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

1.0 INTRODUCTION
1.1 Background
Polymer modification of asphalt emulsions offers improvements in performance and
durability, mitigation of pavement distress, and reduced life cycle costs when compared
to unmodified asphalt emulsions or hot mix asphalt surface dressings. Polymers have
exhibited demonstrable reductions in rutting, thermal cracking, and increased resistance
to many forms of traffic-induced stress. Conversely, polymer modifiers, when used in
chip seal applications, have demonstrated some problems associated with accelerated
stripping when placed over a moisture sensitive hot mix. Asphalt emulsions frequently
provide a lower cost, efficient, and more environmentally-friendly alternative to hot
mixes due to their low energy consumption, reduced hydrocarbon emissions, ease of
implementation at remote sites, and preventive maintenance/life-extending benefits
when applied to mildly distressed pavements.
Although best-practice manuals and specifications for conventional asphalt emulsions
are plentiful, there is no single document available which offers guidance on the proper
use, application techniques, and benefits of high-performance polymer modified asphalt
emulsions. Similarly, the preponderance of the published research on polymer
modifiers has focused primarily upon their use in hot mix asphalt (HMA) applications.
This research includes an exhaustive review of the literature to collect and analyze
polymer modified emulsion practices and specifications, coupled with a laboratory
testing and verification program designed to validate the findings and recommendations
developed from the literature review. Guidance is provided on proper project selection,
polymer dosing rates and methods, applicability under varying traffic load and
environmental conditions, and contraindications to the use of polymer modifiers.
1.2 Study Objectives
The principal objectives of this study were to:
1