Page 35 - MODELING OF ASPHALT CONCRETE

Modeling of Asphalt Binder Rheology and Its Application to Modified Binders 13

Standard Purpose of Test and Applicability for Modified Asphalt
Test Protocol Binders (MABs)
Index (Empirical) Tests
Softening Point ASTM D36 An index of consistency at very high temperatures.
(R&B) Used widely around the world for compliance but not
considered reliable for assessing the high temperature
performance in paving applications.
Test can be used to measure instability of modified
asphalts.
Penetration @ ASTM D5 Considered an index for consistency of binder at
25°C (dmm) NF T intermediate temperature. Although test is questionable
66-004 and of little value, it is used in many MAB specifications
in Europe, Australia, and Japan. The effect of modifiers
can be an increase or a decrease in penetration.
Frass Breaking IP 80 An index of resistance to cracking at low temperatures
Point under repeated flexing and reducing temperature. Test
is mostly used in Europe as an indicator of brittleness.
Modifiers are known to result in decreasing Frass point,
particularly for elastomers.
Viscosity (Resistance to Flow) Tests
Rotational ASTM A measure of resistance to flow at production and
Viscosity @ 135– D402 construction temperatures of HMA. Used widely to
165°C measure workability of MABs.
Absolute ASTM Measured using the capillary tube under vacuum.
Viscosity @ 60°C D2170 Because many modified asphalts are non-Newtonian,
it has been used with caution and is not used in
specification widely. Modifiers are known to increase
the value of this viscosity and also increase shear rate
dependency.
Cone and Plate ASTM Developed to measure creep response under
Apparent Viscosity D3205 increasing creep loads to estimate apparent viscosity
@ 25–60°C at intermediate to high temperature. Not used widely
and standard was discontinued in 2000. Most polymer
modifiers are expected to increase viscosity.
Tensile (Extensional) Properties
Ductility @ 4°C and ASTM An index of flexibility at low temperatures when used at
@ 25°C D113 4°C. Also considered an index of compatibility particularly
when used at 25°C. Effect of modifiers on ductility varies
significantly depending on nature of modifier. Elastomeric
modifier tends to increase ductility at these temperatures,
plastomers have minimal or negative effect, and chemical
or oxidation tends to decrease ductility particularly at low
temperatures. Used in Europe at various temperatures.
Also used in North America in some states.

TABLE 2-1 List of Asphalt Traditional Tests