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CAPITAL EQUIPMENT NEWS
JANUARY 2016
6
COVER STORY
tie-in points and follows the edge of the
road from there. The pavement is pressed
home in a further pass. Dynamic compac-
tion is mainly used for the main compac-
tion process. The drums vibrate horizontally
(oscillate) or vertically (vibrate), thus signifi-
cantly increasing the effect of compaction.
The operation is completed by a final roll-
er pass that will “iron out” any remaining
irregularities in the asphalt pavement or
surface to produce a perfect surface finish.
STRUCTURAL MAINTENANCE, REPAIR
AND REHABILITATION
Roads are exposed to tremendous loads
that will sooner or later leave their marks
on them. A time will come when every road
will be in need of a general overhaul. But no
two damage patterns are alike. Replacing
the pavement is a standard procedure
when repairing roads. The challenge is to
ensure that only the damaged layers of the
road structure are removed, and to avoid
disruptions to traffic at the same time.
Under these conditions, cold milling is the
only viable option for many construction
projects.
COLD MILLING MACHINES HAVE REAL
BITE
The tools that cold milling machines use
for removing road layers were originally
developed for the mining industry. So-
called point-attack cutting tools, fitted to a
rotating milling drum on the underside of
the machine, bite into the road at precisely
the specified depth. No material is too hard
for these tools. Cold milling machines are
even capable of rehabilitating pavements,
whether asphalt or concrete. The material
is milled and then directly loaded on trucks
to be transported from site, all in one
single pass.
As traffic is often slow-moving in the area
of the job site, car drivers mock the massive
cold milling machines by saying that they’re
always first in the traffic jam. Few bear in
mind, however, that rehabilitation projects
using cold milling machines are mostly
carried out as mobile roadworks. Alterna-
tive methods would involve a much greater
effort. Cold milling of road pavements is un-
rivalled in terms of both logistics and speed
of execution.
ROAD MILLING MACHINES ARE TEAM
PLAYERS
Not all cold milling machines are as big as
a complete apartment. Some models are as
small as a passenger car. On many job sites,
machines of different sizes frequently work
as a team, each one playing its own aces.
The large milling machine removes the
large surfaces, while the small one takes
care of milling off the pavement around
“nuisances”, such as manhole covers or
kerbstones.
PAVING AND COMPACTING USING
PAVERS AND ROLLERS
Typical of rehabilitation methods using
cold milling is that the damaged pavement
layers are usually replaced with asphalt,
– irrespective of whether the distressed
pavement consisted of asphalt or concrete.
The new surface course or asphalt road
structure is paved by road pavers prior to
conventional compaction by rollers.