ASTM_D_6276_-_99a.pdf

Designation:D 6276 99aStandard Test Method forUsing pH to Estimate the Soil-Lime Proportion Requirementfor Soil Stabilization1This standard is issued under the fixed designation D 6276;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method provides a means for estimating thesoil-lime proportion requirement for stabilization of a soil.Thistest method is performed on soil passing the 425-m(No.40)sieve.The optimum soil-lime proportion for soil stabilization isdetermined by tests of specific characteristics of stabilized soilsuch as unconfined compressive strength or plasticity index.1.2 Some highly alkaline by-products(lime kiln dust,ce-ment kiln dust,and so forth)have been successfully used tostabilize soil.This test method is not intended for thesematerials and any such product would need to be tested forspecific characteristics as indicated in 1.1.1.3 This test method is used to determine the lowestpercentage of lime that results in a soil-lime pH of 12.4.1.4 Lime is not an effective stabilizing agent for all soils.Some soil components such as sulfates,phosphates,organics,and so forth can adversely affect soil-lime reactions and mayproduce erroneous results using this test method.1.5 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:C 51 Terminology Relating to Lime and Limestone(as usedby the industry)2C 977 Specification for Quicklime and Hydrated Lime forSoil Stabilization2D 421 Practice for Dry Preparation of Soil Samples forParticle-Size Analysis and Determination of Soil Con-stants3D 653 Terminology Relating to Soil,Rock,and ContainedFluids3D 1193 Specification for Reagent Water4D 1293 Test Methods for pH of Water4D 2216 Test Method for Laboratory Determination of Water(Moisture)Content of Soil and Rock3D 3740 Practice for Minimum Requirements for AgenciesEngaged in the Testing and/or Inspection of Soil and Rockas Used in Engineering Design and Construction3D 4753 Specification for Evaluating,Selecting,and Speci-fying Balances and Scales for Use in Testing Soil,Rock,and Related Construction Materials3E 11 Specification for Wire-Cloth Sieves for Testing Pur-poses5E 145 Specification for Gravity-Convection and Forced-Ventilation Ovens53.Terminology3.1 Definitions:3.2 Refer to Terminology C 51 for definitions of termsrelating to lime.3.3 Refer to Terminology D 653 for terms relating to soil.3.4 Definitions of Terms Specific to This Standard:3.4.1 buffer solutiona solution of specific pH value usedto calibrate the pH meter.3.4.2 free limelime in a soil-lime mixture that has notdissociated into calcium and hydroxyl ions.3.4.3 hydrated limelime that is predominately calciumhydroxide(Ca(OH)2)or a mixture of calcium hydroxide andmagnesiumoxide(MgO)ormagnesiumhydroxide(Mg(OH)2).3.4.4 limea general term which,for the purpose of thistest method,includes hydrated lime and quicklime.3.4.5 lime contentthe ratio expressed as a percentage ofthe mass of lime to the dry mass of soil.3.4.6 lime stabilizationaddition of lime to a soil in suffi-cient quantities to promote long-term pozzolanic reactions thatresult in strength gain and permanent improvement in stability.Textural improvement alone,such as reduced plasticity,isoften referred to as“modification.”Modification can be ef-fected by lime addition rates less than those required forstabilization and may not be permanent.3.4.7 pHthe negative logarithm of the effective hydrogen-ion concentration or hydrogen-ion activity,in gram equivalentsper litre.The pH values range from 0 to 14;where pH 71This test method is under the jurisdiction of ASTM Committee D-18 on Soiland Rock and is the direct responsibility of Subcommittee D18.15 on Stabilizationand Admixtures.Current edition approved June 10,1999.Published September 1999.Originallypublished as D 6276 98.Last previous edition D 6276 99.2Annual Book of ASTM Standards,Vol 04.01.3Annual Book of ASTM Standards,Vol 04.08.4Annual Book of ASTM Standards,Vol 11.01.5Annual Book of ASTM Standards,Vol 14.02.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.represents neutrality,pH values less than 7 indicate increasingacidity,and pH values greater than 7 indicate increasingalkalinity.3.4.8 quicklimelime that is predominately calcium oxide(CaO)or calcium oxide in association with magnesium oxide(MgO).3.4.9 stabilizationa process to improve the engineeringproperties of soils at a site.4.Summary of Test Method4.1 A series of specimens is prepared containing a range ofpercentag