Hillblock_Texel 2019 - photo courtesy of Hillblock/Marten Beton

To strengthen the dykes at the island of Texel, in the Northern part of the Netherlands, high density concrete blocks were installed along the coast.

The Netherlands has a relatively large coast and is known for having gained land from the sea. Therefore, this small country has many dykes they depend upon not to get flooded.

Dutch high water protection program

Due to climate change, we see a rise in seawater level. As around one-third of the Netherlands is below sea level, it is an important topic on the political agenda to keep the country protected. For this reason, different Dutch governmental institutions have created the ‘hoogwaterbeschermingsprogramma’ which translates into ‘high-water protection program’. The alliance of Dutch Water Authorities and ‘Rijkswaterstaat’ (Ministry of Infrastructure and Water Management) work together to strengthen the Dutch dykes for the water-safer Netherlands in 2050.

Revetment block for Dutch coast

A set of dykes north of the ‘Oudeschild’ harbour needed to get extra strength. To create this additional protection, concrete protections block in three different densities are now installed. Each block has a height of 45 centimetres and a density of either 2400, 2800 or 3200 kg/m3. Our customer added the MagnaDense aggregate in the concrete mix to reach the highest density within the specified dimensions.

“Although this was our first experience with MagnaDense, we found it a good aggregate to work with. We are very pleased with the final appearance of the high density Hillblocks,” Barry Eestermans, Purchase Manager for Martens Beton confirmed. He continues, “Also, LKAB Minerals managed to supply us on short notice, which we appreciated.”

High density concrete breakwater blocks

Depending on the wave climate, slope angle, size of the block, and the depth of the sea engineers calculate which density the protection blocks should have. In this particular case, the customer produced three different densities to create the right protection.

Already back in 2001, LKAB Minerals worked together on a research project with Royal Haskoning, Delft University and Deltares to show the benefits of using high density concrete for coastal protection with breakwater blocks. Before and since that time a variety of projects have used MagnaDense for coastal protection and revetment units. Also, we are sure that with the challenges the world is facing, there will be even more projects coming in the future.