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CONSTRUCTION WORLD
MARCH
2015
PROJECTS AND CONTRACTS
“There are actually two contracts
that have been awarded back to
back to Murray & Roberts Infra-
structure. While the coordination
and planning of these simultaneous projects
represents a challenge in terms of logistics, it
is a significant testament to the capabilities
and expertise of Murray & Roberts Infrastruc-
ture,” Bennie Hook, project manager, says.
The scope of work on both contracts
consists of periodic maintenance of National
Route 2 (N2). The first contract is a 22 km
stretch, namely Section 23 from km 33 to km
55, which is roughly from the Umzinto River
to the Umkomaas River.
The second contract is a 14,5 km stretch,
namely Section 25 from km 2,7 to 17,2, which
is from where the N2 crosses the Umlaas
Canal to what is known as the Spaghetti
Junction. The first contract commenced in
August 2014, with a duration of 16 months,
while the second contract commenced
in September 2014, with a duration of 14
months and an estimated completion date
of November 2015.
Commenting on the pavement specifica-
tion, Hook says the projects consist of reha-
bilitation work on the old road surface. This
involves milling out a layer of the existing
asphalt and replacing it with new material,
followed by a final Ultra Thin Friction Course
(UTFC) layer on top.
A major feature of the project is the use
of a Comar mobile asphalt plant from Much
Asphalt, which is providing the Recycled
Asphalt Pavement (RAP) mix for the projects.
Both projects will use 40% RAP content.
“Recycling the old asphalt in this manner
represents a significant cost saving in terms
of bitumen and aggregate, as well as being
highly sustainable,” Hook comments.
“A particular challenge has been posed
by closely monitoring the binder content of
the existing asphalt, due to various rehabil-
itation work carried out over the years that
has used different materials.
“The project is pretty straightforward.
However, obtaining the correct RAP mix
is tricky, as the varying binder content of
the old asphalt affects the ratios of the mix
recipe. This has to be monitored closely as
quality control is critical.”
In terms of volumes, 21 000 t of continu-
ously graded fine mix and 23 000 t of contin-
uously graded medium mix will be used
on Section 25, in addition to 555 000 m
2
of
UTFC. A total of 33 500 t of continuously
graded course mix and 535 000 m
2
of UTFC
will be used on Section 23.
Equipment on site includes a paver,
a shuttle buggy, a milling machine, vibra-
tory roller and water cart. Hooks says that
Murray & Roberts Infrastructure has also
been employing local labour in terms of
SANRAL requirements.
>
MAKING INROADS
in KwaZulu-Natal
Murray & Roberts Infrastructure has secured its first roadworks
rehabilitation contracts in the province of KwaZulu-Natal for the
South African National Roads Agency Limited (SANRAL). This is a
major coup for the company, established after the integration of
Concor Civils and Concor Roads & Earthworks into a new single
business called Murray & Roberts Infrastructure.
ABOVE:
Rolling and paving of the longitudinal
joint.
CENTRE:
The new asphalt surface being laid
down by the paving train, comprising a dumper
truck, paving machine and tandem rollers.
BOTTOM LEFT:
The north-bound slow lane
being milled prior to being replaced with new
asphalt.
BOTTOM RIGHT:
The tack coat being sprayed
onto the milled surface.
“Recycling the old asphalt
in this manner represents a
significant cost saving in terms
of bitumen and aggregate,
as well as being highly
sustainable.”