ASTM D4957-95

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D 4957 – 95
Standard Test Method for
Apparent Viscosity of Asphalt Emulsion Residues and Non-
Newtonian Bitumens by Vacuum Capillary Viscometer
This standard is issued under the fixed designation D4957; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope ratio of the shear stress to shear rate, whether this ratio is
constant or not. The unit of viscosity obtained by dividing the
1.1 This test method describes procedures primarily de-
shearing stress in dynes/cm by the rate of shear in reciprocal
signed to determine the apparent viscosities of residues ob-
seconds is called the poise (P). The SI unit of viscosity is the
tained by distilling asphalt emulsions according to Test Meth-
pascal-second(Pa·s)withdimensionsofN·s/m ,andisequiva-
ods D244. It is also recommended for use on non-Newtonian
lent to 10 P.
asphalts at any temperature within the capability of the
3.1.2 Newtonian liquid—a liquid in which the rate of shear
apparatus. This test method is useful in characterizing rheo-
is proportional to the shearing stress. The constant ratio of the
logical properties of non-Newtonian bitumens as a function of
shearing stress to rate of shear is the viscosity of the liquid. If
shear rate under the conditions of the test method. This test is
the ratio is not constant, the liquid is non-Newtonian.
run in straight open-end tube viscometers, normally at 140°F
(60°C), but is suitable for use at other temperatures. It is
NOTE 2—Apower law fluid is a material in which the relation between
applicable over the range from 50 to 500 000 P (5 to 50 000
thelogoftheshearstressislinearwiththelogoftheshearrate.Theslope
of this relation is called the shear susceptibility, C. If C is less than unity,
Pa·s).
the material is classified as pseudoplastic and the apparent viscosity
NOTE 1—The precision for this test method is based on determinations
decreases with increased stress. If C is greater than one, the material is
made at 140°F (60°C).
dilatant and the apparent viscosity increases with stress. If C is unity the
material shows Newtonian flow. Most real materials show some non-
1.2 This standard does not purport to address all of the
Newtonian behavior and the apparent viscosity, computed as stress
safety concerns, if any, associated with its use. It is the
divided by the shear rate, is reported.
responsibility of the user of this standard to establish appro-
3.1.3 rheogram—a rheological diagram which shows how
priate safety and health practices and determine the applica-
the apparent viscosity of a material varies with the shear rate.
bility of regulatory limitations prior to use.
−1
An apparent viscosity at a specific shear rate, normally 1 s
2. Referenced Documents
can be estimated from this plot. A typical rheogram with an
example is shown in Fig. 1.
2.1 ASTM Standards:
D244 Test Methods for Emulsified Asphalts
4. Summary of Test Method
D2171 Test Method for Viscosity of Asphalts by Vacuum
4.1 The time is measured for a fixed volume of the liquid to
Capillary Viscometer
be drawn up through a straight open-end capillary tube by
E1 Specification for ASTM Thermometers
means of vacuum, under closely controlled conditions of
E77 Test Method for Inspection and Verification of Ther-
vacuum and temperature. The apparent viscosity in poises is
mometers
calculated by multiplying the flow time in seconds by the
3. Terminology
appropriate viscometer calibration factor or calculated viscom-
eter constant.
3.1 Definitions:
3.1.1 apparent viscosity—thedeterminedviscosityobtained
5. Significance and Use
bythetestmethodunderdescription.Viscosityistheresistance
5.1 This test method is useful for characterizing the flow
to deformation or internal friction of a liquid expressed as the
behavior of asphalt emulsion residues and non-Newtonian
bitumens. However, since non-Newtonian viscosity values
This test method is under the jurisdiction of ASTM Committee D-4 on Road
depend on the level of shearing stress, its duration, and the
and Paving Materials and is the direct responsibility of Subcommittee D04.44 on
shear history of the material, a non-Newtonian viscosity is not
Rheological Tests.
a unique material property. Instead, it is a parameter which is
Current edition approved Sept. 10, 1995. Published November 1995. Originally
published as D4957–89. Last previous edition D4957–94. characteristic of the fluid-viscometer system under the condi-
Annual Book of ASTM Standards, Vol 04.03.
tionsofthemeasurementprocedure.Therefore,comparisonsof
Annual Book of ASTM Standards, Vol 14.03.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4957–95
FIG. 1 Typical Log-Log Rheogram Plot with Example
non-Newtonian material behavior should only be made using 6.2.2 It is essential that liquid-in-glass thermometers be
apparent viscosities determined in similar viscometers under calibrated periodically using the technique given in Test
similar conditions of shearing stress and stress history. Proce- Method E77 (see Appendix X1).
dures of sample preparation are especially important for 6.3 Bath—A bath suitable for immersion of the viscometer
repeatability or reproducibility of test results. sothattheliquidreservoirorthetopofthecapillary,whichever
is uppermost, is at least 20 mm below the upper surface of the
6. Apparatus
bath liquid, and with provisions for visibility of the viscometer
andthethermometer.Firmsupportsfortheviscometershallbe
6.1 Viscometers—Capillary types, made of borosilicate
provided.Theefficiencyofthestirringandthebalancebetween
glass, annealed, suitable for this test are as follows:
heat loss and heat input must be such that the temperature of
6.1.1 Modified Koppers Vacuum Viscometer,asdescribedin
the bath medium does not vary by more than 60.05°F
AnnexA1. Calibrated viscometers are available from commer-
(60.03°C) over the length of the viscometer or from viscom-
cial suppliers. Details regarding calibration of viscometers are
eter to viscometer in the various bath positions.
given in A1.3.
6.4 Vacuum System—A vacuum system capable of main-
6.2 Thermometers—Calibratedliquidinglassthermometers
taining a vacuum to within 60.5 mm of the desired level up to
of an accuracy after correction of 0.04°F (0.02°C) can be used
and including 500 mm Hg. The essential system is shown
or any other thermometric device of equal accuracy. ASTM
schematicallyinFig.2.Glasstubingof6.35mm( ⁄4in.)inside
Kinematic Viscosity Thermometers 47F and 47C are suitable
diameter should be used, and all glass joints should be airtight
forthemostcommonlyusedtemperatureof140°F(60°C).See
so that when the system is closed, no loss of vacuum is
Test Method D2171, Table on Kinematic Viscosity Test
indicated by the open-end mercury manometer having 1-mm
Thermometers for details on specific thermometers.
graduations. A vacuum or aspirator pump is suitable for the
6.2.1 The specified thermometers are standardized at“ total
vacuum source.
immersion”,whichmeansimmersiontothetopofthemercury
6.5 Timer—Astopwatchorothertimingdevicegraduatedin
column with the remainder of the stem and the expansion
divisions of 0.1 s or less and accurate to within 0.05% when
chamber at the top of the thermometer exposed to room
tested over intervals of not less than 15 min shall be used.
temperature. The practice of completely submerging the ther-
Electrical timing devices may be used only on electrical
mometer is not recommended. When thermometers are com-
circuits the frequencies of which are controlled to an accuracy
pletely submerged, corrections for each individual thermom-
of 0.05% or better.
eter based on calibration under conditions of complete
6.5.1 Alternating-current frequencies that are intermittently
submergence must be determined and applied. If the thermom-
and not continuously controlled, as provided by some public
eter is completely submerged in the bath during use, the
pressure of the gas in the expansion chamber will be higher or
lower than during standardization, and may cause high or low
The vacuum control system marketed by Cannon Instrument Co., P.O. Box 16,
readings of the thermometer. State College, PA, 16801, has been found satisfactory for this purpose.
D4957–95
8. Procedure
8.1 Follow the general procedure described as follows,
however, the specific details of the Modified Koppers viscom-
eter are described in Annex A1.
8.1.1 Maintain the bath at the test temperatures to within6
0.05°F (60.03°C). Apply the necessary corrections, if any, to
all thermometer readings.
8.1.2 Select a clean, dry viscometer that will give a flow
time between 50 and 200 s for the C zone of a Modified
Koppers viscometer. Preheat the viscometer filling tube and
capillarytubeseparatelyintheovenat383 64°F(195 62°C)
for 5 min to assist in eliminating air bubbles when the sample
is poured.
8.1.3 Charge the viscometer filling tube by pouring the
prepared sample to within 62 mm of the fill line.
NOTE 5—In cases where highly viscous materials are being tested, the
possibility of air entrapment in the sample is greater. To alleviate this
problem,aslightvacuumonthefilltubebeforethecapillarytubeisplaced
in position is suggested. This can be accomplished using a light vacuum
source attached to the fill tube for 30 s. A simple cork and tube should
suffice to achieve the desired effects.
8.1.4 Place the charged viscometer filling tube in an oven
maintained at 383 6 4°F (195 6 2°C) for a period of 10 6 2
min to allow large air bubbles to escape.
8.1.5 Remove the viscometer filling tube and capillary tube
fromtheovenandthenproperlypositionthecapillarytubeinto
FIG. 2 Suggested Vacuum System for Vacuum Capillary
Viscometers the filling tube. Insert the viscometer in a holder and position
theviscometerinthebathsothattheuppermosttimingmarkis
at least 20 mm below the surface of the bath liquid.
power systems, can cause large errors, particularly over short
NOTE 6—Capillary action on certain small-diameter viscometer tubes
timingintervals,whenusedtoactuateelectricaltimingdevices.
may cause a rise of the sample above the first timing mark. If this is a
6.6 Sample Preparation Oven—A suitable oven for semi-
problem, the capillary tube should be withheld from contact with the
continuous operations with control of temperature up to 396 6
sampleforafewminutespriortorunningthetest,thenpositionedquickly
4°F (202 6 2°C) is required. It should have a fast heating rate
and allowed to equilibrate a minute or two.
capability in order not to delay testing when needed on short
8.1.6 Establish the vacuum to within 60.5 mm of the
notice.
desiredlevelandconnectthevacuumsystemtotheviscometer
with the toggle valve or stopcock closed in the line leading to
7. Sample Preparation
the viscometer.
7.1 Asphalt Emulsion Residue—Ifthesampleistheresidual
8.1.7 After the viscometer has been in the bath for 306 5
product from the emulsion distillation test at 500°F (260°C),
min, start the flow of asphalt in the viscometer by opening the
pour a suitable portion of the total residue into a 50-mLbeaker
toggle valve or stopcock in the line leading to the vacuum
and allow to cool to 356 6 9°F (180 6 5°C). Then stir this
system.
portion of the sample at 1 r/s for 10 s. Following this, pour the
8.1.8 Measure to within 0.1 s the time required for the
proper amount into the viscometer as in Section 8. Alterna-
leading edge of the miniscus to pass between successive pairs
tively, allow this portion of the residue to cool completely and
of timing marks.
set aside for future testing. This material should then be
8.1.9 Upon completion of the test, clean the viscometer.
handled as in 7.2.
There are numerous methods that can be used. Two suggested
7.2 Ambient Sample—Heat the sample in an oven main-
methods are given in A1.4 and A1.5.
tained at 383 6 4°F (195 6 2°C). Stir the sample occasionally
until homogeneous and pour into a 50-mL preheated beaker.
9. Calculation
Stir the sample at approximately 1 r/s for 10 s.
9.1 Select the appropriate viscosity constant for any set of
NOTE 3—Because of the nature of some asphalts and asphalt emulsion timing marks from the calibration constants given by the
residues, their shear and thermal history prior to testing may cause
manufacturer.
variations in test results. Careful sample preparation is most important for
9.1.1 Using these appropriate viscometer constants, calcu-
consistent test results.
lateandreporttheapparentviscositytothreesignificantfigures
NOTE 4—In cases where the asphalt is not sufficiently fluid to pour at
according to the following equation:
356°F or too fluid to pour without splattering during transfer into the
viscometer; other pouring temperatures may be used providing there is Apparent Viscosity, h 5 K ·t (1)
zone zone
agreement between interested parties.
D4957–95
where: where:
h = apparent viscosity in poise for particular timing h = headofliquidinthecapillaryatthemidpointof
zone, thezone(mmofHg)foundinAnnexA1,Table
t = time it takes the asphalt meniscus to traverse the
A1.1
particular zone or interest in seconds, and [K ] = viscometer constant in P/s,
zone 1
K = viscometer constant for the particular timing zone [K ] = viscometer constant for the vacuum applied in
zone zone 2
in P/s. P/s,
P = nominalvacuumapplied,generally,300mmof
9.1.2 The shear rate associated with this apparent viscosity
Hg, and
is calculated according to the following equation:
P = vacuum applied (mm of Hg),
Shearrate, 8g 54 Ls /Rt 5 Shear Constant/t (2)
zone
9.2.1 Repeat the computation procedure of 9.1 for the times
obtained with the new vacuum. Decrease the vacuum to
where: increase the time of flow for materials that are too fluid.
−1
g = shear rate in reciprocal seconds, s
Alternatively,vacuummaybeincreasedtoreducetimeofflow
R = tube radius in mm,
for materials that are too viscous. Report the test conditions
L = length in mm of the zone for which the time was
with the results.
recorded,
9.3 The apparent viscosity, h, from 9.1.1 may be plotted
t = time in the zone in seconds, s, and values for shear
against the shear rate on log-log coordinates to obtain a
constant are found in Table A1.1.
rheogram or plot illustrating the variation of viscosity with
9.1.3 If desired, a mean shear stress may be calculated from
shear rate. The B zone value does not necessarily reflect the
the following equation:
apparent viscosity of the material. An example rheogram is
Shear Stress,t5h·g (3)
sh
...