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Page 16

Contractors World International Vol 6 No 1

Bageci tunnel project manager Luc Bosmans said:

“Due to the special safety and environmental

demands and lack of space, hydrodemolition was

really our only option from the very start. We

thought it was going to be the most productive

method for this tunnel work, and it proved to be

very efficient.”

In total, the Conjet Robot 365, together with the

Hammelmann pump operating up to a pressure of 1200 bar,

worked 1,370 hours in the Biéreau tunnel and selectively

removed 1,610 m³ of defective concrete from the tun-

nel circumference at an average depth of 80 mm to 100

mm. The total area treated was approximately 17,000


Bageci also removed the concrete debris, damaged

rebar and applied new high quality concrete on the

tunnel lining.

“This restoration has been completed in 220 days

with the Conjet Robot demolishing and removing

concrete at a rate of about 1.35 m³/h. In my

opinion this is an excellent result,”

said Luc Bosmans.

Bageci site manager, Sandro Bonsiambiante, added:

“Throughout the tunnel the concrete has been

harder and more resistant in some places, but with

the auto regulation the Conjet robot selectively

demolished and removed only the damaged

concrete to the right depth over the entire surface.

“Another advantage was the high availability

of the equipment. There is a lot of environmental

dust and wear and tear on equipment in this kind

of application and the spare parts supply has been

excellent with no serious break downs.”

Conjet Configuration

The Conjet Robot 365 consists of a carrier that includes

pulse monitored drive wheels, electric and hydraulic sys-

tems and a simple, easy to use control system. The car-

rier can be equipped with optional attachments, such as

standard feed beam, tower or a rotor assembly and can

also be operated by a wireless control.

The cutting head features a 45º attack angle of the jetting

lance as standard, variable oscillation width and encoders

for lance turning and cradle position.

Relining the Tunnel

Bageci chose, after consulting Grouttech, a dry mortar

projection technique to re-

line the exposed reinforce-

ment. The client had previous

positive experience using this

system due to its unmatched

quality and ease of application.

By applying the grout, un-

der high pressure, through a

capillary nozzle, Grouttech en-

sured a high quality shotcrete

(C45) injection was achieved.

Two 30 t. capacity batch silos

were installed on flatbed rail

wagons to provide a close sup-

ply system. This enabled maxi-

mum use of time as the work

continued 24 hours a day.