Liefkenshoekspoortunnel in Belgium

The Liefkenshoekspoortunnel is the biggest construction project ever supplied by Holcim Beton Belgium.

The project to build a new railway tunnel under a sea-freight canal and a river to the north of
Antwerp started in 2008, and is projected to be completed by 2012. Holcim Beton Belgium (HBB) was contracted to supply high-performance products produced to exacting standards after listening carefully to the client’s detailed requirements for two very different concrete types. About 50,000 m3 of concrete needed to be poured in two weekends to stabilize and then to reinforce the bottom of the dock.

Formulated for success
The product requirement led to the development in-house of a specially formulated product
which can be pumped long distances, used in an underwater environment, and that offers low
resistance. This “low resistance” or
“low strength” concrete was used to replace a thick layer of soft sludge on the canal bed where the planned tunnel will run just a few meters below. The concrete was developed, tested and produced by HBB, specifically for the project.

Main phases of work
A crucial phase of the construction spanned four days in May 2010, with 12,508 m3 of concrete from the two Merksem and Kieldrecht HBB plants being delivered and poured.

Seven shifts of 100 staff drove the pour onward, with a passionate commitment to the job. Practically the whole company was involved in this massive operation, and the immediate feedback from the client was extremely positive.

The second major pour at the beginning of October involved 16,000 m3 of steel-fiber reinforced concrete used to create a very strong cap over the layer of softer concrete put in place earlier in the year. This cap is designed to resist the pressure of the bore head during construction and, after completion, the potential impact and weight of a large sunken vessel resting on it, in order to protect the integrity of the tunnel below. The custom concrete design was developed during several weeks of tests and features an incredibly high fiber density of more than 150,000 fibers/m3 (33 kg/m3).

For this phase of the job, all hands were on deck once again to produce and then deliver the concrete to the underwater site. The coordination of the delivery and pouring of this special product was carried out without the slightest incident, again to the great satisfaction of the customer.

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