Almost 60 years ago, the recently constructed Henninger-Turm (Henninger Tower) – the grain storage silo of a brewery in the Sachsenhausen district of Frankfurt – became a major landmark and a symbol of Frankfurt almost overnight. It was to be replaced by a new tower which was to house flats and offices instead of gain, at the same time as maintaining its function as a symbol. The concrete for the new building was optimized using concrete admixtures from Master Builders Solutions.
At the end of the 1950s, Henninger-Bräu AG built one of the world’s tallest grain storage silos in Frankfurt am Main, the Henninger Tower, which soon became a symbol of the banking metropolis on the River Main. Apart from its main function is a storage silo, the building, which was almost 120 metres high, housed a tavern in the lower section and one, later even two rotating restaurants and an observation deck in the barrel-shaped tip of the tower. However, the building was closed to visitors from 2002 onwards for fire safety reasons and the traditional cycle race “Rund um den Henninger-Turm” (around the Henninger Tower) changed its route and its name in 2008.
Demolition work finally started in 2013 and the old building was to make way for a new residential development.
New tower in the old shape
The design by Frankfurt architects Meixner Schlüter Wendt takes up the iconic shape of the landmark: the tower was to accommodate 206 flats and office units and a modern version of the tip, with straight lines, was to house a rotating restaurant and an observation deck with public access. The tower complex, with an overall height of about 140 metres, also includes a U-shaped six-storey building surrounding the bottom of the tower like a courtyard.
The object of the design was to produce a silhouette which was at least similar to the old tower as part of the Frankfurt skyline.
Requirements for concrete: flowing properties and consistency extension
500 cubic metres of high-strength C 80/95 concrete were to be supplied for the project. Despite a low water/cement ratio, the concrete needed to have good flowing properties and to maintain its consistency over a longer period of time. The solution adopted was to combine two concrete admixtures. MasterGlenium ACE 460 was added to ensure good flowing properties, combined with MasterSure 900 as a consistency extender.
MasterGlenium ACE is a superplasticizer based on modified polycarboxylate ether which has a very high superplasticizing effect with low dosage. With its outstanding dispersing effect, this product can be used flexibly and is especially well-suited for the production of high-strength and other special concretes.
MasterSure 900 is also based on modified polycarboxylate ether: the specific modification allows unprecedented flexibility in extending the consistency of concrete.
Combination of flexibility, safety and convenience
In combination, the two additives allow optimum control of consistency even under difficult conditions. The system, therefore, offers a high degree of flexibility, safety and convenience for ready-mixed concrete producers.
On this project, the addition of MasterSure 900 reduced the consistency loss to five centimetres in an hour. This meant that the high-strength concrete could be delivered to the site without any problems, allowing a generous time window for careful concreting.
/in%20USE/partner_Master_Builders_Solutions_service_customer_benefits.jpg)