ASTM_D_6758_-_18.pdf

Designation:D675818Standard Test Method forMeasuring Stiffness and Apparent Modulus of Soil and Soil-Aggregate In-Place by Electro-Mechanical Method1This standard is issued under the fixed designation D6758;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()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the measurement by electro-mechanical means of the in-place stiffness of soil or soil-aggregate mixtures so as to determine a Youngs modulusbased on certain assumptions.The apparatus and procedureprovide a fairly rapid means of testing so as to minimizeinterference and delay of construction.The test procedure isintended for evaluating the stiffness or modulus of materialsused in earthworks and roadworks.Rapid in-place stiffnesstesting supports U.S.federal and state efforts to specify thein-place performance of construction materials based on modu-lus.Results obtained from this method are applicable to theevaluation of granular cohesionless materials.They are alsoapplicable to the evaluation of silty and clayey materials withmore than 20%fines that are not subject to a change inmoisture content.If the silty and clayey material experiences achange in moisture content,then moisture content shall betaken into account if the results of this method are to beapplicable.The stiffness measured with this method is influ-enced by boundary conditions,specifically the support offeredby underlying layers as well as the thickness and modulus ofthe layer being tested.Since this method approximates thelayer(s)being evaluated as a half-space,then the modulusmeasured is also approximate.1.2 The stiffness,in force per unit displacement,is deter-mined by imparting a small measured force to the surface ofthe ground,measuring the resulting surface velocity andcalculating the stiffness.This is done over a frequency rangeand the results are averaged.1.3 The values stated in SI units are to be regarded as thestandard.The inch-pound units equivalents may be approxi-mate.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.NOTE1Notwithstanding the statements on precision and bias con-tained in this test method;the precision of this test method is dependenton the competence of the personnel performing it,and the suitability of theequipment and facilities used.Agencies that meet the criteria of PracticeD3740 are generally considered capable of competent and objectivetesting.Users of this test method are cautioned that compliance withPractice D3740 does not in itself assure reliable testing.Reliable testingdepends on many factors;Practice D3740 provides a means of evaluatingsome of those factors.1.5 This international standard 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.Referenced 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 Character-istics of Soil Using Modified Effort(56,000 ft-lbf/ft3(2,700 kN-m/m3)D2216 Test Methods for Laboratory Determination of Water(Moisture)Content of Soil and Rock by MassD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4220 Practices for Preserving and Transporting SoilSamplesD4643 Test Method for Determination of Water Content ofSoil and Rock by Microwave Oven Heating1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.08 on Special andConstruction Control Tests.Current edition approved Feb.15,2018.Published February 2018.Originallyapproved in 2002.Last previous edition approved in 2008 as D6758 08,whichwas withdrawn January 2017 and reinstated in February 2018.DOI:10.1520/D6758-18.2For 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.Copyright 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 stan