WORLD NEWS
When placing dual-layer concrete on
Germany’s A7, the Wirtgen paving train
— comprising two SP 1500 slipform
pavers and the TCM 180i texture-curing
machine — is the key player.
The A7 is being widened between
Hamburg and Bordesholm from four
lanes to six, and in some places to eight,
to ensure that the motorway remains
an efficient traffic artery. Aiming to
create a pavement that would offer a
high degree of driving comfort while
withstanding the loads of heavy-goods
traffic, the motorway consortium Via
Solutions Nord and the joint venture
ARGE A7 Hamburg-Bordesholm opted
for steel reinforced concrete paving with
an exposed aggregate concrete surface
when widening the 60km stretch
located in the Schleswig-Holstein region.
BT Beton-Technik GmbH,
commissioned with the job, have
specialised in concrete pavement
construction for many years. Managing
director Mirko Pokrajcic has been relying
on technologies and machines from
Wirtgen for just as long: “I insist on
100% quality — and this is precisely
what Wirtgen has been delivering for
over 25 years,” says Pokrajcic.
Kick-off: well-rehearsed moves
This well-versed team was able to achieve paving rates of 400–500m in 12-hour-shift
operations.
A total of 41 curved electric internal
vibrators ensured optimum material
compaction by means of high-frequency
vibrations. Dowel bars were inserted into
the fresh, pre-compacted bottom-layer
concrete at 25cm intervals parallel to
the direction of travel, and tie bars were
inserted transverse to the pavement.
The top-layer of concrete was
simultaneously loaded by an excavator
into the receiving hopper of the belt
conveyor, transported over the top of
the first SP 1500, and deposited directly
on the bottom-layer of concrete ahead
of the second SP 1500. The second
machine then compacted the material by
means of 29 electric T-vibrators, as they
are known, while paving it in a 5cm-thick
layer. The duo from Wirtgen paved some
4 000m³ of concrete each day in this way.
Man of the match
Player No. 3, the TCM 180i self-
propelled curing unit, followed hot
on the heels of the pavers. With
working widths up to 18m, it is an ideal
teammate for the two SP 1500s and is
the team’s technical player. Its task is
to spray a special combination of anti-
evaporation agent and surface retarder
onto the new concrete pavement. The
anti-evaporation agent protects the
The concrete paving work was carried
out by two Wirtgen SP 1500 slipform
pavers. As the first paver advanced, its
inset mould laid the concrete slab as
specified, 14.5m wide and 23cm thick.
The exquisite technician
An aerial view of the dual-layer wet-in-wet concrete paving on the A7.
10
MARCH 2019
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