A24 closure: construction work postponed due to concrete cancer”!

A24 closure: construction work postponed due to concrete cancer”!

The A24 motorway in the direction of Hamburg will soon become the scene of construction site activity. Loud NDR The new construction schedule will begin on October 2, 2025 and is expected to last six weeks. During this time, the road will be completely closed on a ten-kilometer section before the Schleswig-Holstein state border and traffic will be routed over the opposite lane.

The reason for these extensive measures is the deterioration in the condition of the concrete pavement, which is caused by the so-called alkali-silica reaction (AKR). This chemical reaction between alkali in the cement and soluble silica in the aggregate results in severe damage to concrete structures and is also known as “concrete cancer”. Roadways and transverse structures that come into contact with water are particularly affected Wikipedia.

A problem of great consequence

The effects of this construction site are a major challenge for many commuters. Traffic situations have worsened, particularly between Mecklenburg-Western Pomerania and Hamburg, as the Berlin-Hamburg railway line has been closed for months and many have switched to cars. The A24, which is already an important connection for commuters, places additional strain on road traffic. A speed limit between Zarrentin and Gallin also makes passage more difficult, which makes the situation even more uncomfortable for commuters.

The AKR doesn't just mean a problem for the A24; In Germany there is a widely estimated need for renovation of 1.2 billion euros for airport runways affected by this response, such as on TUM is to be read. This creates an alkali-silica gel that can break down the concrete from the inside, causing massive long-term damage to the infrastructure.

Measures to avoid damage

To counteract AKR, it is recommended to use cements with a low alkali content and to limit the cement content. In addition, it is crucial to carefully select the aggregates to avoid damage. There have been various construction sites in the past, such as the demolition of the Salmon Weir Bridge in Lübeck, which was damaged due to AKR just two years after its completion.

In order to better understand crack formation in concrete structures, current research projects are going into greater depth. Various hardening conditions are simulated and tested in order to observe the effects of constraint stresses caused by temperature changes and humidity on crack formation. These scientific studies could help to better predict and prevent such damage in the future.

The coming months will be challenging for many commuters and road users. It remains to be hoped that the construction site measures are a necessary evil to ensure the safety and quality of the transport infrastructure in the long term.