1、Designation: D5874 16Standard Test Methods forDetermination of the Impact Value (IV) of a Soil1This standard is issued under the fixed designation D5874; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 These test methods cover the determination of theImpact Value (IV) of a soil either in the field or a test mold, asfollows:1.1.1 Field
3、 Procedure ADetermination of IV alone, in thefield.1.1.2 Field Procedure BDetermination of IV and watercontent, in the field.1.1.3 Field Procedure CDetermination of IV, watercontent, and dry density, in the field.1.1.4 Mold ProcedureDetermination of IV of soil com-pacted in a mold, in the lab.1.2 Th
4、e standard test method, using a 4.5 kg (10 lbm)hammer, is suitable for, but not limited to, evaluating thestrength of an unsaturated compacted fill, in particular pave-ment materials, soils, and soil-aggregates having maximumparticle sizes less than 37.5 mm (1.5 in.).1.3 By using a lighter 0.5 kg (1
5、.1 lbm) or 2.25 kg (5 lbm)hammer, this test method is applicable for evaluating lowerstrength soils such as fine grained cohesionless, highly organic,saturated, or highly plastic soils having a maximum particlesize less than 9.5 mm (0.375 in.), or natural turfgrass.1.4 By using a heavier 10 kg (22 l
6、bm) or 20 kg (44 lbm)hammer, this test method is applicable for evaluating for hardermaterials at the top end the scales or beyond the ranges of thestandard and lighter impact soil testers.1.5 By performing laboratory test correlations for a particu-lar soil using the 4.5 kg (10 lbm) hammer, IV may
7、be correlatedwith an unsoaked California Bearing Ratio (CBR) or may beused to infer percentage compaction.1.6 The values stated SI are to be regarded as the standard.The values stated in parentheses are given for information only.1.7 All observed and calculated values shall conform to theguidelines
8、for significant digits and rounding established inPractice D6026.1.8 For purposes of comparing, a measured or calculatedvalue(s) with specified limits, the measured or calculatedvalue(s) shall be rounded to the nearest decimal or significantdigits in the specified limits.1.8.1 The procedures used to
9、 specify how data are collected/recorded or calculated, 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, spec
10、ial purpose studies, or any consider-ations for 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 engi
11、neering design.1.9 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.
12、NOTE 1The equipment and procedures contained in this test methodare similar to those developed by B. Clegg in the 1970s at the Universityof Western Australia, Nedlands, Australia. Impact Value is also commonlyknown as Clegg Impact Value (CIV).2. Referenced Documents2.1 ASTM Standards:2D653 Terminolo
13、gy 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)D1556 Test Method for Density and Unit Weight of Soil inPlace by Sand-Cone MethodD1557 Test Methods for Laboratory Compaction Charact
14、er-istics of Soil Using Modified Effort (56,000 ft-lbf/ft3(2,700 kN-m/m3)D1883 Test Method for California Bearing Ratio (CBR) ofLaboratory-Compacted Soils1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.08 on Specia
15、l andConstruction Control Tests.Current edition approved Jan. 1, 2016. Published January 2016. Originallyapproved in 1995. Last previous edition approved in 2007 as D5874 02(2007).DOI: 10.1520/D5874-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Serv
16、ice 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 appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-
17、2959. United States1D2167 Test Method for Density and Unit Weight of Soil inPlace by the Rubber Balloon MethodD2216 Test Methods for Laboratory Determination of Water(Moisture) Content of Soil and Rock by MassD2937 Test Method for Density of Soil in Place by theDrive-Cylinder MethodD3740 Practice fo
18、r Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4643 Test Method for Determination of Water (Moisture)Content of Soil by Microwave Oven HeatingD4959 Test Method for Determination of Water (Moisture)Content of Soil
19、 By Direct HeatingD6026 Practice for Using Significant Digits in GeotechnicalDataD6938 Test Methods for In-Place Density and Water Contentof Soil and Soil-Aggregate by Nuclear Methods (ShallowDepth)3. Terminology3.1 Definitions:3.1.1 Except as listed in 3.2, all definitions are in accordancewith Ter
20、minology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 as-compacted target IV, nthe desired strength, interms of IV, to be achieved in the field for a particular materialand construction process, at the as-compacted moisture condi-tion. This may also be referred to as the as-compacte
21、d targetstrength.3.2.2 dried-back target IV, nthe desired strength, in termsof IV, to be achieved in the field for a particular material andconstruction process prior to continuing with a subsequentlayer, or sealing, or opening to traffic, after moisture has left thesystem through evaporation and/or
22、 drainage. This may also bereferred to as the dried-back target strength.3.2.3 heavy impact value (IV/H), nthe IV derived fromusing a 20 kg (44 lbm) mass hammer 130 mm (5 in.) indiameter free falling 300 mm (12 in.).3.2.4 heavy medium heavy impact value (IV/HMH), ntheIV derived from using a 10 kg (2
23、2 lbm) mass hammer 130 mm(5 in.) in diameter free falling 300 mm (12 in).3.2.5 impact soil tester, ntesting apparatus used to obtainan IV of a soil.3.2.6 impact value (IV), nthe value expressed in units oftens of gravities (g) and reported to the nearest whole numberderived from the peak deceleratio
24、n of a 4.5 kg (10 lbm)instrumented compaction hammer 50 mm (2.0 in.) in diameterfree falling 450 mm (18 in.).3.2.7 in-service target IV, nthe desired strength, in termsof IV, to be achieved in the field for a particular material andconstruction process once the road is opened to traffic and hasreach
25、ed equilibrium. This may also be referred to as thein-service target strength.3.2.8 light impact value (IV/L), nthe IV derived fromusing a 0.5 kg (1.1 lbm) mass hammer 50 mm (2.0 in.) indiameter free falling 300 mm (12 in.).3.2.9 medium impact value (IV/M), nthe IV derived fromusing a 2.25 kg (5 lbm
26、) mass hammer 50 mm (2.0 in) indiameter free falling 450 mm (18 in.).4. Summary of Test Method4.1 The test apparatus is placed on the material to be testedeither in a mold or on naturally occurring or compacted soil inthe field. The hammer is raised to a set height and allowed tofree fall. The instr
27、umentation of the test apparatus displays avalue in tens of gravities (g) of the peak deceleration of thehammers impact as recorded by an accelerometer fitted to thetop of the hammer body. A total of four blows of the hammerare applied on the same spot to determine the IV for each testperformed.4.2
28、A lighter hammer of 0.5 kg (1.1 lbm) or 2.25 kg (5 lbm)may be used for softer conditions or fragile materials instead ofthe 4.5 kg (10 lbm) standard hammer to determine the IV.When used the resulting value is termed the Light Impact Value(IV/L) for the 0.5 kg (1.1 lbm) hammer or Medium ImpactValue (
29、IV/M) for the 2.25 kg (5 lbm) hammer.4.3 Alarger, heavier hammer of 10 kg (22 lbm) or 20 kg (44lbm) may be used instead of the 4.5 kg (10 lbm) standardhammer to determine the IV for harder conditions or to testthrough a larger zone both horizontally and vertically. Whenused, the resulting value is t
30、ermed the Heavy Medium HeavyImpact Value (IV/HMH) for the 10 kg (22 lbm) hammer orHeavy Impact Value (IV/H) for the 20 kg (44 lbm) hammer.5. Significance and Use5.1 Impact Value, as determined using the standard 4.5 kg(10 lbm) hammer, has direct application to design and con-struction of pavements a
31、nd a general application to earthworkscompaction control and evaluation of strength characteristicsof a wide range of materials, such as soils, soil aggregates,stabilized soil and recreational turf. Impact Value is one of theproperties used to evaluate the strength of a layer of soil up toabout 150
32、mm (6 in.) in thickness and by inference to indicatethe compaction condition of this layer. Impact Value reflectsand responds to changes in physical characteristics that influ-ence strength. It is a dynamic force penetration property andmay be used to set a strength parameter.5.2 This test method pr
33、ovides immediate results in terms ofIV and may be used for the process control of pavement orearthfill activities where the avoidance of delays is importantand where there is a need to determine variability whenstatistically based quality assurance procedures are being used.5.3 This test method does
34、 not provide results directly as apercentage of compaction but rather as a strength index valuefrom which compaction may be inferred for the particularmoisture conditions. From observations, strength either re-mains constant along the dry side of the compaction curve orelse reaches a peak and declin
35、es rapidly with increase in watercontent slightly dry of optimum water content. This is gener-ally between 95 and 98 % maximum dry density (see Fig. 1 andFig. 2). An as-compacted target strength in terms of IV may bedesignated from laboratory testing or field trials as a strength toachieve in the fi
36、eld as the result of a compaction process for aD5874 162desired density and water content. If testing is performed aftercompaction when conditions are such that the water contenthas changed from the critical value, determination of the actualwater content by laboratory testing enables the field dens
37、ity tobe inferred from regression equations using IV, density andwater content.NOTE 2Impact Value may be used as a means to improve thecompaction process by giving instant feedback on roller efficiency,uniformity, confirming the achievement of the target strength, and byinference the achieved densit
38、y. When inferring density from IV, however,it should be considered as only indicative of density. Where strictacceptance on a density ratio basis is required, test methods that measuredensity directly shall be used.5.4 This test method may be used to monitor strengthchanges during a compaction proce
39、ss or over time due toseasonal, environmental or traffic changes.NOTE 3For in-place soil strength evaluation where there may be a dryand hard surface layer (crust), testing both the crust and the underlyinglayer may be required.5.5 The standard instrument is based on a 4.5 kg (10 lbm)compaction hamm
40、er using a 450 mm (18 in.) drop height. Thehammer has been equipped with an accelerometer and instru-mented using a peak hold electronic circuit to read the peakdeceleration on impact. The circuitry is filtered electronicallyto remove unwanted frequencies and the peak deceleration isdisplayed in uni
41、ts of ten gravities (g) with the output belowunits of ten gravities truncated.5.6 The peak deceleration on which IV is derived representsthe area under the deceleration versus time curve which formost soils may be assumed as half a sinusoid. Applying doubleintegration provides first the time velocit
42、y relationship andsecond, the time penetration relationship. As force is alsodirectly related to deceleration, the IV therefore, representsboth stress and penetration and may be taken as a directmeasurement of stiffness or strength (see Fig. 3).5.7 Impact Value may be correlated with an unsoaked CBR
43、.5.8 Impact Value may be expressed as a hammer modulus,analogous with elastic modulus or deformation modulus.5.9 The light hammer uses the same accelerometer andinstrumentation as the standard hammer. The smaller mass of0.5 kg (1.1 lbm) results in more sensitivity for lower strengthmaterials compare
44、d to the standard mass; that is, the zero to100 IV scale is expanded with this lighter hammer mass andprovides more definition on softer materials. To avoidconfusion, the IV of the light hammer is notated as IV/L.5.10 Light Impact Value has applications for recreation turfhardness evaluation, where
45、the condition of the surface affectsball bounce characteristics, the performance or injury potentialto participants, and where more sensitivity compared to thestandard hammer is required or an imprint left by the 4.5 kg (10lbm) hammer or other test methods is undesirable, such as ona golf putting gr
46、een.FIG. 1 Illustration of Target IV for Material with No PeakFIG. 2 Illustration of Target IV for Material with Pronounced PeakD5874 1635.11 The medium hammer uses the same accelerometer andinstrumentation as the standard hammer and provides a sensi-tivity between that of the standard hammer and li
47、ght hammer.The IV of the medium hammer is notated as IV/M.5.12 The Medium Impact Value has application to sand andearthworks, and natural turfgrass and artificial turf hardnessevaluation, the last primarily in relation to performance orinjury potential to the participants, and is preferable over the
48、Light Impact Value in relation to thicker thatch and longergrass for such application.5.13 The heavy medium heavy hammer uses the sameaccelerometer and instrumentation as the standard hammer,and tests through a larger zone both horizontally and verticallybecause of its larger diameter mass. The IV o
49、f the heavymedium hammer is notated as IV/HMH.5.14 The Heavy Medium Heavy Impact Value has applica-tion to testing the same materials as those tested by thestandard, light and medium impact soil testers, for evaluationof a layer of soil up to about 380 mm.5.15 The heavy hammer uses the same accelerometer andinstrumentation as the standard hammer, and tests through alarger zone both horizontally and vertically. The IV of theheavy hammer is notated as IV/H.5.16 The Heavy Impact Value has application to testing thesame materials as those tested by the standard, li
