1、Designation:D676721Standard Test Method forPore Size Characteristics of Geotextiles by Capillary FlowTest1This standard is issued under the fixed designation D6767;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revi
2、sion.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 the determination of the poresize distribution of geotextile filters with pore sizes rangingfrom 1 to 1000 m
3、.NOTE1The accuracy of this procedure has been verified up to amaximum pore size of 500 m.Above this value,accuracy has been foundto be equipment dependent and should be verified by the user throughchecks on materials with known opening sizes.1.2 The test method measures the entire pore size distribu
4、-tion in terms of a surface analysis of specified pore sizes in ageotextile,defined in terms of the limiting diameters.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesa
5、fety 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.1.5 This international standard was developed in accor-dance w
6、ith 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.2.Referenced Documents2.1 ASTM Standards:2
7、D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD4354 Practice for Sampling of Geosynthetics and RolledErosion Control Products(RECPs)for TestingD4439 Terminology for Geosynthetics3.Terminology3.1 DefinitionsFor definitions of other terms used in thistest method,refer to Term
8、inologies D4439 and D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 bubble point pore size(O98),nthe largest effectivepore diameter detected by the sudden increase of flow rate atthe beginning of the wet test.3.2.2 pore constriction(O),ndiameter of a circle havingthe same area as the
9、smallest section of a given pore.3.2.3 pore size(Oi),ncapillary equivalent pore diameterfor which the percent of total pore diameters i in a givengeotextile based on the surface occupied by the pores is smallerthan or equal to that diameter.3.2.4 pore size distribution(PSD),npercent cumulativedistri
10、bution of the complete range of pore sizes with in a givengeotextile based on the surface occupied by the pores.3.2.5 wetting fluid,nfluid used to wet the geotextile testspecimen for the capillary porometry portion of the testmethod,that is,the“wet”test.The verb“wet”is intended tomean to completely
11、saturate the geotextile specimen with thewetting fluid thoroughly such that the entire thickness of thespecimen contains fluid with no entrained air bubbles.4.Summary of Test Method4.1 Geotextile filters have discrete pores from one side tothe other of the geotextile.The bubble point test is based o
12、n theprinciple that a wetting fluid is held in these continuous poresby capillary attraction and surface tension,and the minimumpressure required to force fluid from these pores is a functionof pore diameter.4.2 A fluid-wet geotextile will pass air when the applied airpressure exceeds the capillary
13、attraction of the fluid in the poreconstriction.Smaller pore constrictions will exhibit similarbehavior at higher pressures.The relationship between poresize and pressure has been established for the wetting fluid.4.3 By comparing the gas flow rates of both a wet and drytest at the same pressures,th
14、e percentage of the flow passingthrough the filter pores larger than or equal to the specified sizemay be calculated from the pressure-size relationship.By1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.03 on Perm
15、e-ability and Filtration.Current edition approved May 1,2021.Published May 2021.Originallyapproved in 2002.Last previous edition approved in 2020 as D6767 20a.DOI:10.1520/D6767-21.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.Fo
16、r 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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Techni
