ASTM_D_2922_-_01.pdf

Designation:D 2922 01Standard Test Methods forDensity of Soil and Soil-Aggregate in Place by NuclearMethods(Shallow Depth)1This standard is issued under the fixed designation D 2922;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year 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.This standard has been approved for use by agencies of the Department of Defense.1.Scope1.1 These test methods cover the determination of the totalor wet density of soil and soil-rock mixtures by the attenuationof gamma radiation where the source and detector(s)remain onthe surface(Backscatter Method)or the source or detector isplaced at a known depth up to 300 mm(12 in.)while thedetector(s)or source remains on the surface(Direct Transmis-sion Method).1.2 The density in mass per unit volume of the materialunder test is determined by comparing the detected rate ofgamma radiation with previously established calibration data.1.3 The values tested in SI units are to be regarded as thestandard.The inch-pound equivalents may be approximate.1.4 It is common practice in the engineering profession toconcurrently use pounds to represent both a unit of mass(lbm)and a unit of 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.These test methods have been written using thegravitational system of units when dealing with the inch-poundsystem.In this system the pound(lbf)represents a unit of force(weight).However,the use of balances or scales recordingpounds of mass(lbm),or the recording of density in lbm/ft3should not be regarded as nonconformance with these testmethods.1.5 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.For specific Hazardstatements,see Section 6.2.Referenced Documents2.1 ASTM Standards:D 698Test Methods for Laboratory Compaction Charac-teristics of Soil Using Standard Effort(12,400 ft-lbf/ft3(600 kN-m/m3)2D 1557 Test Methods for Laboratory Compaction Charac-teristics of Soil Using Modified Effort(56,000 ft-lbf/ft3(2,700 kN-m/m3)2D 2216 Test Method for Laboratory Determination of Water(Moisture)Content of Soil and Rock by Mass2D 3017 Test Method for Water Content of Soil and RockIn-Place by Nuclear Methods(Shallow Depth)2D 4253 Test Method for Maximum Index Density and UnitWeight of Soils Using a Vibratory Table2D 4643 Test Method for Determination of Water Content bythe Microwave Oven Heating2D 4718 Practice for Correction of Unit Weight and WaterContent for Soils Containing Oversize Particles2D 4944 Test Method for Field Determination of Water(Moisture)Content of Soil by the Calcium Carbide GasPressure Tester Method2D 4959 Test Method for Determination of Water(Moisture)Content by Direct Heating23.Significance and Use3.1 The test methods described are useful as rapid,nonde-structive techniques for the in-place determination of density ofsoil and rock.3.2 The test methods are suitable for quality control andacceptance testing for construction and for research anddevelopment applications.3.3 The nondestructive nature of the tests allow repetitivemeasurements to be made at a single test location.4.Interferences4.1 The chemical composition of the sample may affect themeasurement,and adjustments may be necessary.4.2 The test methods exhibit spatial bias in that the instru-ment is more sensitive to the density of the material in closeproximity to the surface(Backscatter Method only).NOTE1The nuclear gauge density measurements are somewhatbiased to the surface layers of the soil being tested.This bias has largely1These test methods are under the jurisdiction ofASTM Committee D18 on Soiland Rock and are the direct responsibility of Subcommittee D18.08 on Special andConstruction Control Tests.Current edition approved June 10,2001.Published August 2001.Originallypublished as D 2922 71.Last previous edition D 2922 96e1.2Annual Book of ASTM Standards,Vol 04.08.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.been corrected out of the direct transmission method and any remainingbias is insignificant.The backscatter method is still more sensitive to thematerial within the first several inches from the surface.4.3 Oversize rocks or large voids in the source-detector pathmay cause higher or lower density determination.Where lackof uniformity in the soil due to layering,rock or voids issuspected,the test volume site should be dug up and visuallyexamined to determine if the test mate