ASTM_D_7402_-_09.pdf

Designation:D740209Standard Practice forIdentifying Cationic Emulsified Asphalts1This standard is issued under the fixed designation D7402;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 practice is used to identify cationic emulsifiedasphalts.Positively charged particles are classified as cationic.Emulsified asphalts that dont register a positive charge mayalso be classified as cotionic slow-setting if they coat a specifictype of negatively charged silica sand.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 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:2C778 Specification for SandD2397 Specification for Cationic Emulsified AsphaltE1 Specification for ASTM Liquid-in-Glass Thermometers3.Significance and Use3.1 Cationic emulsified asphalts are identified by the migra-tion of the particles to a negatively charged electrode(cathode)by means of a direct current.Aggregates and sands used inconjunction with emulsified asphalts are often predominantlyeither negatively or positively charged.Emulsified asphaltsshould be selected to be compatible with the available aggre-gate or sand.This practice will aid in identifying a cationic typeof emulsified asphalt as defined by Specification D2397.4.Sample Conditioning for Testing4.1 All emulsified asphalts shall be properly stirred toachieve homogeneity before testing.4.2 All emulsified asphalts with viscosity testing require-ments of 50C shall be heated to 50 6 3C in the originalsample container in a water bath or oven.The container shouldbe vented to relieve pressure.After the sample reaches 50 63C,stir the sample to achieve homogeneity.4.3 Emulsified asphalts with viscosity testing requirementsof 25C should be mixed or stirred at 25 6 3C in the originalsample container to achieve homogeneity.NOTE1Emulsified asphalts with viscosity testing requirements of25C may be heated and stirred as specified in 4.2 if necessary.In theevent the 4.2 method is used,the sample should be cooled to 25 6 3Cbefore testing.METHOD A5.Apparatus5.1 Current Source,of 12-V DC,a milliammeter,and avariable resistor(see Figs.1 and 2).5.2 ElectrodesTwo stainless steel plates,approximately25 mm by 100 mm insulated from each other and rigidly heldparallel 12.5 6 0.5 mm apart(see Fig.3).5.3 InsulatorPolytetrafluoroethylene resin square rod,vir-gin electrical grade,12.5 6 0.5 mm thick(see Fig.3)5.4 Glass Beaker,250 mL.5.5 Glass Rod,approximately 100 mm long and 6 mm thickor other suitable material or device that is capable of insulatingand suspending the electrode assembly in emulsified asphalt.5.6 Water Bath,capable of maintaining the required testingtemperature within the limits specified in this test method.5.7 Thermometer,ASTM 19C or 19F conforming to therequirements of Specification E1 or equivalent thermometricdevice.6.Hazards6.1 WarningMercury has been designated by the UnitedStates Environmental ProtectionAgency(EPA)and many stateagencies as a hazardous material that can cause central nervoussystem,kidney and liver damage.Mercury,or its vapor,may behazardous to health and corrosive to materials.Caution shouldbe taken when handling mercury and mercury containingproducts.See the applicable product Material Safety DataSheet(MSDS)for details and EPAs website(www.epa.gov/mercury/faq.htm)for additional information.Users should be1This practice is under the jurisdiction of ASTM Committee D04 on Road andPaving Materials and is the direct responsibility of Subcommittee D04.42 onEmulsified Asphalt Test.Current edition approved June 1,2009.Published July 2009.DOI:10.1520/D7402-09.2For 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 Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 aware that selling mercury and/or mercury containing productsinto your state may be prohibited by state law.7.Procedure7.1 Prepare the emulsified asphalt to be tested as shown inSection 4.7.2 Pour the emulsified asphalt to be tested into the 250-mLbeaker to a height that will allow the electrodes to besuspended approximately 25 mm in the emulsified asphalt.Tofacilitate suspension of the electrodes,insert the glass rod orequivalent between the two electrodes under the insulator.Place the ends of