ASTM_D_2950_-_D_2950M_-_14.pdf

Designation:D2950/D2950M14Standard Test Method forDensity of Bituminous Concrete in Place by NuclearMethods1This standard is issued under the fixed designation D2950/D2950M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method describes a test procedure for deter-mining the density of bituminous concrete by the attenuation ofgamma 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 or source remains on the surface(Direct TransmissionMethod).1.2 The density,in mass per unit volume of the materialunder test,is determined by comparing the detected rate ofgamma emissions with previously established calibration data.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.1.4 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 specificwarning statements see Section 6 and Note 5.2.Referenced Documents2.1 ASTM Standards:2C670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsD1188 Test Method for Bulk Specific Gravity and Density ofCompacted Bituminous Mixtures Using Coated SamplesD1559 Test Method for Resistance to Plastic Flow of Bitu-minous Mixtures Using Marshall Apparatus(Withdrawn1998)3D2041 Test Method for Theoretical Maximum SpecificGravity and Density of Bituminous Paving MixturesD2726 Test Method for Bulk Specific Gravity and Densityof Non-Absorptive Compacted Bituminous MixturesD3665 Practice for Random Sampling of Construction Ma-terialsD6752 Test Method for Bulk Specific Gravity and Densityof Compacted Bituminous Mixtures Using AutomaticVacuum Sealing MethodD7013 Guide for Nuclear Surface Moisture and DensityGauge Calibration Facility SetupD7759 Guide for Nuclear Surface Moisture and DensityGauge Calibration3.Significance and Use3.1 The test method described is useful as a rapid,nonde-structive technique for determining the in-place density ofcompacted bituminous mixtures.3.2 With proper calibration and confirmation testing,the testmethod is suitable for quality control and acceptance testing ofcompacted bituminous concrete.3.3 The test method can be used to establish the properrolling effort and pattern to achieve the required density.3.4 The non-destructive nature of the test allows repetitivemeasurements to be made at a single test location betweenroller passes and to monitor changes in density.3.5 The density results obtained by this test method arerelative.Correlation with other test methods such as D1188 orD2726 are required to convert the results obtained using thismethod to actual density.It is recommended that at least sevencore densities and seven nuclear densities be used to establisha conversion factor.A new factor must be established at anytime a change is made in the paving mixture or in theconstruction process.1This test method is under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.21 onSpecific Gravity and Density of Asphalt Mixtures.Current edition approved June 1,2014.Published August 2014.Originallyapproved in 1971.Last previous edition approved in 2011 as D2950/D2950M 11.DOI:10.1520/D2950_D2950M-14.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.Interferences4.1 The chemical composition of the material being testedmay significantly affect the measurement and adjustments maybe necessary.Certain elements with atomic numbers greaterthan 20 may cause erroneously high test values.4.2 The test method exhibits spatial bias in that the instru-ment is most sensitive to the density of the material in closestproximity to the nuclear source.4.2.1 When measuring the density of an overlay,it may benecessary to employ a correction factor if the underlyingmaterial varies in thickness,mineral composition or degree ofconsolidation at different points within