1、Designation: D2168 10Standard Practices forCalibration of Laboratory Mechanical-Rammer SoilCompactors1This standard is issued under the fixed designation D2168; 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 These practices for the calibration of mechani
3、cal soilcompactors are for use in checking and adjusting mechanicaldevices used in laboratory compacting of soil and soil-aggregate in accordance with Test Methods D698, D1557,Practice D6026, and other methods of a similar nature thatmight specify these practices. Calibration for use with onepractic
4、e does not qualify the equipment for use with anotherpractice.1.2 The weight of the mechanical rammer is adjusted asdescribed in 5.4 and 6.5 in order to provide for the mechanicalcompactor to produce the same result as the manual compactor.1.3 Two alternative procedures are provided as follows:Secti
5、onPractice A Calibration based on the compaction of aselected soil sample5Practice B Calibration based on the deformation of astandard lead cylinder61.4 If a mechanical compactor is calibrated in accordancewith the requirements of either Practice A or Practice B, it isnot necessary for the mechanica
6、l compactor to meet therequirements of the other practice.1.5 The values stated in inch-pound units are to be regardedas the standard. The values given in parentheses are forinformation only.1.5.1 It is common practice in the engineering profession toconcurrently use pounds to represent both a unit
7、of mass (lbm)and a force (lbf). This implicitly combines two separatesystems of units; that is, the absolute system and the gravita-tional system. It is scientifically undesirable to combine the useof two separate sets of inch-pound units within a singlestandard. This standard has been written using
8、 the gravitationalsystem of units when dealing with the inch-pound system. Inthis system, the pound (lbf) represents a unit of force (weight).However, the use of balances or scales recording pounds ofmass (lbm) or the recording of density in lbm/ft3shall not beregarded as a nonconformance with this
9、standard.1.6 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.2. Ref
10、erenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil, Rock, and ContainedFluidsD698 Test Methods for Laboratory Compaction Character-istics of Soil Using Standard Effort (12 400 ft-lbf/ft3(600kN-m/m3)D1557 Test Methods for Laboratory Compaction Charac-teristics of Soil Using Modifi
11、ed Effort (56,000 ft-lbf/ft3(2,700 kN-m/m3)D2487 Practice for Classification of Soils for EngineeringPurposes (Unified Soil Classification System)D3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD60
12、26 Practice for Using Significant Digits in GeotechnicalDataE11 Specification for Woven Wire Test Sieve Cloth and TestSievesE145 Specification for Gravity-Convection and Forced-Ventilation Ovens3. Significance and Use3.1 Mechanical compactors are commonly used to replacethe hand compactors required
13、for Test Methods D698 andD1557 in cases where it is necessary to increase production.3.2 The design of mechanical compactors is such that it isnecessary to have a calibration process that goes beyonddetermining the mass and drop of the hammer.1These practices are under the jurisdiction ofASTM Commit
14、tee D18 on Soil andRock and are the direct responsibility of Subcommittee D18.03 on Texture,Plasticity and Density Characteristics of Soils.Current edition approved July 1, 2010. Published August 2010. Originallyapprroved in 1990. Last previous edition approved in 2002 as D216802a. DOI:10.1520/D2168
15、-10.2For 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.1*A Summary of Changes section appears at the end of this
16、 standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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.
17、 Agencies that meet thecriteria in Practice D3740 are generally considered capable of competentand objective testing/sampling/inspection/and the like. Users of thisstandard are cautioned that compliance with Practice D3740 does not initself assure reliable results. Reliable results depend on many fa
18、ctors;Practice D3740 provides a means of evaluating some of those factors.4. Apparatus4.1 For PracticeA, in addition to the apparatus requirementsspecified in Test Methods D698 and D1557, the following isrequired:4.1.1 Drying OvenThermostatically controlled oven,preferably of the forced-draft type,
19、meeting the requirementsfor Specification E145 and capable of maintaining a uniformtemperature of 140 6 5F (60 6 3C) throughout the dryingchamber.4.2 For Practice B, in addition to the apparatus requirementsspecified in Test Methods D698 and D1557, the following arerequired:4.2.1 Lead Deformation Ap
20、paratusA lead deformationapparatus consisting of an anvil, guide collar, and striking pin,as shown in Fig. 1.4.2.2 MicrometerA one-inch (25-mm) outside microme-ter or caliper reading to 0.001 in. (0.02 mm), for determiningthe length of the lead cylinders. As an alternative, a one-inch(25-mm) dial co
21、mparator reading to 0.001 in. (0.02 mm) maybe used to determine either the length of the lead cylinder, orof the complete lead deformation apparatus assembly. Tomeasure the complete assembly, a dial comparator with aminimum opening of 2 in. (50 mm) is required (see Fig. 2).NOTE 2The use of vernier c
22、alipers is not recommended since thevernier calipers can produce erroneous readings if not zeroed correctly, orif the vernier caliper is not of high quality.4.2.3 Guide Sleeve PedestalA guide sleeve pedestal foruse with guide sleeves used to control the drop of the manualrammers in Test Methods D698
23、 and D1557 (see Fig. 3).4.2.4 Test CylindersA supply of commercially pure leadtest cylinders having individual weights such that the lightestcylinder is within 0.06 g of the heaviest, each having a lengthof 0.675 6 0.005 in. (17.1 6 0.1 mm) and a diameter of 0.3106 0.002 in. (7.87 6 0.05 mm).3A mini
24、mum of ten testcylinders is required for the calibration of one mechanicalcompactor. However, depending on circumstances, as many as100 test cylinders may be required.5. ProcedurePractice A5.1 Evaluate the mechanical and manual compactors forevidence of wear, malfunction, and need of servicing andad
25、justment. Clean, adjust, and lubricate the compactors so as tomeet all requirements of the manufacturer, and the applicablemethod under which they will be used and for which themechanical compactor is to be calibrated. Operate the compac-tor for a minimum of 25 drops to cause friction in the parts t
26、obecome constant, allowing the rammer to fall on soil or othersoft material.NOTE 3In order to provide satisfactory results, mechanical compac-tors must be in excellent working condition. Improper operation of theraising and release mechanisms can introduce serious errors.5.2 Obtain approximately 50
27、lb (23 kg) of soil classified asCL in accordance with Classification D2487. If excessivemoisture is present, dry the soil until it becomes friable. Dryingmay be in air or by use of a drying apparatus such that thetemperature of the sample does not exceed 140F (60C). Passthe soil through a No. 4 (4.7
28、5-mm) sieve conforming to therequirements of Specification E11. Discard any material re-maining on the sieve, and thoroughly blend the materialpassing the sieve until it is uniform. The material shall then beprepared for compaction in accordance with either MethodsD698 or D1557 as appropriate for th
29、e mechanical compactorbeing calibrated.NOTE 4The amount of soil used will vary greatly depending on thenumber of water content unit mass determinations required.5.3 Using the soil prepared in accordance with 5.2, deter-mine optimum moisture and maximum dry unit weight byMethod A of either Test Metho
30、ds D698 or D1557 or whichevermethod is appropriate for the mechanical compactor beingcalibrated. Prepare one curve using the mechanical compactorand another using the manual compactor. Record the values ofgmax, the maximum dry unit weight obtained with the manualcompactor, and g8max, the maximum dry
31、 unit weight obtainedwith the mechanical compactor.5.4 Determine W, the percentage difference of maximumdry unit weight values for a single set of data (see Section 7).If the absolute value of W is equal to or less than 2.0, themechanical compactor is satisfactory for immediate use. If theabsolute v
32、alue of W is greater than 2.0, then obtain twoadditional sets of data. Use the same soil sample, prepared inaccordance with 5.2, that was used previously. Determine W,the average percentage difference of maximum dry unit massvalues for three sets of data (see Section 7). If the absolutevalue of W is
33、 equal to or less than 2.0, the mechanicalcompactor is satisfactory for immediate use. If the absolutevalue of Wis greater than 2.0, then adjust the rammer massof the mechanical compactor in accordance with 5.5. Thensecure three new values of g8maxand compute a new value ofW. Repeat this procedure u
34、ntil the absolute value of Wis equalto or less than 2.0.5.5 Make changes in the weight of the mechanical hammerwith due consideration to good workmanship. Makeshift modi-fications that could affect the operation of the mechanicalcompactor are not permitted. The maximum permissible varia-tion in the
35、weight of the mechanical hammer as the result ofcalibration is as follows: The total mass added to the originalmass of the hammer as received from the manufacturer mustnot exceed ten percent of its original mass. If it is necessary toadd more than ten percent, The mechanical compactor is to berebuil
36、t or repaired. If the calibration indicates that the mass ofthe original rammer needs to be reduced to less than 5.5 lbf3The sole source of supply of the lead test cylinders known to the committee atthis time is Hornady Manufacturing Co., P.O. Box 1848, Grand Island, Nebr. 68801in lots of 500. If yo
37、u are aware of alternative suppliers, please provide thisinformation to ASTM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.D2168 102(2.49 kg) or 10 lbf (4.54 kg) depending on the test methodrammer
38、standard, carefully recheck all equipment and calibra-tions and report the procedure. If removal of mass is stillindicated, the height-of-drop should be adjusted.NOTE 5Graphical procedures are helpful in estimating the correctamount of mass to be added or subtracted.5.6 If a larger change than that
39、permitted in 5.5 is found tobe necessary, then improper operation of the mechanicalin. mm2.10 53.34178 48158 41112 381.250 31.751.248 31.700.626 15.900.625 15.8812 130.317 8.0514 6.418 3.2116 1.6132 0.790.005 0.130.004 0.100.002 0.050.001 0.02NOTE 1Inside dimension of guide collar should slip easily
40、 over raised section of anvil without excessive free play. Anvil should slip easily insideguide sleeve pedestal without excessive free play.FIG. 1 Lead Deformation ApparatusD2168 103compactor is indicated. Evaluate and adjust the mechanicalcompactor in order to determine and eliminate the cause of t
41、hemalfunction and repeat the calibration procedure.5.7 Do not use the mechanical compactor if the indicatedweight change still exceeds that permitted in 5.5.6. ProcedurePractice B6.1 Evaluate and adjust the mechanical and manual com-pactors as described in 5.1 of Practice A.6.2 Deformation by the Ma
42、nual CompactorObtain thedeformation value for the manual compactor as follows:6.2.1 Select a set of lead cylinders from the same lot orshipment. Remove any burrs from the ends of the leadcylinders using a fine grade of emery cloth.NOTE 6Deformation of the lead cylinders is affected by changes intemp
43、erature. Take precautions to maintain the cylinders within 65F(62.7C) during the calibration of the mechanical compactor and thesecuring of the manual compactor values.6.2.2 Obtain c1, the (initial) micrometer or dial comparatorreading before impact, following the procedures decribed in6.2.5.6.2.3 P
44、lace the base plate of the compaction mold on a rigidfoundation. On the base plate, place the assembled leaddeformation apparatus with the lead cylinder (see Fig. 4) andguide sleeve pedestal in place. Insert the guide sleeve of themanual compactor into the recess in the guide sleeve pedestal.Check t
45、hat the distance from rammer release point to strikingpin contact meets the specified requirements. Apply one dropof the manual rammer with the guide sleeve of the manualcompactor held vertically, so that the rammer does not strikethe guide sleeve pedestal.6.2.4 Obtain c2, the micrometer or dial com
46、parator readingafter impact, following the procedures described in 6.2.5. Thedifference between dial readings c1and c2is equal to D, thedeformation value.6.2.5 Obtain readings for c1and c2either by:6.2.5.1 Direct measurement of the length of the lead cylin-der, using the outside micrometer caliper o
47、r an equivalent dialcomparator.in. mm8 20337625112514 6.418 3.20.001 0.02FIG. 2 Dial Comparatorin. mm2.77 70.42.13 54.1038 1018 3.20.03 0.80.005 0.13NOTE 1This dimension must be equal to the height of the leaddeformation apparatus when assembled with the lead cylinder in place,within a tolerance of
48、60.01 in. (60.25mm).NOTE 2DiameterAis such that guide sleeve of rammer fits easily intorecess without free play.FIG. 3 Guide Sleeve PedestalFIG. 4 Lead Deformation Apparatus AssemblyD2168 1046.2.5.2 Obtaining a measurement of the assembled defor-mation apparatus, secured by placing it in the dial co
49、mparatorso that the top center of the14-in. (6.4-mm) steel ball of thestriking pin is directly under the tip of the dial stem.6.2.6 Repeat 6.2.2-6.2.5 using an unused lead cylinder foreach determination until five deformation values are obtainedthat do not vary more than 2.0 % from D, the average value;that is, the absolute value of v1must be less than 2.0 for the fivevalues selected (see 7.2). The deformation value for the manualmethod shall be taken as D.6.3 Deformation by the Mechanical CompactorObtainthe deformation value (change i
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