Floor slabs just in time for Belgium‘s housing construction industry

With 372.8 inhabitants per km², Belgium is one of the most densely populated countries in the world, ranking eleventh even before Germany or France. Most of the 11.4 million citizens live in large cities and the outskirts. The demand for homes, especially in social housing construction, is growing intensively. „In Belgium, 80% of the residential buildings are more than 20 years old. We have a backlog demand; therefore, the construction industry is booming and the construction projects of our customers are getting bigger,“ also reports Patrick Vos, owner and general manager of the building material specialist Daerden. „Over the next years, the local government of Wallonia will invest more than 240 million Euros in social housing construction alone.“

„Construction companies and architects all over Belgium are more and more opting for the precast construction system,“ states Patrick Vos. Fixed schedules for construction projects and industrially controlled processes in pre-production ensure a reliable construction progress in shorter periods. „So far, we have been producing hollow-core slabs as well as customized concrete elements such as columns and beams for customers throughout Wallonia with great success. We are always aiming at delivering our customers, on short notice within 24 hours, if required. However, the demand for prefabricated semi-precast components, especially floor slabs, increased above all for large-scale construction projects in the last one to two years. We have reacted to this demand accordingly.“

Production process flexibly adapted to the order situation

In 1995, the concrete factory of Daerden was a real pioneer in the newly developed Op´t Reeck industrial zone in Riemst near Maastricht. Today, almost 25 years later, the company continues to expand. They acquired another plot of land covering 4.19 hectares next to the previous main building in 2017. „Away from a mere stationary solution and towards to a modern plant concept for the production of floor slabs with flexible processes and latest technology,“ as outlined by Philippe Marrié, project sales manager at the concrete plant specialist Vollert, supplying the know-how and the plant equipment as an experienced general contractor.

In a circulation system up to 20 shuttering pallets are permanently circulating at the same time. „Maximum plant productivity on a floor space of 63 x 20 m,“ Philippe Marrié adds. More than 100,000 m² of floor slabs will be produced per year in future. „We guarantee our customers maximum delivery capability. It must be possible to produce elements in different lengths and widths just in time. We have to react to this on short notice, being in the position to adapt the plant processes and pallet loadings as quickly as possible,“ states Bart Thijs, technical manager at Daerden. For this purpose, we are able to manufacture several floor slabs of different sizes on one circulation pallet (13 x 2.8 m) simultaneously, with only the lateral side formwork being permanently mounted. The storage as well as production processes are centrally controlled by the VCC (Vollert Control Center) production control system, which creates the order scheduling list, optimizes pallet loadings, determines the storage and retrieval sequences, and manages the curing times and loading processes. Now, statistical evaluations of plant efficiency are available at any time. Printouts of labels or reports ensure transparency of the production process and facilitate the storage location management.

The right degree of automation is decisive

Before manually positioning the shuttering profiles and installing the reinforcement truss girders, a large-scale Smart Plot plotter applies color according to the CAD/CAM specifications, precisely outlining the contours of the floor elements. A Smart Cast concrete spreader places the precisely specified amount of concrete, while hydraulically actuated flat slide valves can block out individual partial areas, for example, block-outs used for electrical or sanitary installations. For concrete compaction a Smart Compact² vibrating station is used, ensuring a smooth exposed concrete surface on the underside. This process is carried out at low frequency, hence without any large generation of noise, which was required because of the proximity of the Op´t Reeck industrial zone to an adjacent residential area. Afterward, a roughening unit is used to roughen the upper surface for a better bond to the cast-in-situ concrete.

Another technical highlight is the fully insulated Vario Cure curing chamber with two rack towers placed in-line. The tandem design of the rack system equipped with 17 pallet compartments placed on top of each other and an intermediate passage level provides an especially innovative, space-saving concept. After concrete placement, the freshly concreted floor slab moves into the intermediate level of the curing chamber at ground level, another one can follow in a row. „Here a particular feature is the fact that eight rack bays are beneath the entrance level and nine rack bays are above the same,“ explains Frank Langenfeld, project manager at Vollert. A stationary Vario Store storage and retrieval unit, installed centrally behind the two rack towers, takes over the floor slab that is moved in first, with a special coupling system carrying the second floor slab into the front rack tower.

Well-equipped for the future

„This plant concept is characterized by state-of-the-art technology and a proper degree of automation,“ Patrick Vos summarizes. „In particular, due to the flexible working processes, we are in the position to respond quickly to changing order situations. And, of course, to deliver top quality to our customers.“ Plant components that have stand the test in practice for many years in combination with detailed further developments and a customer-oriented preliminary planning enabled the implementation of the overall new construction project in an extremely short period of a few months, from the project request through to the commissioning. „After only eight weeks, 70% of the maximum production capacity were already achieved,“ Vos says.

„We are very glad to have increased the number of our satisfied customers with Daerden and wish Mr. Vos and his team a successful future,“ Phillip Marrié adds.