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

destruction of the polymer modifier. As has already been demonstrated, the effective
length of storage of polymer modified asphalt emulsions, even under ideal conditions,
can vary widely depending upon the modifier and bitumen types, and the degree of
polymer-asphalt compatibility. When storing and handling prepared asphalt emulsions,
the following general guidelines are recommended:
• In general, store the emulsion between 10º and 85º C. depending upon the
intended use and the particular grade of emulsion being utilized;
• Do not heat the emulsion above 85º C. during storage as this may cause excess
water evaporation. Similarly, excessive and prolonged temperatures above 100º
C. can cause breakdown of the emulsion and/or destruction of its polymer
components;
• Avoid prolonged periods of storage, and make sure the mixture is gently and
continuously agitated;
• Maintain an accurate temperature history and collect frequent measurements;
• Do not allow the asphalt emulsion to freeze, as this breaks the emulsion and
causes phase separation and mixture instability; and,
• Do not use forced air to agitate the emulsion as this too may cause it to break
prematurely (1, 51, 52).
DSR testing conducted after simulated aging with a Rolling Thin Film Oven (RTFO-
DSR) of properly cured polymer modified emulsion residue indicates that unmodified
asphalt emulsion contamination present within storage tanks or product transfer lines
may adversely impact performance (52). Similarly, some reductions in RTFO-DSR
performance were noted with increasing storage times, which, when combined with
product contamination, resulted in even more pronounced degradation of RTFO-DSR
results (52, 53).
However, when modified non-emulsified asphalt binders were tested using comparable
protocols, results indicate that the impact of prolonged storage, elevated temperatures,
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