1、Designation: D 1856 95a (Reapproved 2003)Standard 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
2、 of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 conductedext
3、raction. The asphalt is recovered with properties substan-tially the same as those it possessed in the bituminous mixtureand in quantities sufficient for further testing.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility
4、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:2C 670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsD
5、 96 Test Methods for Water and Sediment in Crude Oil byCentrifuge Method (Field Procedure)3D 2172 Test Methods for Quantitative Extraction of Bitu-men from Bituminous Paving MixturesD 2939 Test Methods for Emulsified Bitumens Used asProtective CoatingsE 1 Specification for ASTM Liquid-in-Glass Therm
6、ometers3. Summary of Test Method3.1 The solution of solvent and asphalt from a prior extrac-tion is distilled under prescribed conditions to a point wheremost of the solvent has been distilled, at which time carbondioxide gas is introduced into the distillation process to removeall traces of the ext
7、raction solvent. The recovered asphalt(distillation residue) can then be subjected to further testing asrequired.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 experi
8、mentalevidence that the recovered asphalt may have slightly lowerpenetration 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,4or continuous unitcapable of exerting a mi
9、nimum force of 3000 times gravity.(The apparatus specified in Test Methods D 96 may also beused.)5.2 Centrifuge TubesA supply of wide-mouth bottles orcentrifuge tubes as shown in Fig. 1 or Fig. 2 of Test MethodsD 96.5.3 Distillation Assembly, as shown in Fig. 1, and consistingof the following items:
10、5.3.1 Extraction FlasksTwo 250-ml, wide-mouth, heat-resistant flasks, one 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. 1) for connecting the flask to the condenser.5.3.3 Inlet Aeration
11、Tube,5at least 180 mm in length,having a 6-mm outside diameter with a 10-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.5.3.5 Water-Jacketed Condenser, Allihn t
12、ype, with 200-mmminimum jacket length or equivalent.5.3.6 ThermometerAn ASTM Low Distillation Ther-mometer 7E or 7F, as specified, having a range from 2 to300C or 30 to 580F, respectively, and conforming to therequirements in Specification E 1.1This method is under the jurisdiction of ASTM Committee
13、 D04 on Road andPaving Materials and is the direct responsibility of Subcommittee D04.25 onAnalysis of Bituminous Mixtures.Current edition approved Dec. 1, 2003. Published January 2004. Originallyapproved in 1961. Last previous edition approved in 1995 as D 1852 95a.2For referenced ASTM standards, v
14、isit 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.3Withdrawn.4An “International” No. 2 centrifuge operating at 1900 rpm or an “SMMContinuous Cen
15、trifuge” exerting a force of 3000 times gravity at 9000 rpm, havebeen found satisfactory for this purpose.5Inlet Aeration Tube, Part No. 226, available from Wm. A. Sales, Ltd., 419Harvester Court, Wheeling, Ill. 60090; request Part No. 226.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box
16、 C700, West Conshohocken, PA 19428-2959, United States.5.3.7 Gas Flowmeter,6as shown in Fig. 1, or any flowmetercapable of indicating a gas flow of up to 1000 ml/min.5.3.8 Corks, No. 20, drilled as shown in Fig. 1.5.3.9 Flexible Elastomeric Tubing, resistant to chlorinatedsolvents having sufficient
17、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 Separatory Funnel,7(Alternative Procedure, see9.3.1) 125-ml capacity.6. Reagents and Materials6.1 Carbon Dioxide GasA pressurized tank
18、, withpressure-reducing valve or other convenient source.6.2 The solvent for extracting the asphalt from mixturesshould be reagent grade trichloroethylene.87. Precautions7.1 CautionThe solvent listed in 6.2 should be used onlyunder a hood or with an effective surface exhaust system in awell-ventilat
19、ed area, since it is toxic to some degree asindicated below:Solvent TLV, ppmASTEL, ppmBTrichloroethylene 50 200_AThreshold limit value (TLV) as established by the American Conference ofGovernmental Industrial Hygienists (ACGIH), Bldg. D-7, 6500 Glenway Ave.,Cincinnati, OH 45211-4438. 1990/1991 value
20、s. The TLV is a time weightedaverage for an exposure period of 8 h per day, 5 days per week.BShort term exposure limit (STEL) as established by ACGIH. 1990/1991 values.8. Sample8.1 The sample shall consist of the solution from a previousextraction by Method A of Test Methods D 2172 of asphalt-aggreg
21、ate 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, and in case of a disagreement, 75 to 10
22、0g 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 mixture ifextraction is not carried to compl
23、etion.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-ene for cleaning. Residues of heavy petrol
24、eum 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 previousextraction.8.4 Generally, the bitumen
25、 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 temperature below 0C (32F)until they can be tested.
26、 When samples of bituminous mixture6The Monostat Corp. “Flowmeter” No. 9144 has been found satisfactory for thispurpose.7Kimball separatory funnel No. 29028 has been found satisfactory for thispurpose.8Trichloroethylene, Technical Grade, Type I, Federal Specification O-T-634,latest revision may be u
27、sed, but it is recommended that for each new supply of thesolvent a blank should be run on an asphalt of known properties.FIG. 1 Distillation Assembly for Bitumen RecoveryD 1856 95a (2003)2are warmed for preparing representative proportions for extrac-tion tests in accordance with Method A of Test M
28、ethodsD 2172, they should be placed in an oven in covered containersand heated to a maximum temperature of 110C (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 pla
29、cingthem in the oven.9. Procedure9.1 The entire procedure, from the start of the extraction tothe final recovery, 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 ba
30、tch apparatus. If a continu-ous centrifuge is used, the extract solution shall be charged ata rate not to exceed 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 primaryd
31、istillation operation using a flask large enough to hold all thesolution from the extraction. Transfer the residue from theprimary distillation flask, using several washes of solvent torinse all of the residue into the 250-ml distillation flask.Assemble the apparatus as shown in Fig. 1, except posit
32、ion thebottom of the aeration tube 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/m
33、in) 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 to 320F),increase the carbon dioxide gas flow to approximately
34、 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, maintain thegas flow and temperature until 5 min after the dripp
35、ing 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 gas flow and heat.9.3.1 Alternative ProcedureAssemble the apparatus asshown in Fig. 1 with the separatory funnel in the thermom
36、eterhole in the cork. (It may be 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 a
37、pproximatelyone half full of solvent 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 ha
38、s been introduced into the distillationflask. 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
39、 the bottom of the flask and introduce 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 tempe
40、rature reaches 157 to 160C (315 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 deli
41、very tube is still occurring, maintain 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
42、residue in the flask is highly viscous 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 a
43、sphalt 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 reported with
44、other test data on the recoveredasphalt. Ash contents of recovered asphalts greater than 1 %may affect the accuracy of the penetration, ductility, softeningpoint, or viscosity tests.NOTE 1Determination of the weight of asphalt recovered serves as acheck to assure that all of the solvent has been rem
45、oved when this weightis compared with the weight of asphalt extracted as determined by TestMethods D 2172. The weight of the recovered asphalt should be correctedfor the ash content determined.10. Precision and Bias10.1 PrecisionData from the AMRL9proficiency sampledatabase from 1974 to 1992 was ana
46、lyzed to develop estimatesof test precision.10The results of the analysis are summarizedbelow. The grades of asphalt binders included in the analysisconsisted of AC-5, AC-10, AC-15, AC-20, AC-30, AC-40,AR-2000, and AR-4000. The precision estimates providedapply to unaged asphalt binder having physic
47、al test propertieswithin the following ranges:Penetration at 25C (77F) 29 to 181Kinematic viscosity at 135C (275F), cSt 200 to 720Viscosity at 60C (140F), P 520 to 532010.1.1 Single-Operator PrecisionThe figures given inColumn 2 are the coefficients of variation that have been foundto be appropriate
48、 for the tests and conditions described inColumn 1. When performed by the same operator on the samesample in the same laboratory using the same apparatus, thedifference in the results of two properly conducted tests,9These numbers represent, respectively, the (1s %) and (d2s %) limits asdescribed in
49、 ASTM Practice C 670.10The data is included in a research report available from ASTM Headquarters.Request RR: D04-1008.D 1856 95a (2003)3expressed as a percent of their mean, shall not exceed thefigures given in Column 3.Test IndexCoefficient ofVariation(percent of mean)12Acceptable Range ofTwo Results(percent of mean)12Single-Operator Precision:Penetration at 25C(77F)11 30Kinematic viscosity at135C (275F), cSt926Viscosity at 60C(140F), P18 5110.1.2 Multilaboratory PrecisionThe figures given inColumn 2 are the coefficients of va
