DIGEST 2006 - Sabita

Figure 3: Layer temperature profile
In each case cores were taken
immediately before the next layer
was laid on top of it, and these
were analysed specifically for
compaction. During the whole
process the paving temperatures
in the back of the paver varied
between 110 and 125 0 C.
Construction of the pavement was
finished at approximately 04h30
(including the coring of the last
layer), and the road was opened
to traffic immediately.
No extraordinary precautions were
taken in the paving or compaction
processes. No dragging of the
paver or the appearance of a
“bony” mix, typical of paving at
these temperatures, was
observed. There were also no
problems experienced with hand
raking of the edges of the top
mat. Joints with the existing
pavement were smooth and tight,
and all building specifications were
met.
Long haul in NSW
Broken Hill is a town close to the
NSW border with South Australia,
approximately 550 kilometres
from Adelaide and 760 kilometres
from Dubbo. There are no asphalt
plants near Broken Hill, and if a
minor or medium sized paving
project is undertaken, asphalt
must be trucked over these vast
distances. This results in haulage
times of up to 10 hours or more,
depending on traffic conditions.
The alternative is concrete paving
which is not always an option due
to unstable road substrates and
heavy mining vehicles.
Unless a mobile plant is used, the
asphalt is normally heated up to
inordinately high temperatures (as
high as 185 0 C) and then is laid
only during the very hot months –
effectively December to January.
Any small abnormality in the
weather causes huge problems
and the window for pavement
construction or repair could shrink
considerably.
When the asphalt arrives on site it
is often extremely difficult to work
due to large heat loss suffered
during transport. If there are any
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