ASTM_D_5298_-_16.pdf

Designation:D529816Standard Test Method forMeasurement of Soil Potential(Suction)Using Filter Paper1This standard is issued under the fixed designation D5298;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 covers laboratory filter papers aspassive sensors to evaluate the soil matric and total potential(suction),a measure of the free energy of the pore-water ortension stress exerted on the pore-water by the soil matrix(1,2).2The term potential or suction is descriptive of the energystatus of soil water.1.2 This test method controls the variables for measurementof the water content of filter paper that is in direct contact withsoil or in equilibrium with the partial pressure of water vaporin the air of an airtight container enclosing a soil specimen.Thefilter paper is enclosed with a soil specimen in the airtightcontainer until moisture equilibrium is established;that is,thepartial pressure of water vapor in the air is in equilibrium withthe vapor pressure of pore-water in the soil specimen.1.3 This test method provides a procedure for calibratingdifferent types of filter paper for use in evaluating soil matricand total potential.1.4 UnitsThe values stated in SI units are to be regardedas standard.The inch-pound units given in parentheses aremathematical conversions,which are provided for informationpurposes only and are not considered standard.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:3C114 Test Methods for Chemical Analysis of HydraulicCementD653 Terminology Relating to Soil,Rock,and ContainedFluidsD1125 Test Methods for Electrical Conductivity and Resis-tivity of WaterD2216 Test Methods 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 ConstructionD4542 Test Methods for Pore Water Extraction and Deter-mination of the Soluble Salt Content of Soils by Refrac-tometerD4753 Guide for Evaluating,Selecting,and Specifying Bal-ances and Standard Masses for Use in Soil,Rock,andConstruction Materials TestingD6836 Test Methods for Determination of the Soil WaterCharacteristic Curve for Desorption Using HangingColumn,Pressure Extractor,Chilled Mirror Hygrometer,or CentrifugeE230/E230M Specification and Temperature-ElectromotiveForce(emf)Tables for Standardized ThermocouplesE337 Test Method for Measuring Humidity with a Psy-chrometer(the Measurement of Wet-and Dry-Bulb Tem-peratures)E832 Specification for Laboratory Filter PapersE1137/E1137M Specification for Industrial Platinum Resis-tance ThermometersE2251 Specification for Liquid-in-Glass ASTM Thermom-eters with Low-Hazard Precision LiquidsE2877 Guide for Digital Contact Thermometers3.Terminology3.1 Definitions:3.1.1 For common definitions of technical terms in thisstandard,refer to Terminology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 atmospherea unit of pressure equal to 76 cm Mer-cury or 101 kPa at 0C.3.2.2 matricsuction(potential),hm(kPa)ingeohydrology/hydrogeology,matric suction is the differencebetween the pore gas pressure,ug,and the pore water pressure,uw,in soil;that is,y=ug uw,which yields a positive valuein either pressure FL2or pressure head,L.3.2.2.1 DiscussionIn most cases the pore gas is air at1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.04 on HydrologicProperties and Hydraulic Barriers.Current edition approved Nov.15,2016.Published December 2016.Originallyapproved in 1992.Last previous edition approved in 2010 as D529810.DOI:10.1520/D5298-16.2The boldface numbers in parentheses refer to a list of references at the end ofthis standard.3For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 atmospheric pressure.Matric suction is also referred to ascapillary suction,capillary pressure,and capillary potential.Water flows from a soil with low matric suction(a moist soil)to soil with a high suction(a dry soil).The term matrix shouldnot replace matric because only matric refers to the twosolid-liquid binding mechanism(adsorption and capillarity)contributing to