TM
5-822-14/AFJMAN
32-1019
g. Curing. Curing presents the greatest problem
ly aerated, it cannot be compacted to accept-
able limits. The Asphalt Institute has deter-
in asphalt soil stabilization. The Asphalt Institute
mined that the mixture has sufficiently aerated
has determined that the rate of curing is depen-
when it becomes tacky and appears to "crawl."
dent upon many variables: quantity of asphalt
Most aerating occurs during the mixing and
a p p l i e d , prevailing humidity and wind, the
spreading stage, but occasionally additional work-
amount of rain, and the ambient temperature.
Initial curing must be allowed in order to support
ing on the roadbed is necessary. The Asphalt
Institute has reported that overmixing in central
compaction equipment. This initial curing, the
evaporation of diluents, occurs during the aeration
plant mixes can cause emulsified asphalts to break
early, resulting in a mix that is difficult to work
stage. If compaction is started too early, the
in the field.
pavement will be sealed, delaying dehydration,
f. Compaction. Compaction should begin when
which lengthens the time before design strength is
the aeration of the mix is completed. The Asphalt
reached. The heat of the day may cause the
Institute recommends that rolling begin when an
mixture to soften, which prohibits equipment from
placing successive lifts until the following day.
emulsified asphalt mixture begins to break (color
change from brown to black). Early compaction
This emphasizes the need to allow sufficient cur-
ing time when lift construction is employed. The
can cause undue rutting or shoving of the mixture
Asphalt Institute recommends a 2- to 5-day cur-
due to overstressing under the roller. The density
ing period under good conditions when emulsified
of emulsion stabilized bases has often been found
bases are being constructed. Cement has been used
to be higher than that obtained on unstabilized
to accelerate curing.
bases for the same compaction effort.
5-3
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