ASTM_C_1740_-_16.pdf

Designation:C174016Standard Practice forEvaluating the Condition of Concrete Plates Using theImpulse-Response Method1This standard is issued under the fixed designation C1740;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.Scope*1.1 This practice provides the procedure for using theimpulse-response method to evaluate rapidly the condition ofconcrete slabs,pavements,bridge decks,walls,or other plate-like structures.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.1.4 The text of this standard references notes and footnotesthat provide explanatory material.These notes and footnotes(excluding those in tables and figures)shall not be consideredas requirements of the standard.2.Referenced Documents2.1 ASTM Standards:2C125 Terminology Relating to Concrete and Concrete Ag-gregatesC1383 Test Method for Measuring the P-Wave Speed andthe Thickness of Concrete Plates Using the Impact-EchoMethodD5882 Test Method for Low Strain Impact Integrity Testingof Deep FoundationsE1316 Terminology for Nondestructive Examinations3.Terminology3.1 Definitions:3.1.1 Refer to Terminology C125 for general terms relatedto concrete.Refer to Terminology E1316 for terms related tonondestructive ultrasonic examination that are applicable tothis practice.3.2 Definitions of Terms Specific to This Standard:3.2.1 impulse-response method,na nondestructive testmethod based on the use of mechanical impact to causetransient vibration of a concrete test element,the use of abroadband velocity transducer placed on the test elementadjacent to the impact point to measure the response,and theuse of signal processing to obtain the mobility spectrum of thetest element.3.2.1.1 DiscussionFig.1 shows the testing configurationfor the impulse-response method.The hammer contains a loadcell to measure the transient impact force and a velocitytransducer is used to measure the resulting motion of the testobject(see top plots in Fig.2).In plate-like structures,theimpact results predominantly in flexural vibration of the testedelement,although other modes can be excited.Waveformsfrom the load cell and velocity transducer are converted to thefrequency domain and used to calculate the mobility spectrum,which is analyzed to obtain parameters representing the el-ements response to the impact.These parameters are used toidentify anomalous regions within the tested element.3.2.2 mobility,nratio of the velocity amplitude at the testpoint to the force amplitude at a given frequency,expressed inunits of(m/s)/N.3.2.2.1 DiscussionFor a plate-like structure,mobility is anindicator of the relative flexibility of the tested element,whichis a function of plate thickness,concrete elastic modulus,support conditions,and presence of internal defects.A highermobility indicates that the element is relatively more flexible atthat test point(1,2).33.2.3 mobility ratio,peak-mean,nthe ratio of the peakmobility value between 0 to 100 Hz to the average mobilitybetween 100 to 800 Hz3.2.3.1 DiscussionA high ratio of the peak mobility to theaverage mobility has been found to correlate with poor support1This practice is under the jurisdiction of ASTM Committee C09 on Concreteand ConcreteAggregates and is the direct responsibility of Subcommittee C09.64 onNondestructive and In-Place Testing.Current edition approved Dec.15,2016.Published January 2017.Originallyapproved in 2010.Last previous edition approved in 2010 as C174010.DOI:10.1520/C1740-16.2For 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 boldface numbers in parentheses refer to a list of references at the end ofthis standard.*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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 conditions or voids that may exist beneath concrete slabsbearing on ground(1,2).3.2.4 mobility,average,naverage of the mobility valuesfrom the mobility spectrum be