Formulated for success
HBB was contracted to provide the following:
- High-performance products, which were produced to exacting standards for two very different concrete types. A low-resistance concrete was specially developed to enable pumping across long distances in an underwater environment and was used to replace a thick layer of soft sludge on the canal bed a few meters above the planned tunnel.
- Concrete delivery and pouring. A crucial phase of the construction spanned four days and three nights in May 2010, with 12,508 cubic meters of concrete from the two Merksem and Kieldrecht HBB plants being delivered and poured by approximately 60 mixers, each of which made 40 round trips over the long weekend. The average production rate per plant was 80 cubic meters per hour, with a peak of over 100 cubic meters per hour. Seven shifts of 100 staff drove the pour onward, with a passionate commitment to the job and the client evident at the site throughout the weekend.
- A second major pour of approximately 16,000 cubic meters of steel-fiber-reinforced concrete was used to create a strong cap over the softer concrete placed in May. 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, thereby protecting the integrity of the tunnel below. For this phase of the job, all hands were on deck once again to produce and then deliver the concrete to the underwater site, with the pour requiring 880 mixer round trips over another four days of intensive activity.
This massive operation was accomplished to the customer’s satisfaction, with all delivery and pouring coordination carried out smoothly without the slightest incident – a large-scale challenge that was met by all involved.