Using Polymer Modified Asphalt Emulsions in Surface Treatments A ...

temperature ranges. DSR testing distinguishes between elastic (recoverable)
and viscous (non-recoverable) responses of the test material when placed under
stress, and is often used as an indicator of rutting resistance, and other forms of
permanent deformation.
• Bending Beam Rheometer (BBR) and Direct Tension Test (DTT) – BBR and DTT
testing are used to determine the stiffness/flexibility of asphalt binders at low
temperatures, and thus, their susceptibility to thermal cracking.
• Ring and Ball Softening Point – Used to determine the temperature at which full
penetration of the modified asphalt occurs. This test provides another measure
of high temperature susceptibility.
• Direct Tensile Test – A measurement of the force that is required to deform an
asphalt sample, tensile strength testing allows the stress applied to the sample to
be plotted against its resulting elongation (or strain).
• Elasticity after Ductility Testing – In this test, the sample is elongated into a
thread, cut, and the resulting recovery measured. Elasticity measures have
important implications related to the resiliency of the pavement under repeated
cycles of loading and unloading.
• Rotational Viscometry (RV) – RV is utilized to measure the viscosity of a PMA,
and is directly related to the workability of the mixture during field application.
Modified asphalt emulsion testing can be carried out by either testing the binder prior to
emulsification, or by obtaining a sample of the properly cured emulsion residue. A more
thorough treatment and evaluation of performance testing methodologies and criteria is
provided in Section 2.4.
2.2 Types of Polymer Modifiers
2.2.1 Overview and Classification
Polymer modifiers are generally separated into two broad categories: elastomers and
plastomers - based upon their strain performance characteristics at low temperatures.
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