1、Designation: D 1856 09Standard Test Method forRecovery of Asphalt From Solution by Abson Method1This standard is issued under the fixed designation D 1856; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、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 recovery by the Absonmethod of asphalt from a solution from a previously conductedextraction. The asphalt
3、 is recovered with properties substan-tially the same as those it possessed in the bituminous mixtureand in quantities sufficient for further testing.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are provided forinformation only.1.3 This standar
4、d 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
5、 Standards:2C 670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsD 2172 Test Methods for Quantitative Extraction of Bitu-men From Bituminous Paving MixturesD 2939 Test Methods for Emulsified Bitumens Used asProtective CoatingsD 4080 Specification for T
6、richloroethylene, Technical andVapor-Degreasing GradeD 6368 Specification for Vapor-Degreasing Solvents Basedon normal-Propyl Bromide and Technical Grade normal-Propyl BromideE1 Specification for ASTM Liquid-in-Glass Thermometers3. Summary of Test Method3.1 The solution of solvent and asphalt from a
7、n asphalt mixextraction is distilled under prescribed conditions to a pointwhere most of the solvent has been distilled, at which timecarbon dioxide gas is introduced into the distillation process toremove all traces of the extraction solvent. The recoveredasphalt (distillation residue) can then be
8、subjected to furthertesting as required.4. Significance and Use4.1 The asphalt should be extracted from the aggregate-asphalt mixture in accordance with Method A of Test MethodsD 2172 (centrifuge method) as there is some experimentalevidence that the recovered asphalt may have slightly lowerpenetrat
9、ion values when recovered from solutions obtainedfrom hot extraction methods.5. Apparatus5.1 Centrifuge, batch unit capable of exerting a minimumcentrifugal force of 770 times gravity or continuous unitcapable of exerting a minimum force of 3000 times gravity.5.2 Centrifuge TubesA supply of wide-mou
10、th bottles orcentrifuge tubes may be used for the batch unit. A tube asillustrated in Fig. 1 has been found satisfactory for thecontinuous unit.5.3 Distillation Assembly, as shown in Fig. 2, and consistingof the following items:5.3.1 Extraction FlasksTwo 250-ml, wide-mouth, heat-resistant flasks, on
11、e for distillation and the other for thereceiver.5.3.2 Glass TubingHeat-resistant glass tubing, having10-mm inside diameter and gooseneck shaped (as shown inFig. 2) for connecting the flask to the condenser.5.3.3 Inlet Aeration Tube,3at least 180 mm in length,having a 6-mm outside diameter with a 10
12、-mm bulb carryingsix staggered side holes approximately 1.5 mm in diameter.5.3.4 Electric Heating Mantle, with variable transformer, oilbath, or fluidized sand bath, to fit a 250-ml flask.1This method is under the jurisdiction of ASTM Committee D04 on Road andPaving Materials and is the direct respo
13、nsibility of Subcommittee D04.25 onAnalysis of Bituminous Mixtures.Current edition approved July 1, 2009. Published August 2009. Originallyapproved in 1961. Last previous edition approved in 2003 as D 1856 95a (2003).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact AST
14、M Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The sole source of supply of the apparatus known to the committee at this timeis Inlet Aeration Tube, Part No. 226, available from Wm. A. Sales
15、, Ltd., 419Harvester Court, Wheeling, Ill. 60090; request Part No. 226. If you are aware ofalternative suppliers, please provide this information to ASTM InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may atte
16、nd.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.3.5 Water-Jacketed Condenser, Allihn type, with 200-mmminimum jacket length or equivalent.5.3.6 ThermometerAn ASTM Low Distillation Ther-mometer 7E or 7F, as specified, having a ra
17、nge from 2 toFIG. 1 Centrifuge Tube ExampleFIG. 2 Distillation Assembly for Bitumen RecoveryD1856092300C or 30 to 580F, respectively, and conforming to therequirements in Specification E1.5.3.7 Gas Flowmeter,4as shown in Fig. 2, or any flowmetercapable of indicating a gas flow of up to 1000 ml/min.5
18、.3.8 Corks, No. 20, drilled as shown in Fig. 2.5.3.9 Flexible Elastomeric Tubing, resistant to chlorinatedsolvents having sufficient length and size to connect theaeration tube to flowmeter, and equipped with a pinch clamp orstopcock to close aeration tube prior to introducing carbondioxide.5.3.10 S
19、eparatory Funnel,5(Alternative Procedure, see9.3.1) 125-ml capacity.6. Reagents and Materials6.1 Carbon Dioxide GasA pressurized tank, withpressure-reducing valve or other convenient source.6.2 Solvents6.2.1 The solvent for extracting the asphalt from mixturesmay be trichloroethylene, conforming wit
20、h SpecificationD 4080.66.2.2 The solvent for extracting the asphalt from mixturesmay be Normal Propyl Bromides (nPB). This solvent shouldconform to Specification D 6368.76.2.3 The solvent for extracting the asphalt from mixturesmay be reagent grade Methylene Chloride.77. Precautions7.1 WarningThe so
21、lvent listed in 6.2 should be used onlyunder a hood or with an effective surface exhaust system in awell-ventilated area, since they are toxic to various degrees.Consult the current Threshold Limit Concentration Committeeof the American Conference of Governmental Industrial Hy-gienists for the curre
22、nt threshold limit values.7.2 These solvents in the presence of heat and moisture maybe hydrolyzed to form acids that are extremely corrosive tocertain metals, particularly when subject to contact overlengthy periods of time. Proper precautions should be taken tonot allow these solvents to remain in
23、 small quantities in theeffluent tanks of aluminum vacuum extractors.7.3 Exposure of these solvents or their vapors to hightemperatures such as contact with flames, hot glowing surfaces,or electric arcs can produce decomposition products such ashydrogen chloride. Steel drums containing these solvent
24、sshould be stored in a cool, dry location, kept tightly sealed, andopened as infrequently as possible. The hydrogen chloride indecomposed solvent may harden an asphalt during the extrac-tion and recovery test.8. Sample8.1 The sample shall consist of the solution from a previousextraction by Method A
25、 of Test Methods D 2172 of asphalt-aggregate mixture of sufficient quantity to result in 75 to 100 gof recovered bitumen. More or less quantities of bitumen maybe recovered; however, the properties of the recovered bitumenmay not be in agreement with those recovered of the afore-mentioned quantities
26、, and in case of a disagreement, 75 to 100g should be recovered.8.2 During the extraction process, it is important that all ofthe asphalt in the mixture be extracted as there could be someselective solvency of the asphalt and the harder, more viscouscomponents of the asphalt might be left in the mix
27、ture ifextraction is not carried to completion.8.3 Since heavy petroleum distillates such as mineral spiritsor kerosine will affect the properties of the recovered asphalt,it is important to avoid the use of such solvents in cleaning theextraction and recovery apparatus and use only trichloroethyl-e
28、ne for cleaning. Residues of heavy petroleum solvents on theequipment may contaminate the recovered asphalt and affect itstest properties. It is also necessary to use new filter rings, cleanfelt pads, or other uncontaminated filtering media in theextraction process to avoid contamination from a prev
29、iousextraction.8.4 Generally, the bitumen in mixtures will progressivelyharden when exposed to air, particularly if the mixtures are ina loose condition. Therefore, it is important to protect bitumi-nous mixtures from exposure to air and preferably to storethem in airtight containers at a temperatur
30、e below 0C (32F)until they can be tested. When samples of bituminous mixtureare warmed for preparing representative proportions for extrac-tion tests in accordance with Method A of Test MethodsD 2172, they should be placed in an oven in covered containersand heated to a maximum temperature of 110C (
31、230F) for theminimum time to obtain workability, but no longer than 30min. If the samples have been stored at a low temperature, theyshould be allowed to reach room temperature before placingthem in the oven.9. Procedure9.1 The entire procedure, from the start of the extraction tothe final recovery,
32、 must be completed within 8 h.9.2 Centrifuge the solution from the previous extraction fora minimum of 30 min at 770 times gravity in either bottles orcentrifuge tubes in the specified batch apparatus. If a continu-ous centrifuge is used, the extract solution shall be charged ata rate not to exceed
33、150 ml/min, while the unit is operating ata speed calculated to produce a centrifugal force of not lessthan 3000 times gravity.9.3 Concentrate the solution to about 200 ml by any primarydistillation operation using a flask large enough to hold all thesolution from the extraction. Transfer the residu
34、e from theprimary distillation flask, using several washes of solvent torinse all of the residue into the 250-ml distillation flask.4The sole source of supply of the apparatus known to the committee at this timeis The Monostat Corp. “Flowmeter” No. 9144. If you are aware of alternativesuppliers, ple
35、ase provide this information to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsibletechnical committee,1which you may attend.5The sole source of supply of the apparatus known to the committee at this timeis Kimball separatory funnel No. 29
36、028. If you are aware of alternative suppliers,please provide this information to ASTM International Headquarters. Your com-ments will receive careful consideration at a meeting of the responsible technicalcommittee,1which you may attend.6The sole source of supply of the apparatus known to the commi
37、ttee at this timeis American Conference of Governmental Industrial Hygienists, Inc. (ACGIH),1330 Kemper Meadow Dr., Cincinnati, OH 45240, (http:/www.acgih.org). If youare aware of alternative suppliers, please provide this information to ASTMInternational Headquarters. Your comments will receive car
38、eful consideration at ameeting of the responsible technical committee,1which you may attend.7It is recommended that for each new supply of the solvent a blank should be runon an asphalt of known properties.D1856093Assemble the apparatus as shown in Fig. 2, except position thebottom of the aeration t
39、ube above the surface of the solution.Continue distillation until the temperature reaches 135C(275F), at which time lower the aeration tube so that the bulbis in contact with the bottom of the flask, and introduce carbondioxide gas at a low rate (approximately 100 ml/min) toprovide agitation and pre
40、vent foaming. If foaming or bumpingoccurs, introduce carbon dioxide intermittently at the begin-ning of the distillation at a rate of 100 ml/min to prevent this.When the temperature reaches 157 to 160C (315 to 320F),increase the carbon dioxide gas flow to approximately 900mL/min. Maintain this gas f
41、low rate for 10 min while alsomaintaining the temperature of the residue in the flask at 160 to166C (320 to 330F). If, after 10 min, dripping of condensedsolvent from the delivery tube is still occurring, maintain thegas flow and temperature until 5 min after the dripping ceasesin order to flush sol
42、vent vapors from the flask. In no case shallthe time of flow of carbon dioxide gas be less than 15 min. Atthe end of this period, discontinue gas flow and heat.9.3.1 Alternative ProcedureAssemble the apparatus asshown in Fig. 2 with the separatory funnel in the thermometerhole in the cork. (It may b
43、e advantageous to insert theseparatory funnel in a separate hole drilled in the cork stopper.)Raise the aeration tube so that the bulb is above the surface ofthe solution. Fill the separatory funnel with the centrifugedsolution and open the stopcock to fill the flask approximatelyone half full of so
44、lvent mixture.Apply low heat to the flask andstart distillation. Adjust the funnel stopcock to introduce freshsolvent at a rate that will keep the flask approximately one halffull during distillation, adding additional solvent mixture to thefunnel until all solvent has been introduced into the disti
45、llationflask. Wash the solvent mixture container and funnel with freshsolvent to transfer all asphalt into the distillation flask. Con-tinue distillation until the temperature reaches 135C (275F),at which time lower the aeration tube so that the bulb is incontact with the bottom of the flask and int
46、roduce carbondioxide gas at a low rate (approximately 100 ml/min) toprovide agitation and prevent foaming. If foaming or bumpingoccurs, introduce carbon dioxide intermittently at the begin-ning of the distillation at a rate of 100 ml/min to prevent this.When the temperature reaches 157 to 160C (315
47、to 320F),increase the carbon dioxide gas flow to approximately 900mL/min. Maintain this gas flow rate for 10 min while alsomaintaining the temperature of the residue in the flask at 160 to166C (320 to 330F). If, after 10 min, dripping of condensedsolvent from the delivery tube is still occurring, ma
48、intain thegas flow and temperature until 5 min after the dripping ceasesin order to flush solvent vapors from the flask. In no case shallthe time of flow of carbon dioxide gas be less than 15 min. Atthe end of this period, discontinue the gas flow and heat.9.4 If the residue in the flask is highly v
49、iscous at 163C(325F), so that dispersion of the carbon dioxide in the residueis restricted and the recovered asphalt is expected to have apenetration at 25C (77F) of less than 30, maintain the carbondioxide gas flow and temperature for 20 to 22 min.9.5 The recovered asphalt can be heated to reliquefy andportions taken for penetration, softening point, ductility, ashcontent, and kinematic and absolute viscosity determinationsas required. Ash content determinations shall be conducted onall recovered bitumens in accordance with Test MethodsD 2939 and repo
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