1、Designation:D8281/D8281M21Standard Test Method forDetermining the Presence of Expanding Clays in Rock forErosion Control Using Ethylene Glycol1This standard is issued under the fixed designation D8281/D8281M;the number immediately following the designation indicates theyear of original adoption or,i
2、n the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the testing for and quantitativedetermination of the presence of
3、 swelling clays of the smectitegroup in rock for erosion control.The test particles areintended to be representative of erosion control rock and itsdurability.The test is appropriate for breakwater stone,armorstone,riprap and gabion sized rock materials.1.2 Ethylene glycol is one of the materials th
4、at react withswelling clays to form an organoclay complex having a largerbasal spacing than that of the clay mineral itself.Rockcontaining swelling clay of the smectite group will be expectedto undergo expansive breakdown upon soaking in ethyleneglycol.If the amount,distribution,state of expansion,a
5、ndability to take up glycol is such as to cause such breakdown tooccur,it may be expected that similar breakdown may occur ofsimilar rock samples exposed,for longer times,to wetting anddrying or freezing and thawing in a water-soaked condition inservice.1.3 The prepared size of the rock specimens ma
6、y eliminatesome of the internal features present in the gross structure.Thetest specimens may not be representative of the quality of thelarger rock samples used in construction.Careful examinationof the rock source and proper sampling are essential inminimizing this limitation.1.3.1 The test is tim
7、e intensive and requires over two weeksto complete the sample preparation,testing and analysisportions of the procedure.1.4 The use of reclaimed concrete and materials other thannatural rock is beyond the scope of this test method.1.5 UnitsThe values stated in either SI units or inch-pound units are
8、 to be regarded separately as standard.Thevalues stated in each system may not be exact equivalents;therefore,each system shall be used independently of the other.Combining values from the two systems may result in non-conformance with the standard.Reporting of test results inunits other than SI sha
9、ll not be regarded as nonconformancewith this standard.1.5.1 The gravitational system of inch-pound units is usedwhen dealing with inch-pound units.In this system,the pound(lbf)represents a unit of force(weight),while the unit for massis slugs.The slug unit is not given unless dynamic(F=ma)calculati
10、ons are involved.1.5.2 The SI units presented for apparatus are substitutionsof the inch-pound units,other similar SI units should beacceptable providing they meet the technical requirementsestablished by the inch-pound apparatus.1.5.3 It is common practice in the engineering/constructionprofession
11、to concurrently use pounds to represent both a unitof mass(lbm)and force(lbf).This practice implicitly com-bines two separate systems of units:the absolute and thegravitational systems.It is scientifically undesirable to com-bine the use of two separate sets of inch-pound units within asingle standa
12、rd.As stated,this standard includes the gravita-tional system of inch-pound units and does not use/present theslug unit for mass.However,the use of balances or scalesrecording pounds of mass(lbm)or recording density in lbm/ft3shall not be regarded as nonconformance with this standard.1.5.4 Calculati
13、ons are done using only one set of units;either SI or gravitational inch pound.Other units are permis-sible provided appropriate conversion factors are used tomaintain consistency of units throughout the calculations,andsimilar significant digits or resolution,or both are maintained.1.6 All observed
14、 and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026,unless superseded by this standard.1.6.1 For purposes of comparing measured or calculatedvalue(s)with specified limits,the measured or calculatedvalue(s)shall be rounded to the near
15、est decimal or significantdigits in the specified limits.1.6.2 The procedures used to specify how data are collected/recorded or calculated,in this standard are regarded as theindustry standard.In addition,they are representative of thesignificant digits that generally should be retained.The proce-d
16、ures 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 to1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.17 on Rock for ErosionControl.Current edition approved May 1,2021.Published May 2021.DOI:10.1520/D8281_D8281M-21.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohock
