AASHTO R 59-2011 Standard Practice for Recovery of Asphalt Binder from Solution by Abson Method.pdf

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1、Standard Practice for Recovery of Asphalt Binder from Solution by Abson Method AASHTO Designation: R 59-11 (2015)1ASTM Designation: D1856-09 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-2c R 59-1 AASHTO Standard

2、 Practice for Recovery of Asphalt Binder from Solution by Abson Method AASHTO Designation: R 59-11 (2015)1ASTM Designation: D1856-09 1. SCOPE 1.1. This practice covers the recovery, by the Abson Method, of asphalt binder from a previously conducted extraction with reagent-grade trichloroethylene or

3、reagent-grade methylene chloride (Note 1). The asphalt binder is recovered with properties substantially the same as those it possessed in the asphalt mixture and in quantity sufficient for further testing. Note 1Trichloroethylene conforming to ASTM D4080 or technical-grade methylene chloride may be

4、 used, but it is recommended that for each new supply of the solvent a “blank” recovery as described below be performed on an asphalt binder of known properties. Certain epoxy resins in some non-reagent-grade solvents may affect the properties of the recovered binder. In case of dispute, reagent gra

5、de should be used. 1.2. Blank DeterminationsIntroduce about 75 to 100 g of asphalt binder into a 2000-mL (68-oz) flask; add about 800 mL (27 oz) of solvent to dissolve the asphalt. Allow the solution to stand for about 4 h; concentrate the solution by distillation to about 200 mL (6.8 oz), and then

6、recover the asphalt binder. The total elapsed time, from when the solvent is added to the time the recovery test is completed, is about 7 h. 1.3. The values stated in SI units are to be regarded as the standard. 1.4. This standard does not purport to address all of the safety concerns, if any, assoc

7、iated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: R 16, Regulatory Information for Chemicals Used in AAS

8、HTO Tests T 111, Mineral Matter or Ash in Asphalt Materials T 164, Quantitative Extraction of Asphalt Binder from Hot Mix Asphalt (HMA) 2.2. ASTM Standards: C670, Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials D4080, Standard Specification f

9、or Trichloroethylene, Technical and Vapor-Degreasing Grade E1, Standard Specification for ASTM Liquid-in-Glass Thermometers 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2c R 59-2 AASHTO 3. SUMMARY

10、OF METHOD 3.1. The solution of solvent and asphalt binder from a prior extraction is distilled under prescribed conditions to a point where most of the solvent has been distilled, at which time carbon dioxide gas is introduced into the distillation process to remove all traces of the extraction solv

11、ent. The recovered asphalt binder (distillation residue) can then be subjected to further testing as required. 4. SIGNIFICANCE AND USE 4.1. The asphalt binder should be extracted from the asphalt mixture in accordance with Method A or E (Note 2) of T 164, as there is some experimental evidence that

12、the recovered asphalt binder may have slightly lower penetration values when recovered from solutions obtained from hot extraction methods. Note 2Equipment in Method E of T 164 can be modified by a vacuum trap attached to the top of the “end-point” site tube to collect the extract. 5. APPARATUS 5.1.

13、 CentrifugeBatch unit capable of exerting a minimum centrifugal force of 770 times gravity or a continuous unit capable of exerting a minimum force of 3000 times gravity. 5.2. Centrifuge TubesA supply of 250- to 500-mL (8.5- to 16.9-oz) wide-mouth bottles, or centrifuge tubes as shown in Figure 1. 2

14、015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2c R 59-3 AASHTO Metric Equivalents mm in. 0.13 0.005 0.89 0.035 3.18 0.125 27.4 1.080 29.8 1.175 32.9 1.294 64.0 2.520 65.8 2.590 193.0 7.600 Figure 1Ce

15、ntrifuge Tube Source: Department of Civil and Environmental Engineering, Mississippi State University 5.3. Distillation AssemblyAs shown in Figure 2 and consisting of the following items: 5.3.1. Extraction FlasksA 250- to 500-mL (8.5- to 16.9-oz) wide-mouth, heat-resistant flask for distillation and

16、 a suitable flask for the receiver. 5.3.2. Glass TubingHeat-resistant glass tubing, having a 10-mm (0.4-in.) inside diameter and a gooseneck-shaped delivery tube (as shown in Figure 2) for connecting the flask to the condenser. 5.3.3. Inlet Aeration TubeAt least 180 mm (7 in.) in length, having a 6-

17、mm (0.25-in.) outside diameter with a 10-mm (0.4-in.) bulb containing six staggered holes approximately 1.5 mm (0.06 in.) in diameter.2 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2c R 59-4 AASHTO

18、 5.3.4. Electric Heating MantleWith a variable transformer, oil bath, or fluidized sand bath, to fit a 250- to 500-mL (8.5- to 16.9-oz) flask. 5.3.5. Water-Jacketed CondenserAllihn type, with a 200-mm (7.9-in.) minimum jacket length, or equivalent. 5.3.6. ThermometerAn ASTM Low Distillation Thermome

19、ter 7C (7F), having a range of 2 to 300C (28 to 572F), and conforming to the requirements in ASTM E1. 5.3.7. Gas FlowmeterAs shown in Figure 2, or any type capable of indicating a gas flow of up to 1000 mL/min.35.3.8. CorksNo. 20, drilled as shown in Figure 2. 5.3.9. Flexible Elastometric TubingResi

20、stant to chlorinated solvents, having a sufficient length and size to connect the aeration tube to a flowmeter, and may be equipped with a pinch clamp or stopcock to close the aeration tube prior to introducing carbon dioxide. 5.3.10. Separatory Funnel(Alternative procedure, see Section 9.3.1), 125-

21、mL (4.2-oz) capacity or larger.4 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-2c R 59-5 AASHTO Metric Equivalents mm in. 6 0.25 10 0.39 12 0.47 35 1.38 180 7.1 475 18.7 500 19.7 Figure 2Distillatio

22、n Assembly for Asphalt Recovery 6. REAGENTS AND MATERIALS 6.1. Carbon Dioxide GasA pressurized tank, with a pressure-reducing valve, or other convenient source. 6.2. The solvent for extracting the asphalt binder from the mixture should be reagent-grade trichloroethylene or reagent-grade methylene ch

23、loride. Other solvents may affect the recovered asphalt binder and change its properties significantly from those existing in the asphalt mixture (Note 1). 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law

24、.TS-2c R 59-6 AASHTO 7. PRECAUTIONS 7.1. CautionThe solvents listed in Section 6.2 should be used only under a hood, or with an effective surface exhaust system in a well-ventilated area, because they are toxic to some degree as indicated in R 16. 8. SAMPLE 8.1. The sample shall consist of a solutio

25、n, from previous extraction by Method A or E (Note 2) of T 164, of an asphalt mixture sample of sufficient mass to result in about 75 to 100 g of recovered asphalt binder. More or less quantities of asphalt binder may be recovered; however, the properties of the recovered asphalt binder may not be i

26、n agreement with those recovered from a sample of sufficient mass to result in an asphalt binder quantity of 75 to 100 g. In case of a dispute, 75 to 100 g should be recovered. 8.2. During the extraction process, it is important that all of the asphalt binder in the mixture be extracted as there cou

27、ld be some selective solvency of the asphalt binder. The harder, more viscous components of the asphalt binder might be left in the mixture if the extraction is not carried to completion. 8.3. Because heavy petroleum distillates such as mineral spirits or kerosene will affect the properties of the r

28、ecovered asphalt binder, it is important to avoid the use of such solvents in cleaning the extraction and recovery apparatus and to use only trichloroethylene or methylene chloride for cleaning. Residues of heavy petroleum solvents on the equipment may contaminate the recovered asphalt binder and af

29、fect its test properties. It is also necessary to use new filter rings, clean felt pads, or other uncontaminated filtering media in the extraction process to avoid contamination from a previous extraction. 8.4. Generally, the asphalt binder in mixtures will progressively harden when exposed to air,

30、particularly if the mixtures are in a loose condition. Therefore, it is important to protect asphalt mixtures from exposure to air and preferably to store them in airtight containers at a temperature below 0C (32F) until they can be tested. When samples of asphalt mixture are warmed for preparing re

31、presentative portions for extraction tests in accordance with Method A or E (Note 2) of T 164, they should be placed in an oven in covered containers and heated to a maximum temperature of 110C (230F) for the minimum time necessary to achieve workability, but no longer than 30 min. If the samples ha

32、ve been stored at a low temperature, they should be allowed to reach room temperature before placing them in the oven. 9. PROCEDURE 9.1. The entire procedure, from the start of the extraction to the final recovery, must be completed within 8 h. 9.2. Centrifuge the solution from the previous extracti

33、on for a minimum of 30 min at 770 times gravity in 250- to 500-mL (8.5- to 16.9-oz) wide-mouth bottles or centrifuge tubes, as appropriate. If a continuous centrifuge is used, the extract solution shall be charged at a rate not to exceed 150 mL/min (5.1 oz/min), while the unit is operating at a spee

34、d calculated to produce a centrifugal force of not less than 3000 times gravity. 9.3. Concentrate the solution to a volume between 200 and 300 mL (6.8 and 10.1 oz) by any primary distillation operation using a flask large enough to hold all the solution from the extraction. Transfer the residue from

35、 the primary distillation flask, using several washes of solvent to rinse all of the residue into the 250- to 500-mL (8.5- to 16.9-oz) distillation flask. Assemble the apparatus 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a viola

36、tion of applicable law.TS-2c R 59-7 AASHTO as shown in Figure 2, and introduce carbon dioxide gas at a low rate (approximately 100 mL/min) to provide agitation and prevent foaming. Continue the distillation until the temperature reaches 157 to 160C (315 to 320F); at that point, increase the carbon d

37、ioxide gas flow to approximately 900 mL/min. Maintain this gas flow rate for 10 min while also maintaining the temperature of the residue in the flask at 160 to 166C (320 to 330F). The setting of the variable transformer for obtaining this temperature can be established by a few trial runs; generall

38、y, a higher setting can be used for the main distillation. Reduce the setting when most of the solvent has been vaporized. An oil bath or fluidized sand bath may be substituted in place of the electric heating mantle. The temperature of the mantle or bath during the introduction of the carbon dioxid

39、e gas shall be maintained 8 to 14C (15 to 25F) higher than the residue temperature inside the flask. If, after 10 min, dripping of condensed solvent from the delivery tube is still occurring, maintain the gas flow and temperature until 5 min after the dripping ceases in order to flush solvent vapors

40、 from the flask. In no case shall the time of flow of carbon dioxide gas be less than 15 min. At the end of this period, discontinue the gas flow and heat. 9.3.1. Alternative ProcedureAssemble the apparatus as shown in Figure 2 with a separatory funnel in the thermometer hole in the cork. As an alte

41、rnative, the separatory funnel may be inserted in a separate hole drilled in the cork stopper. Raise the aeration tube so that the bulb is above the surface of the solution. Fill the separatory funnel with the centrifuged solution, and open the stopcock to fill the flask approximately one-half full

42、of solution. Apply low heat to the flask, and start distillation. At this time, lower the aeration tube so that the bulb is in contact with the bottom of the flask, and introduce carbon dioxide gas at a low rate (approximately 100 mL/min) to provide agitation and prevent foaming. Adjust the funnel s

43、topcock to introduce fresh solvent at a rate that will keep the flask approximately one-half full during distillation, adding solution to the funnel until all of the solution has been introduced into the distillation flask. Wash the solution container and funnel with fresh solvent to transfer all of

44、 the remaining asphalt binder into the distillation flask. If the separatory funnel has not been inserted into a separate hole drilled in the cork stopper, remove the separatory funnel, and insert the thermometer. When the temperature reaches 157 to 160C (315 to 320F), increase the flow of carbon di

45、oxide gas to approximately 900 mL/min. Maintain this gas flow rate for 10 min while also maintaining the temperature of the residue in the flask at 160 to 166C (320 to 330F). If, after 10 min, dripping of condensed solvent from the delivery tube is still occurring, maintain the gas flow and temperat

46、ure until 5 min after the dripping ceases in order to flush solvent vapors from the flask. In no case shall the time of flow of carbon dioxide gas be less than 15 min. At the end of this period, discontinue the gas flow and heat. 9.4. If the residue in the flask is highly viscous at 163C (325F), so

47、that dispersion of the carbon dioxide in the residue is restricted and the recovered asphalt binder is expected to have a penetration at 25C (77F) of less than 30, maintain the flow of carbon dioxide gas and temperature for 20 to 22 min, which includes the initial 15 min. 9.5. The recovered asphalt

48、binder can be heated to reliquefy it, and portions taken from it for testing. Testing may include dynamic shear, bending beam, direct tension, rotational viscosity, penetration, softening point, ductility, ash content, and kinematic and absolute viscosity determinations, as required. Ash content det

49、erminations shall be conducted on all recovered asphalt binder in accordance with T 111 and reported with other test data on the recovered asphalt binder. Ash contents of recovered asphalt binder greater than 1 percent may affect the accuracy of the penetration, ductility, softening point, or viscosity tests on that material. Note 3Determination of the mass of recovered asphalt binder serves as a check to assure that all of the solvent has been removed when this mass is compared with the mass of extracted asphalt b