1、Designation: D 7402 09Standard Practice forIdentifying Cationic Emulsified Asphalts1This standard is issued under the fixed designation D 7402; 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
2、parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This practice is used to identify cationic emulsifiedasphalts. P
3、ositively 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
4、 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 regula
5、tory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 778 Specification for Standard SandD 2397 Specification for Cationic Emulsified AsphaltE1 Specification for ASTM Liquid-in-Glass Thermometers3. Significance and Use3.1 Cationic emulsified asphalts are identified by the migra-
6、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 ag
7、gre-gate or sand. This practice will aid in identifying a cationic typeof emulsified asphalt as defined by Specification D 2397.4. Sample Conditioning for Testing4.1 All emulsified asphalts shall be properly stirred toachieve homogeneity before testing.4.2 All emulsified asphalts with viscosity test
8、ing 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 sh
9、ould be mixed or stirred at 25 6 3C in the originalsample container to achieve homogeneity.NOTE 1Emulsified 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
10、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 InsulatorPolytetrafluo
11、roethylene 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 Wat
12、er 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 E1or equivalent thermometricdevice.6. Hazards6.1 WarningMercury has been designated by the UnitedStates Envi
13、ronmental Protection Agency (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. Se
14、e the applicable product Material Safety DataSheet (MSDS) for details and EPAs website (www.epa.gov/1This 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 Ju
15、ne 1, 2009. Published July 2009.2For 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.1Copyright ASTM International
16、, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.mercury/faq.htm) for additional information. Users should beaware that selling mercury and/or mercury containing productsinto your state may be prohibited by state law.7. Procedure7.1 Prepare the emulsified asphalt
17、 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
18、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 electrodeassembly in emulsified asphalt may be used if desired.7.3 Connect the electrodes, that have been p
19、roperly 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 sourceinternally, the negative one should be identified in black.NOTE 2New electrodes and electrodes to be reus
20、ed 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.7.4 Adjust the current to at least 8 mA with the variableresistor and start timing with a suitable timing
21、device. In somecases, a higher current levels 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, disconnect the current source andgently wash the electrodes with a smooth, thin stream ofdistilled water.7.6 O
22、bserve the asphalt deposit on the electrodes.Acationicemulsified asphalt will deposit a discernible amount of asphalton the cathode (negative electrode) while the anode (positiveelectrode) will be relatively clean.Any evidence of a deposit ofasphalt on the cathode which is clearly discernible whenco
23、mpared 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-conclusive as defined in 7.6.8.2 If the emulsified asphalt does not produce conclusiveresults using Method A and i
24、t is purported to be a cationicslowsetting grade, then proceed with Method B shown belowfor Identification of Cationic SlowSet Emulsified AsphaltMETHOD B9. Summary of Practice9.1 A weighed amount of washed and dried silica sand ishand mixed with a weighed amount of emulsified asphalt.Mixing time sho
25、uld 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 spread out and allowed to air curefor 24 h. The retained coating, after boiling, is determined.10. Significance
26、and Use10.1 The conditions of the practice are designed to identifythe adequacy of a slow-setting grade of emulsified asphalt(CSS-D 2397) to properly mix, coat, and adhere to a specifiedsilica sand aggregate.10.2 This practice is intended to confirm the adhesiveproperties that exist between a cation
27、ic 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 notguarantee to the user that the emulsified asphalt will be compatible withother cationic emulsified asphalts. It i
28、s 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 Heat SourceHot plate or Bunsen burner. The use ofa Bunsen burner will necessitate the placement of an interfac
29、ialmaterial 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 of 850 mmesh screen approximately 25 mm by 355 mm in length and acircular screen of the circumference of 1000-mL beaker. Bendthe strip into a circle and
30、 insert it in the bottom of 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 inSpecification C 778 (silica sand should be washed to removeimpurities prior to test).11.6 SpatulaA metal spatula or
31、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. Procedure12.1 Weigh 150 g of dry silica sand into the mixingcontainer.FIG. 1 Particle Charge TesterD740209212.2 Add 12 g of the emulsified asphalt and imme
32、diatelybegin to mix vigorously for 20 to 60 seconds or until silica sandis completely coated. (Water may be added to facilitate mixing;1.0 % is generally sufficient.)12.3 The sample should be spread onto a paper napkin insuch a manner as to facilitate curing. Allow to air cure for 24hours. (Remove s
33、ample from paper napkin and break intoseveral pieces; observe whether sample is completely cured. Ifsample is not completely cured, allow additional curing time.)12.4 Boil about 500 mL of distilled water in a 1000-mLbeaker containing 850 m mesh screen shelf. Place the coatedsilica sand in the boilin
34、g water on top of the screen.12.5 Boil for 10 minutes 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 the amount of coatedand uncoated areas in the mixture, record the retained coating,after boiling,
35、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 asphalt.13.2 Report the following information:13.2.1 Whether the emulsified asphalt has a passing o
36、rfailing rating as described in 13.1.14. Keywords14.1 asphalt emulsion; cationic emulsified asphalt; emulsi-fied asphalt; emulsion; particle chargeASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users o
37、f 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.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every fiv
38、e years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical c
39、ommittee, 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 below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA
40、 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).C1500 F 25-V capacitor R4meter shunt (determined by type of meter used)D1silicon diode S12-pole, 3-position rotary switchR147 V, 1-W resistor T112.6-V filament transformerR25000 V potentiometer M10 to 10-mA milliameterR36800 V,14-W resistorFIG. 2 Particle Charge Tester Circuit DiagramFIG. 3 InsulatorD7402093
