ASTM D1856-21

Standard Test Method for Recovery of Asphalt from Solution by Abson Method

SIGNIFICANCE AND USE
4.1 The asphalt should be extracted from the aggregate-asphalt mixture in accordance with Method A of Test Methods D2172/D2172M (centrifuge method) or D8159 as there is some experimental evidence that the recovered asphalt may have slightly lower penetration values when recovered from solutions obtained from hot extraction methods.
SCOPE
1.1 This test method covers the recovery by the Abson method of asphalt from a solution from a previously conducted extraction. The asphalt is recovered with properties substantially the same as those it possessed in the bituminous mixture and in quantities sufficient for further testing.  
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Apr-2021
• ICS: 91.100.50 - Binders. Sealing materials
• ICS: 93.080.20 - Road construction materials
• Technical Committee: D04 - Road and Paving Materials
• Drafting Committee: D04.25 - Analysis of Asphalt Mixtures

Relations

• Refers: ASTM C670-24a - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Feb-2024
• Refers: ASTM C670-24 - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Jan-2024
• Refers: ASTM D4080-15(2020) - Standard Specification for Trichloroethylene, Technical and Vapor-Degreasing Grade
• Effective Date: 01-Jan-2020
• Refers: ASTM D8159-19 - Standard Test Method for Automated Extraction of Asphalt Binder from Asphalt Mixtures
• Effective Date: 01-Jul-2019
• Refers: ASTM D8159-18 - Standard Test Method for Automated Extraction of Asphalt Binder from Asphalt Mixtures
• Effective Date: 01-Jul-2018
• Refers: ASTM D2172/D2172M-17e1 - Standard Test Methods for Quantitative Extraction of Asphalt Binder from Asphalt Mixtures
• Effective Date: 01-Apr-2017
• Refers: ASTM D2172/D2172M-17 - Standard Test Methods for Quantitative Extraction of Asphalt Binder from Asphalt Mixtures
• Effective Date: 01-Apr-2017
• Refers: ASTM D4080-15 - Standard Specification for Trichloroethylene, Technical and Vapor-Degreasing Grade
• Effective Date: 01-Jun-2015
• Refers: ASTM C670-13 - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Jul-2013
• Refers: ASTM E1-13 - Standard Specification for ASTM Liquid-in-Glass Thermometers
• Effective Date: 01-May-2013
• Refers: ASTM D6368-06(2012) - Standard Specification for Vapor-Degreasing Solvents Based on <emph type="bdit">normal</emph>-Propyl Bromide and Technical Grade <emph type="bdit">normal</emph>-Propyl Bromide
• Effective Date: 01-Mar-2012
• Refers: ASTM D4080-00(2011) - Standard Specification for Trichloroethylene, Technical and Vapor-Degreasing Grade
• Effective Date: 01-Aug-2011
• Refers: ASTM D2172/D2172M-11 - Standard Test Methods for Quantitative Extraction of Bitumen From Bituminous Paving Mixtures
• Effective Date: 01-Feb-2011
• Refers: ASTM C670-10 - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Oct-2010
• Refers: ASTM E1-07 - Standard Specification for ASTM Liquid-in-Glass Thermometers
• Effective Date: 01-Nov-2007

Overview

ASTM D1856-21: Standard Test Method for Recovery of Asphalt from Solution by Abson Method sets out the procedures for recovering asphalt from previously extracted asphalt solutions. Developed by ASTM International, this standard ensures that the recovered asphalt retains properties substantially similar to those originally present in the bituminous mixture, enabling further physical and chemical analysis. The Abson method is recognized for its reliability in preparing asphalt samples for subsequent testing, assisting in quality control and research for pavement materials.

The test method applies specifically following extractions performed in accordance with ASTM D2172/D2172M (centrifuge method) or D8159. This standard emphasizes the significance of using approved extraction techniques, as recovery from solutions derived from hot extraction methods may yield asphalt with slightly altered penetration values.

Key Topics

• Scope and Purpose: The standard provides a detailed method for the recovery of asphalt binder from solution using the Abson method, maintaining the integrity of the sample for further testing.
• Apparatus and Materials: Specifies the necessary equipment, including centrifuges, distillation assemblies, carbon dioxide supply, and temperature regulation devices.
• Safety Considerations: Calls attention to the toxic nature of extraction solvents such as trichloroethylene and normal propyl bromides and emphasizes the requirement for effective ventilation and safe handling practices.
• Sample Preparation: Details the importance of complete extraction and protection of bituminous mixtures from airborne hardening and contamination.
• Recovery Procedure: Outlines the distillation process, with precise temperature and carbon dioxide flow controls, ensuring effective removal of solvents and accurate recovery of the binder.
• Precision and Bias: Discusses the repeatability and reproducibility of the test results as observed in single- and multilaboratory scenarios.
• Regulatory Compliance: Encourages adherence to national and international safety and environmental guidelines during test execution.

Applications

The Abson recovery method under ASTM D1856-21 is a critical procedure in:

• Asphalt Mixture Analysis: Recovered asphalt can be subjected to essential tests for penetration, viscosity, ductility, softening point, and ash content, supporting both quality control and forensic analysis of pavement failures.
• Materials Research: Researchers and paving technologists utilize this standard to assess the effects of aging, recycling, or environmental exposure on asphalt binder from roadways.
• Regulatory Compliance and Specification Checking: Departments of transportation, construction quality assurance labs, and paving contractors use this method to verify asphalt binder compliance with contract specifications and national standards.
• Recycling and Reuse: Recovery and testing of asphalt binders from reclaimed asphalt pavement (RAP) facilitate the evaluation and optimization of recycling practices in sustainable road construction.

Related Standards

Several ASTM standards are referenced or used in conjunction with ASTM D1856-21 to support asphalt extraction and recovery processes:

• ASTM D2172/D2172M: Test Methods for Quantitative Extraction of Asphalt Binder from Asphalt Mixtures
• ASTM D8159: Test Method for Automated Extraction of Asphalt Binder from Asphalt Mixtures
• ASTM D4080: Specification for Trichloroethylene, Technical and Vapor-Degreasing Grade
• ASTM D6368: Specification for Vapor-Degreasing Solvents Based on normal-Propyl Bromide and Technical Grade normal-Propyl Bromide
• ASTM C670: Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• ASTM E1: Specification for ASTM Liquid-in-Glass Thermometers

These related standards ensure a comprehensive approach to asphalt mixture analysis, extraction, recovery, and testing, supporting consistent and reliable results across diverse laboratories and applications.

Keywords: ASTM D1856-21, Abson method, asphalt recovery, bituminous mixture, solvent distillation, reclaimed asphalt, penetration tests, asphalt binder analysis, material quality control, road construction standards.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D1856 − 21
Standard Test Method for
Recovery of Asphalt from Solution by Abson Method
This standard is issued under the fixed designation D1856; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D6368Specification for Vapor-Degreasing Solvents Based
on normal-Propyl Bromide and Technical Grade normal-
1.1 This test method covers the recovery by the Abson
Propyl Bromide
methodofasphaltfromasolutionfromapreviouslyconducted
D8159Test Method for Automated Extraction of Asphalt
extraction. The asphalt is recovered with properties substan-
Binder from Asphalt Mixtures
tially the same as those it possessed in the bituminous mixture
E1Specification for ASTM Liquid-in-Glass Thermometers
and in quantities sufficient for further testing.
1.2 The values stated in SI units are to be regarded as the
3. Summary of Test Method
standard. The values given in parentheses are provided for
information only.
3.1 The solution of solvent and asphalt from an asphalt mix
extraction is distilled under prescribed conditions to a point
1.3 This standard does not purport to address all of the
where most of the solvent has been distilled, at which time
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- carbon dioxide gas is introduced into the distillation process to
priate safety, health, and environmental practices and deter- remove all traces of the extraction solvent. The recovered
mine the applicability of regulatory limitations prior to use. asphalt (distillation residue) can then be subjected to further
1.4 This international standard was developed in accor- testing as required.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4. Significance and Use
Development of International Standards, Guides and Recom-
4.1 The asphalt should be extracted from the aggregate-
mendations issued by the World Trade Organization Technical
asphalt mixture in accordance with MethodAof Test Methods
Barriers to Trade (TBT) Committee.
D2172/D2172M (centrifuge method) or D8159 as there is
some experimental evidence that the recovered asphalt may
2. Referenced Documents
have slightly lower penetration values when recovered from
2.1 ASTM Standards:
solutions obtained from hot extraction methods.
C670Practice for Preparing Precision and Bias Statements
for Test Methods for Construction Materials
5. Apparatus
D2172/D2172MTestMethodsforQuantitativeExtractionof
Asphalt Binder from Asphalt Mixtures
5.1 Centrifuge, batch unit capable of exerting a minimum
D2939Test Methods for Emulsified Bitumens Used as
centrifugal force of 770 times gravity or continuous unit
Protective Coatings (Withdrawn 2012)
capable of exerting a minimum force of 3000 times gravity.
D4080Specification for Trichloroethylene, Technical and
5.2 Centrifuge Tubes—A supply of wide-mouth bottles or
Vapor-Degreasing Grade
centrifuge tubes may be used for the batch unit. A tube as
illustrated in Fig. 1 has been found satisfactory for the
continuous unit.
This test method is under the jurisdiction of ASTM Committee D04 on Road
and Paving Materials and is the direct responsibility of Subcommittee D04.25 on
5.3 DistillationAssembly,asshowninFig.2,andconsisting
Analysis of Asphalt Mixtures.
of the following items:
Current edition approved May 1, 2021. Published June 2021. Originally
approved in 1961. Last previous edition approved in 2015 as D1856–09 (2015).
5.3.1 Extraction Flasks—Two 250-mL, wide-mouth, heat-
DOI: 10.1520/D1856-21.
resistant flasks, one for distillation and the other for the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
receiver.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
5.3.2 Glass Tubing—Heat-resistant glass tubing, having
the ASTM website.
3 10-mm inside diameter and gooseneck shaped (as shown in
The last approved version of this historical standard is referenced on
www.astm.org. Fig. 2) for connecting the flask to the condenser.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1856 − 21
FIG. 1 Centrifuge Tube Example
FIG. 2 Distillation Assembly for Bitumen Recovery
D1856 − 21
5.3.3 InletAerationTube, atleast180mminlength,having well-ventilated area, since they are toxic to various degrees.
a 6-mm outside diameter with a 10-mm bulb carrying six Consult the currentThreshold Limit Concentration Committee
staggered side holes approximately 1.5 mm in diameter. of the American Conference of Governmental Industrial Hy-
5.3.4 ElectricHeatingMantle,withvariabletransformer,oil gienists for the current threshold limit values.
bath, or fluidized sand bath, to fit a 250-mL flask.
7.2 Thesesolventsinthepresenceofheatandmoisturemay
5.3.5 Water-Jacketed Condenser, Allihn type, with 200-mm
be hydrolyzed to form acids that are extremely corrosive to
minimum jacket length or equivalent.
certain metals, particularly when subjected to contact over
5.3.6 Thermometer—AnASTMLowDistillationThermom-
lengthy periods of time. Proper precautions should be taken to
eter 7E or 7F, as specified, having a range from−2 to 300°C
not allow these solvents to remain in small quantities in the
or 30 to 580°F, respectively, and conforming to the require-
effluent tanks of aluminum vacuum extractors.
ments in Specification E1.
7.3 Exposure of these solvents or their vapors to high
5.3.7 Gas Flowmeter, as shown in Fig. 2, or any flowmeter
temperaturessuchascontactwithflames,hotglowingsurfaces,
capable of indicating a gas flow of up to 1000 mL/min.
or electric arcs can produce decomposition products such as
5.3.8 Corks, No. 20, drilled as shown in Fig. 2.
hydrogen chloride. Steel drums containing these solvents
5.3.9 Flexible Elastomeric Tubing, resistant to chlorinated
shouldbestoredinacool,drylocation,kepttightlysealed,and
solvents having sufficient length and size to connect the
opened as infrequently as possible. The hydrogen chloride in
aerationtubetoflowmeter,andequippedwithapinchclampor
decomposed solvent may harden an asphalt during the extrac-
stopcock to close aeration tube prior to introducing carbon
tion and recovery test.
dioxide.
5.3.10 Separatory Funnel, (alternative procedure; see
8. Sample
9.3.1) 125-mL capacity.
8.1 Thesampleshallconsistofthesolutionfromaprevious
6. Reagents and Materials
extraction by Method A of Test Methods D2172/D2172M or
D8159 of asphalt-aggregate mixture of sufficient quantity to
6.1 Carbon Dioxide Gas—A pressurized tank, with
result in 75 to 100 g of recovered bitumen. More or less
pressure-reducing valve or other convenient source.
quantities of bitumen may be recovered; however, the proper-
6.2 Solvents:
ties of the recovered bitumen may not be in agreement with
6.2.1 The solvent for extracting the asphalt from mixtures
those recovered of the aforementioned quantities, and in case
may be trichloroethylene, conforming with Specification
of a disagreement, 75 to 100 g should be recovered.
D4080.
8.2 During the extraction process, it is important that all of
6.2.2 The solvent for extracting the asphalt from mixtures
the asphalt in the mixture be extracted as there could be some
may be normal propyl bromides (nPB). This solvent should
selective solvency of the asphalt and the harder, more viscous
conform to Specification D6368.
components of the asphalt might be left in the mixture if
6.2.3 The solvent for extracting the asphalt from mixtures
extraction is not carried to completion.
may be reagent grade methylene chloride.
8.3 Since heavy petroleum distillates such as mineral spirits
7. Precautions
or kerosine will affect the properties of the recovered asphalt,
7.1 Warning—Thesolventlistedin6.2shouldbeusedonly it is important to avoid the use of such solvents in cleaning the
under a hood or with an effective surface exhaust system in a
extraction and recovery apparatus and use only trichloroethyl-
ene for cleaning. Residues of heavy petroleum solvents on the
equipmentmaycontaminatetherecoveredasphaltandaffectits
The sole source of supply of the apparatus known to the committee at this time
testproperties.Itisalsonecessarytousenewfilterrings,clean
is Inlet Aeration Tube, Part No. 226, available from Wm. A. Sales, Ltd., 419
Harvester Court, Wheeling, Ill. 60090; request Part No. 226. If you are aware of felt pads, or other uncontaminated filtering media in the
alternative suppliers, please provide this information to ASTM International
extraction process to avoid contamination from a previous
Headquarters.Your comments will receive careful consideration at a meeting of the
1 extraction.
responsible technical committee, which you may attend.
The sole source of supply of the apparatus known to the committee at this time
8.4 Generally, the bitumen in mixtures will progressively
is The Monostat Corp. “Flowmeter” No. 9144. If you are aware of alternative
harden when exposed to air, particularly if the mixtures are in
suppliers, please provide this information to ASTM International Headquarters.
Your comments will receive careful consideration at a meeting of the responsible a loose condition. Therefore, it is important to protect bitumi-
technical committee, which you may attend.
nous mixtures from exposure to air and preferably to store
The sole source of supply of the apparatus known to the committee at this time
them in airtight containers at a temperature below 0°C (32°F)
is Kimball separatory funnel No. 29028. If y
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D1856 − 09 (Reapproved 2015) D1856 − 21
Standard Test Method for
Recovery of Asphalt Fromfrom Solution by Abson Method
This standard is issued under the fixed designation D1856; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the recovery by the Abson method of asphalt from a solution from a previously conducted extraction.
The asphalt is recovered with properties substantially the same as those it possessed in the bituminous mixture and in quantities
sufficient for further testing.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information
only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
D2172D2172/D2172M Test Methods for Quantitative Extraction of Asphalt Binder from Asphalt Mixtures
D2939 Test Methods for Emulsified Bitumens Used as Protective Coatings (Withdrawn 2012)
D4080 Specification for Trichloroethylene, Technical and Vapor-Degreasing Grade
D6368 Specification for Vapor-Degreasing Solvents Based on normal-Propyl Bromide and Technical Grade normal-Propyl
Bromide
D8159 Test Method for Automated Extraction of Asphalt Binder from Asphalt Mixtures
E1 Specification for ASTM Liquid-in-Glass Thermometers
3. Summary of Test Method
3.1 The solution of solvent and asphalt from an asphalt mix 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 solvent. The recovered asphalt (distillation residue) can then be subjected to further testing as required.
This test method is under the jurisdiction of ASTM Committee D04 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.25 on Analysis
of Asphalt Mixtures.
Current edition approved Jan. 1, 2015May 1, 2021. Published February 2015June 2021. Originally approved in 1961. Last previous edition approved in 20092015 as
D1856 – 09.D1856 – 09 (2015). DOI: 10.1520/D1856-09R15.10.1520/D1856-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1856 − 21
4. Significance and Use
4.1 The asphalt should be extracted from the aggregate-asphalt mixture in accordance with Method A of Test Methods
D2172D2172/D2172M (centrifuge method) or D8159 as there is some experimental evidence that the recovered asphalt may have
slightly lower penetration values when recovered from solutions obtained from hot extraction methods.
5. Apparatus
5.1 Centrifuge, batch unit capable of exerting a minimum centrifugal force of 770 times gravity or continuous unit capable of
exerting a minimum force of 3000 times gravity.
5.2 Centrifuge Tubes—A supply of wide-mouth bottles or centrifuge tubes may be used for the batch unit. A tube as illustrated
in Fig. 1 has been found satisfactory for the continuous unit.
5.3 Distillation Assembly, as shown in Fig. 2, and consisting of the following items:
5.3.1 Extraction Flasks—Two 250-ml,250-mL, wide-mouth, heat-resistant flasks, one for distillation and the other for the receiver.
5.3.2 Glass Tubing—Heat-resistant glass tubing, having 10-mm inside diameter and gooseneck shaped (as shown in Fig. 2) for
connecting the flask to the condenser.
5.3.3 Inlet Aeration Tube, at least 180 mm in length, having a 6-mm outside diameter with a 10-mm bulb carrying six staggered
side holes approximately 1.5 mm in diameter.
FIG. 1 Centrifuge Tube Example
The sole source of supply of the apparatus known to the committee at this time is Inlet Aeration Tube, Part No. 226, available from Wm. A. Sales, Ltd., 419 Harvester
Court, Wheeling, Ill. 60090; request Part No. 226. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your
comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.
D1856 − 21
FIG. 2 Distillation Assembly for Bitumen Recovery
5.3.4 Electric Heating Mantle, with variable transformer, oil bath, or fluidized sand bath, to fit a 250-ml250-mL flask.
5.3.5 Water-Jacketed Condenser, Allihn type, with 200-mm minimum jacket length or equivalent.
5.3.6 Thermometer—An ASTM Low Distillation Thermometer 7E or 7F, as specified, having a range from −2 to 300°C300 °C or
30 to 580°F,580 °F, respectively, and conforming to the requirements in Specification E1.
5.3.7 Gas Flowmeter, as shown in Fig. 2, or any flowmeter capable of indicating a gas flow of up to 1000 ml/min.mL/min.
5.3.8 Corks, No. 20, drilled as shown in Fig. 2.
5.3.9 Flexible Elastomeric Tubing, resistant to chlorinated solvents having sufficient length and size to connect the aeration tube
to flowmeter, and equipped with a pinch clamp or stopcock to close aeration tube prior to introducing carbon dioxide.
5.3.10 Separatory Funnel, ((alternativeAlternative Procedure, procedure; see 9.3.1) 125-ml125-mL capacity.
6. Reagents and Materials
6.1 Carbon Dioxide Gas—A pressurized tank, with pressure-reducing valve or other convenient source.
6.2 Solvents:
6.2.1 The solvent for extracting the asphalt from mixtures may be trichloroethylene, conforming with Specification D4080.
The sole source of supply of the apparatus known to the committee at this time is The Monostat Corp. “Flowmeter” No. 9144. If you are aware of alternative suppliers,
please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee,
which you may attend.
The sole source of supply of the apparatus known to the committee at this time is Kimball separatory funnel No. 29028. If you are aware of alternative suppliers, please
provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which
you may attend.
The sole source of supply of the apparatus known to the committee at this time is American Conference of Governmental Industrial Hygienists, Inc. (ACGIH), 1330
Kemper Meadow Dr., Cincinnati, OH 45240, (http://www.acgih.org). If you are aware of alternative suppliers, please provide this information to ASTM International
Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.
D1856 − 21
6.2.2 The solvent for extracting the asphalt from mixtures may be Normal Propyl Bromidesnormal propyl bromides (nPB). This
solvent should conform to Specification D6368.
6.2.3 The solvent for extracting the asphalt from mixtures may be reagent grade Methylene Chloride.methylene chloride.
7. Precautions
7.1 Warning—The solvent listed in 6.2 should be used only under a hood or with an effective surface exhaust system in a
well-ventilated area, since they are toxic to various degrees. Consult the current Threshold Limit Concentration Committee of the
American Conference of Governmental Industrial Hygienists for the current threshold limit values.Warning—The solvent listed
in 6.2 should be used only under a hood or with an effective surface exhaust system in a well-ventilated area, since they are toxic
to various degrees. Consult the current Threshold Limit Concentration Committee of the American Conference of Governmental
Industrial Hygienists for the current threshold limit values.
7.2 These solvents in the presence of heat and moisture may be hydrolyzed to form acids that are extremely corrosive to certain
metals, particularly when subjectsubjected to contact over lengthy periods of time. Proper precautions should be taken to not allow
these solvents to remain in small quantities in the effluent tanks of aluminum vacuum extractors.
7.3 Exposure of these solvents or their vapors to high temperatures such as contact with flames, hot glowing surfaces, or electric
arcs can produce decomposition products such as hydrogen chloride. Steel drums containing these solvents should be stored in a
cool, dry location, kept tightly sealed, and opened as infrequently as possible. The hydrogen chloride in decomposed solvent may
harden an asphalt during the extraction and recovery test.
8. Sample
8.1 The sample shall consist of the solution from a previous extraction by Method A of Test Methods D2172D2172/D2172M or
D8159 of asphalt-aggregate mixture of sufficient quantity to result in 75 to 100 g of recovered bitumen. More or less quantities
of bitumen may be recovered; however, the properties of the recovered bitumen may not be in agreement with those recovered of
the aforementioned quantities, and in case of a disagreement, 75 to 100 g should be recovered.
8.2 During the extraction process, it is important that all of the asphalt in the mixture be extracted as there could be some selective
solvency of the asphalt and the harder, more viscous components of the asphalt might be left in the mixture if extraction is not
carried to completion.
8.3 Since heavy petroleum distillates such as mineral spirits or kerosine will affect the properties of the recovered asphalt, it is
important to avoid the use of such solvents in cleaning the extra
...