A24 Blankenburgverbinding

The A24 Blankenburgverbinding at a glance

The newly constructed A24 is a four-kilometer-long series of technical structures. We start at the A20 in Vlaardingen, where a sunken junction has been constructed. This sunken section runs southward and ends in a land tunnel. We then pass two viaducts and a flood barrier before arriving at the technical highlight: a sunken tunnel under the Scheur river that connects to an above-ground junction with the A15 in Rozenburg. In other words, it is a unique project that brings together all disciplines of infrastructure engineering.

A land tunnel with reinforced underwater concrete

The Holland Tunnel is a jack of all trades: it blends in completely with its surroundings and provides knowledge for other parts of the project. Reinforced underwater concrete was used to meet environmental requirements. This special construction technique led to less material being used and a reduction in CO₂ emissions. The tunnel was constructed at a lower level and the original grassland was restored on the roof. This technical structure was the first to be completed, which provided an opportunity to conduct tests and utilize the experience gained in the construction of the Maasdelta Tunnel.

Immersed tunnel operations in the heart of the world's busiest shipping channel

The biggest challenge within the project was sinking two tunnel elements that together form the Maasdelta Tunnel. To this end, the access roads to the tunnel were built on the north and south banks. Two tunnel elements measuring 200 meters long, 42 meters wide, and 8 meters high were constructed in a dry dock near Rozenburg. After being floated and transported, the elements were sunk to a depth of 27 meters. The access roads were then connected to the tunnel elements and the tunnel was completed. The result: a 945-meter tunnel that has been carrying traffic between Rozenburg and Vlaardingen since December 2024.

A long-standing relationship with stakeholders

Good environmental management is the basis for a project of this size. Together with Rijkswaterstaat, we invested in clear communication with local residents, government agencies, social organizations, and the business community. We held substantive discussions, remained in dialogue with each other, and communicated about the work in a timely and transparent manner. One of the tools we use for this is BIM. This allows us to provide all parties with insight into how the project is progressing and what it will ultimately look like.

Regular maintenance

Regular maintenance started in 2025. Throughout the year, there are nightly closures for inspections, cleaning of tunnels and installations, green space management, and minor asphalt repairs. Road users are informed in a timely manner via digital signs and detour routes. Ballast Nedam carries out the maintenance via BAAK. This maintenance contributes to a safe and reliable infrastructure.