thelevel of the buret. Connect the clamped rubber tubing of thesiphon device to the buret by inserting glass tubing about 125mm (5 in.) and constricted at one end into the one-hole rubberstopper fitted tightly into the top of the buret.At
35、tach the rubbertubing with the pinch clamp to the delivery end of the buret.Open both clamps and pass water through the sample for morethan 24 h, maintaining a water reservoir over the sample at alltimes. (Moss-type samples may float but gradually settle as thesample becomes wet.) After initial soak
36、ing, regulate the waterflow through the column by adjusting the screw clamp at thedelivery end of the buret. (The in-flow of water should be aboutequal to the out-flow; a flow of about 1 drop/s is suitable.)When the sample is saturated, close both clamps and let thesample settle in water for about 5
37、 min. The top surface of thesample should be as level as possible.D2980 17128.1.3 Raise the buret and replace the rubber stopper on thedelivery end of the buret with a 250-cm3dispensing buret filledwith water, using the rubber stopper for the connection.Connect the two burets tightly, with no air le
38、aks. Remove thesiphon device and open the outlet clamps on both burets toempty. (The suction created is equivalent to about 38 mm (15in.) of water. Check for air leaks to ensure that the standardsuction is exerted on the sample. It is important to removeexcess water as described.) Measure the height
39、 of the wet peat.The height should be 190 to 250 mm (7.5 to 10 in.). Record thevolume in millilitres and determine the mass of the buret, theplastic tube with the sieve, and the wet peat to the nearest 1 g.Wet the sample again as above for more than 1 h, drain bysuction, record the volume, and mass.
40、 Repeat until consistentresults are obtained.9. Calculation9.1 Calculate the saturated density, S, in grams per cubiccentimetre as follows:As-received:S 5 Wr/Vw(1)Oven-dried:S 5 Wd/Vw(2)Wet:S 5 Ww/Vw(3)where:Wr= mass of test specimen as received, g,Vw= wet volume, cm3,Wd= mass of oven-dried test spe
41、cimen,g=Wr (100 M)/100,M = moisture, %, andWw= mass of wet (saturated) test specimen, g.9.2 Calculate the moisture-holding capacity in percent asfollows:9.2.1 Mass basis, W: As-received:W 5 Ww2 Wr! 3100#/Wr(4)Oven-dried:W 5 Ww2 Wd! 3100#/Wd(5)9.2.2 Volume basis, V:V 5 Ww2 Wd! 3100#/Vw31.0! (6)Where
42、1.0 = Density of Water (g/cm3)9.3 Calculate the dry peat volume (density), P, in percent asfollows:P 5 Wd3100!/Vw31.4! (7)Where 1.4 = Density of Peat (g/cm3)9.4 Calculate the porosity, A, in percent as follows:A 5 100 2 V1P! (8)10. Report: Test Data Sheet(s)/Form(s)10.1 The methodology used to speci
43、fy how data are re-corded on the test data sheet(s)/form(s), is given below, iscovered in 1.3.10.2 Record as a minimum the following general informa-tion (data):10.2.1 Sample/specimen identifying information, such asdescription and manufacturer of the peat.10.2.2 Any special selection and preparatio
44、n process.10.2.3 Technician name or initials, method used, and date.10.3 Record as a minimum the following test specimendata:10.3.1 Report the saturated density to the nearest 0.01g./cm3(D6026).10.3.2 Report the moisture holding capacity on both a drymass and volume basis to the nearest whole number
45、 percentage(D6026).10.3.3 Report the porosity to the nearest whole numberpercentage (D6026).11. Precision and Bias11.1 PrecisionTest data precision is not presented due tothe nature of materials tested. Due to the nature of the soil orrock materials tested by this method. It is either not feasible o
46、rtoo costly at this time to have ten or more laboratoriesparticipate in a round-robin testing program. Also, it is notfeasible or too costly to produce multiple specimens that haveuniform physical properties.Any variation observed in the datais just as likely to be due to specimen variation as to op
47、eratoror laboratory testing variation.11.1.1 Subcommittee D18.22 is seeking any data from theusers of this test method that might be used to make a limitedstatement on precision. It welcomes proposals that would allowfor development of a valid precision statement.11.2 BiasThere is no accepted refere
48、nce value for this testmethod, therefore, bias cannot be determined.12. Keywords12.1 moisture; moisture holding capacity; peat; porosityD2980 1713SUMMARY OF CHANGESIn accordance with Committee D18 policy, this section identifies the location of changes to this standard sincethe last edition (D298004
49、(2010) that may impact the use of this standard. (February 1, 2017)(1) Removed Footnotes 3 and 4.(2) Corrected typos.(3) Added Units section to Scope.(4) Changed reference to “weigh” to “determine the mass of.”(5) Changed reference to “scallop” to “cut.”(6) Added “Density” to “volume mass” and “dry peat volume”for clarification.(7) Changed mL to cm3.(8) Updated Precision section.(9) Added reference to D6026.(10) Updated Report section.(11) Updated significance and use discussion.(12) Updated Sample Preparation section.ASTM International takes no position
