ASTM_C_215_-_14.pdf

Designation:C21514Standard Test Method forFundamental Transverse,Longitudinal,andTorsional Resonant Frequencies of Concrete Specimens1This standard is issued under the fixed designation C215;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope*1.1 This test method covers measurement of the fundamen-tal transverse,longitudinal,and torsional resonant frequenciesof concrete prisms and cylinders for the purpose of calculatingdynamic Youngs modulus of elasticity,the dynamic modulusof rigidity(sometimes designated as“the modulus of elasticityin shear”),and dynamic Poissons ratio.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 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.Referenced Documents2.1 ASTM Standards:2C31/C31M Practice for Making and Curing Concrete TestSpecimens in the FieldC42/C42M Test Method for Obtaining and Testing DrilledCores and Sawed Beams of ConcreteC125 Terminology Relating to Concrete and Concrete Ag-gregatesC192/C192M Practice for Making and Curing Concrete TestSpecimens in the LaboratoryC469/C469M Test Method for Static Modulus of Elasticityand Poissons Ratio of Concrete in CompressionC670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsE1316 Terminology for Nondestructive Examinations3.Terminology3.1 DefinitionsRefer to Terminology C125 and the sectionrelated to ultrasonic examination in Terminology E1316 fordefinitions of terms used in this test method.4.Summary of Test Method4.1 The fundamental resonant frequencies are determinedusing one of two alternative procedures:(1)the forced reso-nance method or(2)the impact resonance method.Regardlessof which testing procedure is selected,the same procedure is tobe used for all specimens of an associated series.4.2 In the forced resonance method,a supported specimen isforced to vibrate by an electro-mechanical driving unit.Thespecimen response is monitored by a lightweight pickup uniton the specimen.The driving frequency is varied until themeasured specimen response reaches a maximum amplitude.The value of the frequency causing maximum response is theresonant frequency of the specimen.The fundamental frequen-cies for the three different modes of vibration are obtained byproper location of the driver and the pickup unit.4.3 In the impact resonance method,a supported specimenis struck with a small impactor and the specimen response ismeasured by a lightweight accelerometer on the specimen.Theoutput of the accelerometer is recorded.The fundamentalfrequency of vibration is determined by using digital signalprocessing methods or counting zero crossings in the recordedwaveform.The fundamental frequencies for the three differentmodes of vibration are obtained by proper location of theimpact point and the accelerometer.5.Significance and Use5.1 This test method is intended primarily for detectingchanges in the dynamic modulus of elasticity of laboratory orfield test specimens that are undergoing exposure to weatheringor other types of potentially deteriorating influences.The testmethod may also be used to monitor the development ofdynamic elastic modulus with increasing maturity of testspecimens.5.2 The value of the dynamic modulus of elasticity obtainedby this test method will,in general,be greater than the static1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregatesand is the direct responsibility of SubcommitteeC09.64 on Nondestructive and In-Place Testing.Current edition approved Dec.15,2014.Published January 2015.Originallyapproved in 1947.Last previous edition approved in 2008 as C215 08.DOI:10.1520/C0215-14.2For 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 modulus of elasticity obtained by using Test Method C469/C469M.The difference depends,in part,on the strength levelof the concrete.5.3 The conditions of manufacture,the moisture content,and other characteristics of the test specimens(see section onTest Specimens)influence the results obtained.5.4 Different computed va