ASTM D2171/D2171M-22

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: D2171/D2171M − 18 D2171/D2171M − 22
Standard Test Method for
Viscosity of Asphalts by Vacuum Capillary Viscometer
This standard is issued under the fixed designation D2171/D2171M; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
This test method has been approved by the sponsoring committees and accepted by the cooperating societies in accordance with
established procedures.
1. Scope
1.1 This test method covers procedures for the determination of the apparent viscosity of asphalt binder by vacuum capillary
viscometers at 60 °C [140 °F]. It is applicable to materials having viscosities in the range from 0.0036 to over 20 000 Pa·s [0.036
to over 200 000 P].
NOTE 1—This test method is suitable for use at other temperatures, but the precision is based on determinations on asphalt binders at 60 °C [140 °F].
NOTE 2—Modified asphalt binders or asphalt binders that have been conditioned or recovered are typically non-Newtonian under the conditions of this
test. The apparent viscosity for non-Newtonian asphalt binders varies with shear rate. When the flow is non-Newtonian in a capillary tube, the shear rate
determined using this test method may be invalid. The presence of non-Newtonian behavior for the test conditions of this test can be verified by measuring
the viscosity with viscometers having different-sized capillary tubes or with different pressure heads. The defined precision limits in Section 11 may not
be applicable to non-Newtonian asphalt binders. Test Method D4957 may be a more applicable method for testing non-Newtonian asphalts.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in nonconformance with the standard.
1.3 Warning—Mercury has been designated by the United States Environmental Protection Agency (EPA) and many state
agencies as a hazardous material that can cause central nervous system, kidney, and liver damage. Mercury, or its vapor, may be
hazardous to health and corrosive to materials. Caution should be taken when handling mercury and mercury-containing products.
See the applicable product Material Safety Data Sheet (MSDS) or Safety Data Sheet (SDS) for details and the EPA’s
website—http://www.epa.gov/mercury/faq.htm—for additional information. Users should be aware that selling mercury, mercury-
containing products, or both, in your state may be prohibited by state law.
1.4 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered as requirements of the standard.
1.5 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.
1.6 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.
This test method is under the jurisdiction of ASTM Committee D04 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.44 on Rheological
Tests.
Current edition approved Dec. 15, 2018Nov. 1, 2022. Published December 2018November 2022. Originally approved in 1963. Last previous edition approved in 20102018
as D2171/D2171M – 10.D2171/D2171M – 18. DOI: 10.1520/D2171_D2171M-18.10.1520/D2171_D2171M-22.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2171/D2171M − 22
2. Referenced Documents
2.1 ASTM Standards:
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
D8 Terminology Relating to Materials for Roads and Pavements
D3666 Specification for Minimum Requirements for Agencies Testing and Inspecting Road and Paving Materials
D4957 Test Method for Apparent Viscosity of Asphalt Emulsion Residues and Non-Newtonian Asphalts by Vacuum Capillary
Viscometer
E1 Specification for ASTM Liquid-in-Glass Thermometers
E11 Specification for Woven Wire Test Sieve Cloth and Test Sieves
E77 Test Method for Inspection and Verification of Thermometers
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E879 Specification for Thermistor Sensors for General Purpose and Laboratory Temperature Measurements
E1137/E1137M Specification for Industrial Platinum Resistance Thermometers
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 Newtonian viscosity, n—the viscosity of a liquid that is shear-rate independent, in which the rate of shear is linearly
proportional to the shearing stress.
3.1.2 non-Newtonian viscosity, n—the viscosity of a liquid that is shear-rate dependent, in which the rate of shear is not linearly
proportional to the shearing stress.
3.1.3 viscosity (coeffıcient of), n—the ratio between the applied shear stress and rate of shear is called the coefficient of viscosity.
3.1.3.1 Discussion—
This coefficient is a measure of the resistance to flow of the liquid. It is commonly called the viscosity of the liquid. The cgs unit
2 2
of viscosity is 1 g/cm·s (1 dyne·s ⁄cm ) and is called a poise (P). The SI unit of viscosity is 1 Pa·s (1 N·s/m ) and is called a
Pascal-second. One Pa·s is equivalent to 10 P.
3.2 For definitions of other terms used in this standard, refer to Terminology D8.
4. Summary of Test Method
4.1 The time is measured for a fixed volume of the liquid to be drawn up through a capillary tube by means of vacuum, under
closely controlled conditions of vacuum and temperature. The viscosity in Pascal-seconds is calculated by multiplying the flow
time in seconds by the viscometer calibration factor.
5. Significance and Use
5.1 The viscosity at 60 °C [140 °F] characterizes flow behavior and may be used for specification requirements for cutback asphalt
and asphalt binders.
NOTE 3—The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the
capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of Specification D3666 are generally considered capable
of competent and objective testing, sampling, inspection, etc. Users of this standard are cautioned that compliance with Specification D3666 alone does
not completely ensure reliable results. Reliable results depend on many factors; following the suggestions of Specification D3666 or some similar
acceptable guideline provides a means of evaluating and controlling some of those factors.
6. Apparatus
6.1 Viscometers, capillary-type, made of borosilicate glass, annealed, suitable for this test are as follows:
6.1.1 Cannon-Manning Vacuum Viscometer (CMVV), as described in Appendix X1.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
D2171/D2171M − 22
6.1.2 Asphalt Institute Vacuum Viscometer (AIVV), as described in Appendix X2.
6.1.3 Modified Koppers Vacuum Viscometer (MKVV), as described in Appendix X3.
6.1.4 Calibrated viscometers are available from commercial suppliers. Details regarding calibration of viscometers are given in
Appendix X4.
NOTE 4—The viscosity measured in a CMVV may be from 1 to 5 % lower than either the AIVV or MKVV having the same viscosity range. This
difference, when encountered, may be the result of non-Newtonian flow.
6.2 Thermometers—A calibrated thermometer (see Table X5.1) with suitable range and estimated measurement uncertainty of
0.02 °C [0.04 °F] or less at 95 % confidence interval listed on the calibration certificate and is one of the following:
6.2.1 A liquid-in-glass thermometer that is calibrated annually. The calibration shall be verified at the ice point in accordance with
Appendix X5. ASTM Kinematic Viscosity Thermometers 47C and 47F conforming to Specification E1 are suitable for the most
commonly used temperature of 60 °C [140 °F].
NOTE 5—The specified thermometers in 6.2.1 are standardized as “total immersion” thermometers, which are designed to indicate temperatures correctly
when just that portion of the thermometer containing the liquid is exposed to the temperature being measured and the remainder of the stem and expansion
chamber at the top of the thermometer exposed to the room temperature. The practice of completely submerging the thermometer is not recommended.
When a “total immersion” thermometer is completely submerged, corrections for each individual thermometer based on calibration under conditions of
complete submergence must be determined and applied. If the thermometer is completely submerged in the bath during use, the pressure of the gas in
the expansion chamber will be higher or lower than during calibration, and may cause high or low readings on the thermometer.
6.2.2 A platinum resistance thermometer (PRT) with a sensor which conforms to the requirements of Specification E1137/
E1137M. The thermometer shall be calibrated annually as a single unit and have a three- or four-wire connection configuration.
The sensing element shall be immersed to the depth specified by the manufacturer adjacent to the capillary tube.
NOTE 6—A minimum of 50 mm (2 in.)[2 in.] of the thermometer sheath (wire-connecting side) shall not be subjected to the bath medium unless otherwise
specified by the manufacturer.
6.2.3 A thermistor thermometer with sensor, which conforms to the requirements of Specification E879, calibrated annually as a
single unit. The sensing element of the thermistor shall be completely immersed in the bath adjacent to the capillary tube.
NOTE 7—The use of the thermometric devices specified in 6.2.2 and 6.2.3 are understood to introduce bias in the precision in this method.
6.3 Bath—A bath suitable for immersion of the viscometer so that the liquid reservoir or the top of the capillary, whichever is
uppermost, is at least 20 mm below the upper surface of the bath liquid and with provisions for visibility of the viscometer and
the thermometer. Firm supports for the viscometer shall be provided. The efficiency of the stirring and the balance between heat
losses and heat input must be such that the temperature of the bath medium does not vary by more than 60.03 °C [60.05 °F] over
the length of the viscometer, or from viscometer to viscometer in the various bath positions.
6.4 Vacuum System—A vacuum system capable of maintaining a vacuum to within 60.5 mm Hg of the desired level up to and
including 40.0 kPa [300 mm Hg]. The essential system is shown schematically in Fig. 1. Tubing of 6.35-mm6.35 mm [ ⁄4-in.] in.]
inside diameter should be used, and all joints should be airtight so that when the system is closed, no loss of vacuum is indicated
by the pressure gauge. A vacuum or aspirator pump is suitable for the vacuum source. The vacuum measuring system for this test
method must be standardized at least once a year.
6.5 Timer—A stopwatch or other timing device graduated in divisions of 0.1 s or less and accurate to within 0.05 % when tested
over intervals of not less than 15 min. Timing devices for this test method must be standardized at least every twelve months.
6.5.1 Electrical Timing Devices may be used only on electrical circuits, the frequencies of which are controlled to an accuracy of
0.05 % or better.
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D04-1003. Contact ASTM Customer
Service at service@astm.org.
D2171/D2171M − 22
FIG. 1 Suggested Vacuum System for Vacuum Capillary Viscometers
6.5.1.1 Alternating currents, the frequencies of which are intermittently and not continuously controlled, as provided by some
public power systems, can cause large errors, particularly over short timing intervals, when used to actuate electrical timing
devices.
7. Sample Preparations
7.1 Heat the sample with care to prevent local overheating until it has become sufficiently fluid to pour, occasionally stirring the
sample to aid heat transfer and to ensure uniformity.
7.2 Transfer a minimum of 20 mL into a suitable container and heat to 135 6 5.5 °C [275 6 10 °F], stirring occasionally to prevent
local overheating and taking care to avoid the entrapment of air.
NOTE 8—If it is suspected that the sample may contain solid material, strain the melted sample into the container through a 300-μm [No. 50]300 μm (No.
50) sieve conforming to Specification E11.
NOTE 9—In the case of very viscous or modified asphalts, it may be necessary to heat in an oven at 163 6 5 °C [325 6 10 °F] in order for the material
to become sufficiently fluid to stir and pour.
8. Procedure
8.1 The specific details of operation vary somewhat for the various types of viscometers. See the detailed descriptions of
viscometers in Appendix X1 – Appendix X3 for instructions for using the type of viscometer selected. In all cases, however, follow
the general procedure described in 8.1.1 – 8.1.9.
8.1.1 Maintain the bath at the test temperature within 60.03 °C [0.05 °F]. Apply the necessary corrections, if any, to all
thermometer readings.
8.1.2 Select a clean, dry viscometer that will give a flow time greater than 60 s, and preheat to 135 6 5.5 °C [275 6 10 °F].
8.1.3 Charge the viscometer by pouring the prepared sample to within 62 mm of fill line E (Figs. 2-4).
8.1.4 Place the charged viscometer in an oven or bath maintained at 135 6 5.5 °C [275 6 10 °F] for a period of 10 6 2 min, to
allow large air bubbles to escape.
8.1.5 Remove the viscometer from the oven or bath and, within 5 min, insert the viscometer in a holder, and position the
viscometer vertically in the bath so that the uppermost timing mark is at least 20 mm below the surface of the bath liquid.
8.1.6 Establish a 40.0 6 0.07 kPa [300 6 0.5 mm Hg] vacuum below atmospheric pressure in the vacuum system and connect
the vacuum system to the viscometer with the toggle valve or stopcock closed in the line leading to the viscometer.
D2171/D2171M − 22
All dimensions are in millimetres.
FIG. 2 Cannon-Manning Vacuum Capillary Viscometer
All dimensions are in millimetres.
FIG. 3 Asphalt Institute Vacuum Capillary Viscometer
D2171/D2171M − 22
All dimensions are in millimetres.
FIG. 4 Modified Koppers Vacuum Capillary Viscometer
8.1.7 After the viscometer has been in the bath for 30 6 5 min, 5 min, start the flow of asphalt in the viscometer by opening the
toggle valve or stopcock in the line leading to the vacuum system.
8.1.8 Measure to within 0.1 s the time required for the leading edge of the meniscus to pass between successive pairs of timing
marks. Report the first flow time which exceeds 60 s between a pair of timing marks, noting the identification of the pair of timing
marks.
8.1.9 Upon completion of the test, clean the viscometer thoroughly by several rinsings with an appropriate solvent completely
miscible with the sample, followed by a completely volatile solvent. Dry the tube by passing a slow stream of filtered dry air
through the capillary for 2 min, or until the last trace of solvent is removed. Alternatively, the viscometer may be cleaned in a
glass-cleaning oven,oven at a temperature not to exceed 500 °C [932 °F], followed by rinses with distilled or deionized water,
residue-free acetone, and filtered dry air. Periodically, if deposits are observed, clean the instrument with a strong acid cleaning
solution to remove organic deposits, rinse thoroughly with distilled or deionized water and residue-free acetone, and dry with
filtered dry air.
8.1.9.1 Chromic acid cleaning solution may be prepared by adding, with the usual precautions, 800 mL of concentrated sulphuric
acid to a solution of 92 g of sodium dichromate in 458 mL of water. The use of similar commercially available sulphuric acid
cleaning solutions is acceptable. Nonchromium-containing, strongly oxidizing acid cleaning solutions may be substituted so as to
avoid the disposal problems of chromium-containing solutions.
8.1.9.2 Use of alkaline glass-cleaning solutions may result in a change of viscometer calibration, and is not recommended.
9. Calculation
9.1 Select the calibration factor that corresponds to the pair of timing marks used for the determination, as prescribed in 8.1.8.
Calculate and report the viscosity to three significant figures using the following equation:
Viscosity, Pa·s5 Kt (1)
~ !
D2171/D2171M − 22
TABLE 1 Acceptability of Test Results for Vacuum Capillary
Viscosity for Liquid Asphalts at 60 °C
Acceptable
Coefficient of
Range of Two
Material and Type Index Variation
Results
A
(% of mean)
A
(% of mean)
Single-operator precision:
Unconditioned liquid asphalts at 60 °C 2.62 7.41
[140 °F]
Rolling thin-film oven conditioned liquid 2.81 7.95
asphalts at 60 °C [140 °F]
Multilaboratory precision:
Unconditioned liquid asphalts at 60 °C 4.56 12.9
[140 °F]
Rolling thin-film oven conditioned liquid 7.27 20.6
asphalts at 60 °C [140 °F]
A
These numbers represent, respectively, the (1s%) and (d2s%) limits as de-
scribed in Practice C670.
where:
K = selected calibration factor, Pa·s/s, and
t = flow time, s.
where:
K = selected calibration factor, Pa·s/s, and
t = flow time, s.
NOTE 10—If the viscometer constant or calibration factor (K ) is known in cgs units (Poise/s)(Poise/s), calculate the calibration factor (Ksi) in SI units
cgs
(pascal·seconds/second) as follows:
Ksi 5 ~Pa·s/s!5 K /10 or ~P/s!/10 (2)
cgs
10. Report
10.1 Always report the test temperature and vacuum with the viscosity test result.
NOTE 11—For example, viscosity at 60 °C [140 °F] and 40.0 kPa [300 mm Hg] vacuum, in Pa·s.
11. Precision and Bias
11.1 The precision of this test method is based on an interlaboratory study of ASTM D2171/D2171M, Test Method for Viscosity
of Asphalts by Vacuum Capillary Viscometer, conducted in 2015 to 2019. One hundred twenty-four volunteer laboratories were
asked to test nine different materials. Every “test result” represents an individual determination, and al
...