ASTM_D_4373_-_14.pdf

Designation:D437314Standard Test Method for Rapid Determination ofCarbonate Content of Soils1This standard is issued under the fixed designation D4373;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 test method covers the determination of carbonatecontent of soils and soft rock which can be readily brokendown by mechanical effort.It is a gasometric method that usesa simple portable apparatus.Results should be clearly stated asthe calcite equivalent in percent because different carbonatespecies cover a wide range of percent calcite equivalent asshown below for a number of carbonates:SpeciesCationCalciteEquivalent,%MagnesiteMg117.0DolomiteCa,Mg108.6CalciteCa100.0AragoniteCa100.0RhodocrositeMn87.1SideriteFe86.4SmithsoniteZn79.8WitheriteBa50.7CerrusitePb37.5For example,a 100%dolomite would be expected to yield108.6%calcite equivalent while 100%siderite would yieldonly 86.4%calcite equivalent.Calcite and aragonite reactionswill typically complete within about 10 minutes.This methoddoes not distinguish between the carbonate species and suchdetermination must be made using quantitative chemical analy-sis methods such as atomic absorption.1.2 UnitsThe values stated in SI units are to be regardedas the standard.1.3 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.3.1 The procedures used to specify how data are collected/recorded or calculated,in this standard are regarded as theindustry standard.In addition,they are representative of thesignificant digits that generally should be retained.The proce-dures used do not consider material variation,purpose forobtaining the data,special purpose studies,or any consider-ations for the users objectives;and it is common practice toincrease or reduce significant digits of reported data to becommensurate with these considerations.It is beyond the scopeof this standard to consider significant digits used in analyticalmethods for engineering design.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 specificprecaution statements,see Section 8.2.Referenced Documents2.1 ASTM Standards:2C25 Test Methods for Chemical Analysis of Limestone,Quicklime,and Hydrated LimeD653 Terminology Relating to Soil,Rock,and ContainedFluidsD3042 Test Method for Insoluble Residue in CarbonateAggregatesD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4753 Guide for Evaluating,Selecting,and Specifying Bal-ances and Standard Masses for Use in Soil,Rock,andConstruction Materials TestingD6026 Practice for Using Significant Digits in GeotechnicalDataE11 Specification for Woven Wire Test Sieve Cloth and TestSievesE145 Specification for Gravity-Convection and Forced-Ventilation Ovens3.Terminology3.1 DefinitionsFor definitions of common technical termsused in this standard,refer to Terminology D653.4.Summary of Test Method4.1 The carbonate content(calcite equivalent)of soil isdetermined by treating a 1-g dried soil specimen with hydro-chloric acid(HCl)in an enclosed reaction cylinder(reactor).1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.06 on Physical-ChemicalInteractions of Soil and Rock.Current edition approved May 1,2014.Published June 2014.Originallyapproved in 1984.Last previous edition approved in 2007 as D4373 02(2007).DOI:10.1520/D4373-14.2For 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 Carbon dioxide(CO2)gas is evolved during the reactionbetween the acid and carbonate fraction of the specimen.Theresulting pressure generated in the closed reactor is propor-tional(see Fig.1)to the calcite equivalent of the specimen.This pressure is measured with a suitable pressure gauge,orequivalent pressure-measuring device,that is pre-calibratedwith reagent grade calcium carbonate.5.Significance and Use5.1 This test method is used to determine the presence andquantity of carbonate in a soil specimen in terms of the calciteequivalent.The method is generally intended for use as anindex of approximate carbonate