Sand and gravel: the two indispensable ingredients for the 'blocs'

On the Wadden Sea side, the dike will be raised by almost 2 meters and reinforced with Levvel blocks. Innovative and above all extremely strong concrete blocks that hook together like Lego blocks and break the waves when it storms hard. Spaansen Industriezand en Grind supplied two important ingredients for the Levvel-blocs: sand and gravel.

The production of the 70,000 Levvel blocks requires a lot of sand and gravel. To be exact; 140,000 tons of sand and 240,000 tons of gravel. "The sand is somewhat coarser in structure," says Johan Spaansen, director of Spaansen and the third generation at the helm of the family business. "We get this so-called concrete sand from the North Sea. For this we deploy, among other things, the YED PRIOR, the largest vessel in our fleet that extracts gravel and sand. We rinse and sieve the material we dredge and then sort it into various sizes. This also applies to the gravel we delivered."

Efficient delivery

The Levvel blocks were produced in a temporary, purpose-built factory in Harlingen with a run of about 100 blocks per day in a fully automated process. The site next to this factory is home to Spaansen Industriezand and Grind. "From the sea we transport the sand and gravel to our own site. Here we sort it to then transport it by truck to our neighbor, the Levvel plant. In total, this involves some 11,000 trucks that only have to travel a short distance. An additional advantage is that we are not affected by the low water levels in the rivers. By the way, all our vehicles are Euro 5 and Euro 6 powered and we have been the leader in load capacity for years because we have in-house bodywork construction. To guarantee the continuity of the production process of the concrete blocks, we have specially maintained an internal stock on our premises." Spaansen's sand and gravel is not only found in the Levvel blocks, it also serves as a firm and solid bed of coarse gravel for the underwater concrete. "This gravel has a coarse structure so it wears well on the gravel," says Spaansen.

Concrete for construction

In addition to storing sand and gravel in Harlingen, Spaansen built a new concrete plant here in 2018. Here the family business produces, delivers and assembles prefabricated walls and shells for residential construction under the name Spaansen Bouwsystemen. "Our family business has grown big over 75 years through entrepreneurship and connection. The expansion into building systems is a great recent example of this. The concept is called Facade Ready in which robots are used to produce ready-made house facades
be made."