View inside the tunnel.

Innovative coating system protects Berlin motorway tunnel

MC's MC-Color T 21 shields Berlin's Grenzallee tunnel for A100 expansion and ensures durable protection, meeting safety standards for the traffic artery.

MC-Color T 21 system used for A100 motorway tunnel

Germany

As part of the expansion of the A100 motorway in Berlin, the walls of the new Grenzallee tunnel received MC’s latest protective coating MC-Color T 21. As the motorway is one of the most important traffic arteries serving the city, a particularly safe and durable solution was required. With Nafufill R3 FM and MC-Color T 21, a proven coating system from MC, the tunnel walls are now permanently protected.

 

 

German motorway A100, also known as the Berlin ring road, connects numerous districts of the German capital. It runs right through Berlin and serves as a link to other motorways and major roads. The A100 motorway consists of two sections known as the eastern and western ring. The eastern ring runs through the districts of Friedrichshain, Kreuzberg and Neukölln, while the western ring links districts such as Charlottenburg and Tempelhof.

Berlin ring road – key to the city's transport flows

With a total length of 20.9 km, the Berlin ring road is one of the city’s most important traffic arteries, enabling road users to quickly and easily bypass the city centre. The Berlin motorway is currently being extended between the Neukölln junction and the Treptower Park junction. It is connected to the urban traffic network via three exits and includes the 385 m long Grenzallee tunnel.

Innovative OS 4 coating system for road tunnels

To protect the inner shell of the Grenzallee tunnel, the BAB A100 consortium consisting of Max Bögl Bauservice GmbH & Co. KG and HOCHTIEF Infrastructure GmbH, together with the application contractor DMI Injektionstechnik GmbH from Berlin, decided in favour of an innovative OS 4 coating system from MC. This involved a combination of the new polymer-modified fine mortar Nafufill R3 FM and the high-performance coating MC-Color T 21. The work started in March 2023, after the coating system had already been successfully tested on a trial area a year earlier. Since then, around 8,000 m² of the tunnel’s wall surfaces have been duly coated with the protective system.

The fine mortar Nafufill R3 FM is applied manually with a steel trowel for levelling.

The fine mortar Nafufill R3 FM is applied manually with a steel trowel for levelling.
© MC-Bauchemie 2025

The high-performance coating MC-Color T 21 was applied using the airless spraying method.

The high-performance coating MC-Color T 21 was applied using the airless spraying method.
© MC-Bauchemie 2025

Durable surface protection of the tunnel’s inner shells

After the substrate had been prepared for coating by high-pressure water blasting, it was levelled with the curing-free fine mortar Nafufill R3 FM. It fulfils all the requirements of performance class R3 in accordance with EN 1504-3. As there was no need for time-consuming curing after application, this significantly reduced the amount of work required on site. In the next stage, the ready-to-use surface protection MC-Color T 21 was applied using the airless spray method. MC-Color T 21 is a high-performance coating with exceptional reflective and dirt-repellent properties. It is a tough, weather-resistant coating with fast curing and overcoating times, which makes it an exceptional fit for traffic structures. These properties also make it suitable for application in road tunnels and it has been tested and approved in accordance with the national codes ÖBV, ASTRA and ZTV-ING Part 7.

 

Finally, the transparent anti-graffiti system MC-Color Proof vision was applied to the cornices of the tunnel entrance areas above the tunnel tubes. This serves as additional protection against graffiti for the coat of arms of the city of Berlin, which will adorn the entrance to the tunnel. As things stand, the A100 tunnel with MC’s protective coating system is scheduled to be opened to traffic at the end of 2024.

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