Versatile in precast concrete structures

The Blankenburg connection is a multifaceted project for Van Dijk Beton. The specialist in order-bound precast concrete structures produces and delivers, among other things, many hundreds of modular noise barriers, a large number of foundations for traffic support structures and a series of fire-resistant wall elements. And completely unique: special concrete wedges for the immersion tunnel, which have to be placed just two days after measuring.

Van Dijk Beton has long been producing the modular concrete noise barriers to a Rijkswaterstaat design. "Construction consortium BAAK approached us to supply a large series of noise barriers in a slightly modified form," says Marc Pijpers, general manager of Van Dijk Beton. "In fact, the idea was to build on the already existing screen. In this case, some 700 elements were poured with a fine cannelure structure only on one side instead of on both sides. Such an assignment suits us very well, because we can organize ourselves well on it. Moreover, we have our own mold construction and produce and maintain the molds all in-house. By the way, the elements were supplied through Holland Scherm."

Other than the noise barriers, Van Dijk beton is also supplying a large number of concrete structures on the Blankenburg connection, which will soon be hidden from view. "For example, on the project we are delivering our VDC piles, also called foundations for traffic bearing structures," continued Pijpers. "They are the 'blocks' on which the portals for the matrix signs are founded. We supply these VDC piers nationwide and have also made an extensive delivery on the Blankenburg connection. These are elements of some 25-30 tons each that were delivered by special transport." Slightly less heavy but at least as special are the fire-resistant wall elements at the Maas Delta Tunnel. "You won't see these elements later either, but they do have a function," says Paul de Vries, manager of sustainability and business development at Van Dijk Beton. "The elements fill the space between the columns (piers) supporting the roof and are produced according to a special recipe. The specific mixture creates slightly more air bubbles so that it can expand at higher temperatures. In this case, we did not have to use polypropylene fibers, because the walls are subsequently provided with a fire-resistant covering."

The sinking of both elements for the future Maas Delta Tunnel represents a milestone in the project. Van Dijk Beton also has an important role to play in this. "For this, we produce the wedge structure for sealing the closing joint. This acts as a spacer between the abutment and the immersed tunnel element and ensures that the element cannot move," explains Maarten Klein Gebbink, head of the business office at Van Dijk Beton. "It involves two sets of two wedges. The dimensions of the first one are known; the fitting wedges, on the other hand, can only be measured after the last element has been sunk. On Monday morning, we receive the dimensions, on which we adjust the mold and reinforcement baskets so that the element can be cast at great depth under water within two days. This, of course, also places special demands on the mixture."

"Our contribution to the Blankenburg connection gives a nice picture of the versatility of Van Dijk Beton," summarizes Pijpers. "On the one hand, we are strong in producing concrete products in large series, but on the other hand, we are also at our best when there are deviating requirements for dimensions, mixture composition and punctual delivery. And it becomes even more fun when the theme of sustainability can also find a place in it. Because there too we are leading the way."