1、Designation:D464308Standard Test Method forDetermination of Water(Moisture)Content of Soil byMicrowave Oven Heating1This standard is issued under the fixed designation D4643;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of
2、 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 outlines procedures
3、 for determining thewater(moisture)content of soils by incrementally drying soilin a microwave oven.1.2 This test method can be used as a substitute for TestMethod D2216 when more rapid results are desired to expediteother phases of testing and slightly less accurate results areacceptable.1.3 When q
4、uestions of accuracy between this test methodand Test Method D2216 arise,Test Method D2216 shall be thereferee method.1.4 This test method is applicable for most soil types.Forsome soils,such as those containing significant amounts ofhalloysite,mica,montmorillonite,gypsum or other hydratedmaterials,
5、highly organic soils,or soils in which the pore watercontains dissolved solids(such as salt in the case of marinedeposits),this test method may not yield reliable water contentvalues.1.5 The values stated in SI units are to be regarded as thestandard.No other units of measurement are included in thi
6、stest method.1.6 Refer to Practice D6026 for guidance concerning the useof significant figures.This is especially important if the watercontent will be used to calculate other relationships such asmoist mass to dry mass or vice versa,wet unit weight to dryunit weight or vice versa,and total density
7、to dry density orvice versa.For example,if four significant digits are requiredin any of the above calculations,then the water content has tobe recorded to the nearest 0.1%.This occurs since 1 plus thewater content(not in percent)will have four significant digitsregardless of what the value of the w
8、ater content is;that is,1plus 0.1/100=1.001,a value with four significant digits.While,if three significant digits are acceptable,then the watercontent can be recorded to the nearest 1%.1.7 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is there
9、sponsibility 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.See Section 7.2.Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil,Rock,and ContainedFluidsD2216 Test Methods
10、 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 ConstructionD4753 Guide for Evaluating,Selecting,and Specifying Bal-ances and Sta
11、ndard Masses for Use in Soil,Rock,andConstruction Materials TestingD6026 Practice for Using Significant Digits in GeotechnicalData3.Terminology3.1 Definitions:3.1.1 All definitions are in accordance with TerminologyD653.3.2 Definitions of Terms Specific to This Standard:3.2.1 microwave heatinga proc
12、ess by which heat is in-duced within a material due to the interaction between dipolarmolecules of the material and an alternating,high frequencyelectric field.Microwaves are electromagnetic waves with 1mm to 1 m wavelengths.3.2.2 water(moisture)contentthe ratio,expressed as apercentage,of the mass
13、of“pore”or“free”water in a givenmass of soil to the mass of the solid particles.1This 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 Jan.1,2008.Publis
14、hed February 2008.Originallyapproved in 1987.Last previous edition approved in 2000 as D4643 00.2For 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 Su
15、mmary page onthe ASTM website.DOI:10.1520/D4643-08.*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 4.Summary of Test Method4.1 A moist soil specimen is placed in a suitable
16、containerand its mass is determined.It is then placed in a microwaveoven,subjected to an interval of drying,and removed from theoven and its new mass is determined.This procedure isrepeated until the mass becomes nearly constant.4.2 The difference between the mass of the moist specimenand the dried specimen is used as the mass of water originallycontained in the specimen.The water content is determined bydividing the mass of water by the dry mass of soil,multipliedby 100.For a given soil and sam
