High-spec screed for supply tunnels

Berlin - Germany

The floors of some of the supply tunnels serving the Virchow Hospital Campus of Charité Berlin were in need of rehabilitation. Thanks to optimally matched MC products, a load-bearing screed with high surface hardness was installed within just two weeks.
The buildings on the campus are connected via underground supply tunnels through which medical equipment, food, etc. are conveyed by industrial truck. The wear and tear caused on the tunnel floors through usage over a good 20 years was such that portions of them had to be completely refurbished. The Charité administration commissioned the Berlin-based company Bahnsch GmbH as general contractor to carry out the work. Bahnsch worked in close cooperation with MC area manager Steffen Sünboldt and master screed layer Mike Köhnke in determining the structure of the screed system. The screed-laying firm selected to perform the installation work was SOKO Fussboden GmbH of Elmenhorst/ Lichtenhagen in the province of Mecklenburg-Vorpommern.

Tunnel floors completely rehabilitated

Initially, a section of about 500 m² of the underground supply tunnels was to be replaced. The client required a bonded screed between six and 12 centimetres thick with a strength of > 40 N/mm², which was to be released ready for full-load transport operations as quickly as possible. 
First, the old screed was removed down to the load-bearing concrete. The remaining substrate was then prepared for the new floor system by shot-blasting. Because the substrate was not particularly absorbent and needed a good bond, MC-Estripox pro – a product characterised by particularly good adhesion to mineral substrates – was chosen as primer and bond coat in one.

Screed-laying in a supply tunnel of the Virchow Hospital Campus of Charité Berlin
Screed-laying in a supply tunnel of the Virchow Hospital Campus of Charité Berlin
© MC-Bauchemie 2020


The ideal solution: MC’s rapid-set cement

The screed was then laid on top using the fresh-in-fresh technique. Due to its low shrinkage behaviour, MC-Floor TurboCem was used to achieve the required layer thickness and strength. This fast-setting cement combines long working times with very rapid strength development. Graded CT-C50-F7 according to EN 13813, MC-Floor TurboCem has higher compressive and flexural strength values than standard screeds. It is installed earth-moist, can be walked over after only four to six hours, and after just 24 hours exhibits a compressive strength of > 20 N/mm² and a residual moisture content of < 3 %. Just one week later the carbon-fibre-reinforced, mechanically highly resistant MC-Floor Connect ST joint profiles were installed.
Exceptional appearance and protection with MC-Estrifan Color Protect pro

The entire screed was then primed with MC-DUR 1177 WV-A. The two-component, water-dispersed epoxy resin is the ideal bond coat between screed and sealant and can also be used on matt-damp mineral substrates. The top seal was applied in two layers using MC-Estrifan Color Protect pro.

abs 123 abs 123 abs 123 abs 123 abs 123 abs 123 abs 123