Stabilization Selection Guide for Aggregate - Illinois Department of ...

CHAPTER THREE
Mechanical Stabilization
Mechanical Stabilization
INTROdUCTION
Mechanical stabilization covers everything from compacting
and blending soils, to incorporating any of a vast assortment
of conventional geosynthetics, to using (installing, placing,
incorporating, blending) less conventional materials, such as
woodchips, sawdust, and woodmats, to aid in meeting the required
strength. This section references tables that provide information
on conventional and less conventional mechanical-stabilization
techniques.
SELECTING A MECHANICAL-STABILIZING TECHNIqUE
Compaction and geosynthetics are the most widely used and
accepted mechanical-stabilizing techniques. Appendix table H.1
provides a comprehensive listing of issues and concerns, such
as serviceability, safety, environment, and cost for three selected
mechanical-stabilization categories: cellular confinement, fiber
reinforcement, and geotextile/geogrid reinforcement (FHWA 1995).
The chapter also briefly discusses several less conventional
and far less used techniques. Appendix table H.2 is a decision
matrix resulting from a military test in which many of these less
conventional expedient stabilization techniques were evaluated
(Kestler et al. 1999). Although military and forest roads may differ
in purpose, some of these stabilizing surfaces could be used
within the Forest Service for temporary roads over soft ground and
localized sections requiring stabilization. The emphasis here is on
localized sections; the surfaces are generally not recommended
as a stabilization technique for a road of any length. The table
provides rankings on factors such as traction, equipment required
for construction, life expectancy, ease of walking/foot traffic, etc.
Ashmawy et al. (2006) provide a comprehensive assessment of
various recycled materials that can be used to stabilize marginal
soils in Florida. Such materials include scrap tires and slag because
of their relatively low cost and desirable engineering properties.
These less conventional techniques may provide viable alternatives
to more costly standard stabilization techniques, but require sound
engineering judgment and good management practices.
Compaction
Compaction is the most basic of the mechanical-stabilization
techniques. Proper compaction is essential. It increases density
thus lowering the potential of increased moisture content, even in
case of saturation. Both increased density and decreased moisture
content potentially increase strength.
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