How does DUSTAC work?
DUSTAC•
assists with dispersing smaller
particles – aids distribution during
compacting, reducing the soil pore
volume
• enables less water to be used
for optimal compaction – as with
concrete plasticising effect
• coats the particles
• makes any contacting particles stick
together on drying because of the
DUSTAC coating on the surfaces,
and
• achieves best performance at the
highest compaction.
Benefits of using DUSTAC
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DUSTAC• is environmentally friendly
• suppresses unwanted road dust
(better visibility/safer driving
conditions)
• provides hard, smooth, dust-free
roads and surfaces
• ensures excellent traction in wet and
dry conditions
• significantly reduces vehicle wear
and road maintenance costs
• saves water significantly through
operational life of roads
• is a simple, user-friendly application
method
• uses existing equipment
• reduces P.I. in material significantly,
and
• dramatically improves CBR of
treated wearing courses.
Approximate dilution
guidelines
•
•
•
•
•
Clay – 10% for easy penetration
Normal aggregate – 15%
Soil sand – 20%
Very porous material – use a thicker
solution for penetration
Very dense material – use a more
desIgn Namibia October - December 2013
diluted solution for penetration.
Soil compaction
When constructing a road, proper
compaction is of cardinal importance
to obtain maximum performance and
life expectancy. Determining the OMC
(Optimum Moisture Content) for the
particular soil geology will be required
to then work out the compaction ratio
or CBR (California Bearing Ratio) that
will yield the best performance for the
materials available. Site conditions
will vary and each needs to have an
assessment done to determine the
appropriate course of action. Mix-in
application of DUSTAC during road
construction has proved to be effective
and assists with the quality of the
road once completed. Once the top
layer has been properly compacted,
the application of DUSTAC will assist
in reducing the loss of quarry material
under traffic due to dust generation.
Quarry material is a non-renewable
resource and will become harder
and more expensive to obtain due
to haul distances to borrow pits to
reconstruct the road surface once it has
deteriorated.
Road preparation
The preparation of the road is also
dependent on site conditions. Marshy
areas require drainage works and
stabilisation whereas sandy soils
require addition of graded aggregate
for building a stable base or sub-grade
layer. Top soil and vegetation have to
be stripped off to reveal a more stable
platform on which to construct the road.
The importation of quarry material from
an approved borrow pit is an expensive
operation. DUSTAC allows for the use
of local/on-site materials, achieving
similar/better results through chemically
improving the CBR of the materials
used. The maintenance of the road