ASTM_D_8153_-_22.pdf

Designation:D815322Standard Test Method forDetermination of Soil Water Contents Using a DielectricPermittivity Probe1This standard is issued under the fixed designation D8153;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.Scope1.1 This test method describes the procedures for measuringthe water mass per unit volume of soil and soil-aggregate byuse of an in situ permittivity probe.Measurements are taken ata depth beneath the surface of the soil determined by the designof the probe.1.1.1 For limitations see Section 6 on Interferences.1.2 The permittivity probe is inserted into a hole drilled orpunched into the soil being measured.As its name indicates,the probe measures the dielectric permittivity of the soil intowhich it is placed.Two electrodes,connected to an oscillatingcircuit,are mounted a predetermined distance apart.Theseelectrodes act as the plates of a capacitor,with the soil betweenthe plates forming the capacitor dielectric.1.2.1 The probe circuit creates an oscillating electric field inthe soil.Changes in the dielectric permittivity of the soil areindicated by changes in the circuits operating frequency.Sincewater has a much higher dielectric constant(80)than thesurrounding soil(typically around 4),the water content can berelated by a mathematical function to the change in dielectricpermittivity,and,consequently,the changes in the circuitsoperating frequency.1.2.2 The construction,deployment,and operating principleof the device described in this test method differ from othermethods that measure the dielectric constant,bulk electricalconductivity,complex impedance,or electromagnetic imped-ance(see Test Methods D6780/D6780M,D7698,and D7830/D7830M)of the soil and relate the results to water mass perunit volume and/or water content.1.2.3 The water content of the soil measured by the permit-tivity probe is the volumetric water content,expressed as theratio of the volume of water to the total volume occupied by thesoil.This quantity is often converted,and displayed,by theprobe in units of mass of water per volume of soil,or watermass per unit volume.This conversion is performed bymultiplying the water content(in volume of water per volumeof soil)by the density of water.1.3 Water content most prevalent in engineering and con-struction activities is known as the gravimetric water content,and is the ratio of the mass of the water in pore spaces to thetotal mass of solids,expressed as a percentage.To determinethis quantity,the bulk density of the soil under measurementmust also be determined.1.4 UnitsThe values stated in SI units are to be regardedas the standard.Reporting the test results in units other than SIshall not be regarded as nonconformance with this standard.1.5 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.5.1 For purposes of comparing,a measured or calculatedvalue(s)with specified limits,the measured or calculatedvalue(s)shall be rounded to the nearest decimal or significantdigits in the specified limits.1.5.2 The procedures used to specify how data are collected/recorded and calculated in this standard are regarded as theindustry standard.In addition,they are representative of thesignificant digits that should generally 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 com-mensurate with these considerations.It is beyond the scope ofthis standard to consider significant digits used in analysismethods for engineering design.1.6 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.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 June 1,2022.Published July 2022.DOI:10.1520/D8153-22.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally rec