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

• Block Cracking;
• Rutting (caused by high pavement temperatures in combination with tight,
relatively stationary wheel turns); and
• Oxidation.
Cracking and oxidation are also found on hiking trails and bike paths, with the former
representing the most common and problematic form of distress.
FLH reports that slurry seals in particular, are the favored preventive maintenance
treatment applied to parking lot pavements, owing to their ability to waterproof the
underlying base pavement while reducing closed-to-traffic times, reducing energy
consumption, and minimizing environmental impacts.
As the research presented elsewhere in this report clearly illustrates, the use of PME in
thin surface treatments does appear to enhance stone retention, improve low
temperature susceptibility, and reduce the effects of high temperature deformation (i.e.,
rutting). Moreover, PME-based slurry has been anecdotally found to cure at a
somewhat faster rate than its non-modified counterparts (thereby reducing closed-totraffic
times). Thus, it is reasonable to conclude that the use of PME could be expected
to provide similar benefits in non-roadway applications, although it is not possible at this
time to assess the resulting cost-benefit implications.
2.8 Climate, Environmental and Timing Considerations
Serfass et al (1992) have examined the impact of climate on stone retention in surface
dressings using SBS-modified hot mixes and emulsified asphalt (18). In modified hot
mixes, the researchers note that an adequate period of warm weather is required to
facilitate the evaporation of aromatics to allow aggregate to “firm” into its final position.
The researchers recommend an application period extending from late May to late
August in northern or mountainous climates, and mid-May to mid-September in
southern regions for modified hot mix asphalt binders (18). Conversely, SBS-modified
emulsions were found to exhibit good stone retention characteristics even at relatively
cool temperatures and high humidity as determined through Vialit cohesive testing.
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