Sustainable dike reinforcement projects 

For dike reinforcement, steel sheet pile walls are widely used to protect the dike against the failure mechanisms macrostability and piping. The sheet piling supports the soil dike under normative loads. Especially at locations with limited space, a sheet pile wall is the ideal reinforcement of the dike. Especially interesting are locations where both stability and piping are normative. A single sheet pile wall construction can then be used to tackle both reinforcement tasks. 

The amount of steel sheet piles required in a project affects the sustainability of the project. ArcelorMittal reduces the environmental impact of the steel sheet piles delivered by focusing on three areas: Recycle, Reduce & Reuse. 

Recycle

The steel for the sheet piles, produced in Luxembourg, comes from an electric arc furnace, which can run on 100% of green electricity. An electric arc furnace uses approximately 100% of steel scrap, no more iron ore is involved. This eliminates the extraction of primary raw materials from nature and produces less waste compared to the blast furnace process, where carbon dioxide emissions are about a factor of 5 to 6 higher. Per ton of steel sheet piling, the electric arc furnace production process releases 360 kg of CO2. These emissions are demonstrated through the Environment Product Declaration (EPD) EcoSheetPiles™ Plus, drawn up specifically for the Dutch market. This puts ArcelorMittal in a unique position among steel sheet pile producers because of its short distance to the plant and sustainable production process. 

Dike reinforcements often have a design life of 100 years. Because corrosion of sheet piles in a dike body is minimal, the sheet pile will be removable from the dike even after 100 years. Some of the removed sheet piles may be reused in other projects. Anything that cannot be reused is fully recycled so that it goes back into the electric arc furnace as a raw material. The circle from scrap metal - to steel sheet piling - to scrap metal is now complete and repeated in the next project. 

Reduce 

The other major saving in emissions, and thus increasing sustainability, comes from reducing the amount of material required. The conclusions of the reports from the 2018 sheet pile collapse test in Eemdijk show that it is possible to design sheet piles shorter and lighter in dike reinforcements. Further optimization possibilities include the application of higher steel grades (up to S460 GP), staggering of sheet piles (alternating shorter and longer lengths), application of sheet pile panels (with openings of up to 1 meter), and tailored deformation testing by allowing locally larger displacements. 

Reuse 

Steel sheet piles are excellent reusable for temporary applications, for example in temporary construction pits. In permanent constructions, such as dike reinforcement, used sheet pile walls are not often applied yet. At locations where the failure mechanism piping plays a role, demand is now arising for the application of used sheet pile walls. To protect the dike from piping, the seepage path must be extended or interrupted. Because the sheet piling is not loaded for strength, a used sheet piling can perform this function just as well as a newly produced sheet piling. The big difference is that the entire emissions from the production phase do not have to be included for the used sheet pile; they are already partially included in the previous temporary applications. 

So with steel sheet piles, many combinations are possible to create the most sustainable solution within a project.