1、Designation: D7402 09 (Reapproved 2017)Standard 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 revisi
2、on. 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
3、 asphalts that dont register a positive charge mayalso be classified as cationic 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 do
4、es 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.1.4 This internatio
5、nal 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) Commit
6、tee.2. Referenced Documents2.1 ASTM Standards:2C778 Specification for Standard 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 n
7、egatively 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 pract
8、ice 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 50 C sha
9、ll be heated to 50 6 3 C in the originalsample container in a water bath or oven. The container shouldbe vented to relieve pressure. After the sample reaches 50 63 C, stir the sample to achieve homogeneity.4.3 Emulsified asphalts with viscosity testing requirementsof 25 C should be mixed or stirred
10、at 25 6 3 C in the originalsample container to achieve homogeneity.NOTE 1Emulsified asphalts with viscosity testing requirements of25 C 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. Appa
11、ratus5.1 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
12、 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 ma
13、intaining 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 Protection
14、Agency (EPA) and many state1This 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 Oct. 1, 2017. Published October 2017. Originallyapproved in 2009. Last prev
15、ious edition approved in 2009 as D7402 09. DOI:10.1520/D7402-09R17.2For 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 we
16、bsite.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
17、 International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1agencies as a hazardous material that can cause central nervoussystem, kidney, and liver damage. Mercury, or its vapor, maybe hazardous to health and corrosive to
18、materials. Cautionshould be taken when handling mercury and mercury-containing products. See the applicable product MaterialSafety Data Sheet (MSDS) for details and the EPAs website(www.epa.gov/mercury/faq.htm) for additional information.Users should be aware that selling mercury and/or mercury-cont
19、aining products in your state may be prohibited by statelaw.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 emulsif
20、ied asphalt. Tofacilitate suspension of the electrodes, insert the glass rod orequivalent between the two electrodes under the insulator.Place the ends of the glass rod or equivalent on the twoopposite top edges of the beaker. An apparatus capable ofmanual height adjustment to insulate and suspend e
21、lectrodeassembly in emulsified asphalt may be used if desired.7.3 Connect the electrodes, that have been properly cleaned(Note 2), to the DC source. The cathode (negative electrode)should be connected to the negative terminal of the currentsource. If the electrodes are connected to the current sourc
22、einternally, the negative one should be identified in black.NOTE 2New electrodes and electrodes to be reused should be cleanedin the following sequence: (1) wash with distilled water; (2) wash with asuitable asphalt solvent; (3) wash with isopropyl or ethyl alcohol; and(4) wash with distilled water.
23、7.4 Adjust the current to at least 8 mA with the variableresistor and start timing with a suitable timing device. In somecases, a higher current level may be specified, however, thecurrent used shall be reported.7.5 When the current drops to 2 mA or at the end of 30 min,whichever occurs first, disco
24、nnect the current source andgently wash the electrodes with a smooth, thin stream ofdistilled water.7.6 Observe the asphalt deposit on the electrodes.Acationicemulsified asphalt will deposit a discernible amount of asphalton the cathode (negative electrode) while the anode (positiveelectrode) will b
25、e relatively clean.Any evidence of a deposit ofasphalt on the cathode which is clearly discernible whencompared to the anode is to be considered passing.8. Report8.1 Report the following information:8.1.1 Level of current used, and8.1.2 Whether the tested emulsified asphalt passes or isnon-conclusiv
26、e as defined in 7.6.8.2 If the emulsified asphalt does not produce conclusiveresults using Method A and it is purported to be a cationicslow-setting grade, then proceed with Method B shown belowfor identification of cationic slow-set emulsified asphalt.METHOD B9. Summary of Practice9.1 A weighed amo
27、unt of washed and dried silica sand ishand mixed with a weighed amount of emulsified asphalt.Mixing time should extend until aggregate is completelycoated. The amount of cationic slow-setting grade emulsifiedasphalt in the mix should give a total mix asphalt content ofabout 5.0 %. The sample is spre
28、ad out and allowed to air curefor 24 h. The retained coating, after boiling, is determined.10. Significance and Use10.1 The conditions of the practice are designed to identifythe adequacy of a slow-setting grade of emulsified asphalt(CSS-D2397) to properly mix, coat, and adhere to a specifiedsilica
29、sand aggregate.10.2 This practice is intended to confirm the adhesiveproperties that exist between a cationic emulsified asphalt andsilica sand and the adequacy of the sample to remain coatedafter being submerged in boiling water.NOTE 3Obtaining an acceptable result utilizing Method B does notguaran
30、tee to the user that the emulsified asphalt will be compatible withother cationic emulsified asphalts. It is recommended that the user verifycompatibility of the products in some other manner prior to mixing orblending of emulsified asphalts into one storage vessel.11. Apparatus and Material11.1 Hea
31、t SourceHot plate or Bunsen burner. The use of aBunsen burner will necessitate the placement of an interfacialmaterial between the flame and beaker.11.2 Screen850-m mesh folded into a circular configu-ration with the edges folded downward, or cut a strip of850-m mesh screen approximately 25 mm by 35
32、5 mm inlength and a circular screen of the circumference of 1000-mLbeaker. Bend the strip into a circle and insert it in the bottomof the beaker. Place the circular screen on top of the strip.11.3 Glass Beaker, 1000-mL.11.4 Paper Napkin.11.5 2030 Standard Ottawa Silica Sand, as described inSpecifica
33、tion C778 (silica sand should be washed to removeimpurities prior to test).FIG. 1 Particle Charge TesterD7402 09 (2017)211.6 SpatulaA metal spatula or its equivalent, having ablade of approximately 200 mm in length.11.7 Mixing Container, 400-mL glass or metal beaker orbowl.11.8 Beaker Tongs.12. Proc
34、edure12.1 Weigh 150 g of dry silica sand into the mixingcontainer.12.2 Add 12 g of the emulsified asphalt and immediatelybegin to mix vigorously for 20 to 60 s or until silica sand iscompletely coated. (Water may be added to facilitate mixing;1.0 % is generally sufficient.)12.3 The sample should be
35、spread onto a paper napkin insuch a manner as to facilitate curing.Allow to air cure for 24 h.(Remove sample from paper napkin and break into severalpieces; observe whether sample is completely cured. If sampleis not completely cured, allow additional curing time.)12.4 Boil about 500 mL of distilled
36、 water in a 1000-mLbeaker containing 850-m mesh screen shelf. Place the coatedsilica sand in the boiling water on top of the screen.12.5 Boil for 10 min and then decant the water.12.6 Spread the sample on a level surface and observe thecoating of the mix.13. Report13.1 From the visual examination of
37、 the amount of coatedand uncoated areas in the mixture, record the retained coating,after boiling, of the total sand surface area. If the retainedcoating is in excess of 50 %, the emulsified asphalt should beconsidered as having a passing rating for classification ofslow-setting cationic emulsified
38、asphalt.13.2 Report the following information:13.2.1 Whether the emulsified asphalt has a passing orfailing rating as described in 13.1.14. Keywords14.1 asphalt emulsion; cationic emulsified asphalt; emulsi-fied asphalt; emulsion; particle chargeC1 500 F 25-V capacitor R4 meter shunt (determined by
39、type of meter used)D1 silicon diode S1 2-pole, 3-position rotary switchR147, 1-W resistor T1 12.6-V filament transformerR2 5000 potentiometer M10to10-mAmilliameterR3 6800 ,14-W resistorFIG. 2 Particle Charge Tester Circuit DiagramFIG. 3 InsulatorD7402 09 (2017)3ASTM International takes no position r
40、especting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.Thi
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42、rnational Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown
43、below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 09 (2017)4
