ASTM D7741-11

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Designation:D7741–11
Standard Test Method for
Measurement of Apparent Viscosity of Asphalt-Rubber or
Other Asphalt Binders by Using a Rotational Hand Held
Viscometer
This standard is issued under the fixed designation D7741; 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 2. Referenced Documents
1.1 The use of high viscosity asphalt binders like Asphalt- 2.1 ASTM Standards:
Rubber is becoming more common in the United States and D6114 Specification for Asphalt-Rubber Binder
worldwide.SpecificationssuchasSpecificationD6114notethe
3. Significance and Use
need for field control of the apparent viscosity and require the
use of a field production rotational viscometer. The testing of 3.1 This test is primarily used for field production control of
Asphalt-Rubber (A-R) and other high viscosity binders; how-
Asphalt-Rubber Binder for use in Asphalt- Rubber Hot Mix
and for Asphalt-Rubber Membrane is necessary to ensure ever the test can also be used in a laboratory setting.
3.2 Ahand held rotational viscometer is used to measure the
consistent mix properties that will ensure good performance of
these materials. Logistics of field applications limits the use of apparent viscosity of a completed blend of A-R or high
viscosity binder.Arotor (spindle), turning at constant speed, is
conventional laboratory controls and testing equipment. This
test, using a hand held rotational viscometer can be conducted inserted in the liquid binder to be measured. The resistance to
movementofthespindle(torque)causedbytheviscosityofthe
in either the field or laboratory to determine the apparent
viscosity of Asphalt-Rubber and other high viscosity binders surrounding liquid is measured using a special mechanism to
obtain direct readings in Pa·s or cP.
for field production control and to assess the uniformity of the
binder produced or for other related purposes.
NOTE 1—Spindle generally made of stainless steel, although another
1.2 Asphalt-Rubber Binder consists of a blend of paving
metal such as brass could be used.
grade asphalt cement and crumb rubber as described in
3.3 The measured apparent viscosity is used to control the
Specification D6114. Other high viscosity asphalt binders may
production of the A-R or other high viscosity binder, to assess
consist of asphalts modified with polymer or fiber or both.
the uniformity of the binder produced or for other related
Testing is performed following the specified reaction time, if
purposes.
any, within the production process. Control of the raw materi-
3.4 As the spindle turns in the A-R or other high viscosity
als is separate from the test.
binder,ithasatendencyto“drill”intothesample(i.e.,forA-R,
1.3 The values stated in SI units or inch-pound units are to
the spindle spins the rubber particles out of the measurement
be regarded separately as standard. The values stated in each
area).Consequently,theapparentviscositydropstoreflectonly
systemmaynotbeexactequivalents;eachsystemshallbeused
the liquid phase of the high viscosity binder. Therefore, the
independently of the other. Combining values from the two
peak viscosity measurement value is recorded to reflect the
systems may result in non-compliance with the standard.
viscosity of the blended material.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Apparatus
responsibility of the user of this standard to establish appro-
4.1 Viscometer—hand held rotational type viscometer (see
priate safety and health practices and determine the applica-
Fig. 1). The viscometer shall be equipped with a level bubble
bility of regulatory limitations prior to use.
to ensure proper orientation of the viscometer in the sample to
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 For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Rheological Tests. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved Dec. 1, 2011. Published January 2012. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
D7741–11
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D7741–11
FIG. 1
be tested. Spindle (rotor) speed typically 62.5 rpm, however
may vary with different manufacturers.
4.2 Spindle (Rotor)—Diameter - 24 6 1.1 mm. [1.0 6 0.05
inch]; Height - 53 6 0.1 mm [2 6 .005 inch] or equivalent (see
Fig. 2).
4.3 Thermometer—Digital with metal jacket probe, 1 de-
gree °C [2 degree °F] precision.
4.4 SampleCan—4liter[1gallon]metalcanwithwirebale.
4.5 Viscosity Standard Oils—Calibrated in absolute viscos-
ity in Pa·s [centipoises cP] and in the range of 1.0 to 5.0 Pa·s
[1000 to 5000 cP].
4.6 Controllable heat source, such as a hot plate, gas stove
or burner, etc., to maintain the test temperature of the A-R or
high viscosity binder sample during viscosity measurement.
4.7 Viscometer holder—clean metal can or some type of
frame where the viscometer can be stored between tests.
5. Calibration Verification
5.1 Calibration of the rotational viscometer shall be verified
FIG. 2
prior to use at each site per manufacturer’s instructions using
the reference viscosity standard oils.
Obtain the sample from an appropriate sample valve located to
6. Sampling
intercept the normal flow of material during production.
6.1 The sample shall consist of at least 3 liters [0.75 gal] of Perform sampling and testing in close proximity to the plant
the completed mixture of A-R or other high viscosity binder. operation to avoid undue temperature loss during handling.
D7741–11
6.
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