South-Eastern Europe’s tallest tower constructed with Glenium SKY 

South-Eastern Europe’s tallest tower constructed with Glenium SKY

Until August 2008, the highest tower of the Balkans, the Avaz Twist Tower, is being built in Sarajevo, the capital of Bosnia and Herzegovina. The tower’s innovative architecture is made possible by Glenium SKY and the customized technical support provided by BASF Construction Chemicals BH.

The Avaz Twist Tower, a new Sarajevo landmark

The structure rises almost 200 meters into the sky, standing out distinctly from all other buildings in the vicinity. Silhouetted against the mountainous landscape, it immediately catches the onlooker's eye. Especially noticeable: The tower seems to be turning around itself. The entire construction is twisted, and thus takes on a very dynamic appearance. It was commissioned by Avaz, Bosnia and Herzegovina's largest newspaper publishing company. After completion of construction in August 2008, the publishing company will move its head office into the Twist Tower.

BASF Construction Chemicals BH has been there from the beginning: Even before construction was begun in 2006, the entire team of six from Sarajevo had been working on the Avaz Twist Tower project together with Hans Günter Hauck, Technology Manager with BASF Construction Polymers in Ludwigshafen. Nevzeta Jarovic, head of BASF Construction Chemicals BH, is the project manager. She is very satisfied with the project's progress: “Our success is based on our high-quality product as well as on the technical support we can offer our customer. We have analyzed the customer's requirements and developed the appropriate technical solutions in cooperation with the constructor. This close cooperation and communication with the customer is part of what makes our services and solutions truly outstanding.” 

Individual solutions through close cooperation

Together with technicians from Vranica, the construction company commissioned for the project, the Construction Chemicals team developed mix options for the concrete. For the intricate construction to take on a particularly airy appearance, a lean architecture with slim cross-beams and thin floor panels is necessary. In order for these elements to still render the tower safe and stable, high-strength concrete was used. 

Glenium SKY 510 was the concrete admixture of choice here: More than 13,000 cubic meters of concrete containing 25 tons of the superplasticizer were used in the Avaz Twist Tower. The use of this concrete admixture ensures high flowability at a low water-cement ratio and results in a high-strength concrete after curing. Good workability and high slump-retention allow for easy transportation of the concrete even to the uppermost floors of the 40-story building. At the same time, Glenium SKY also significantly enhances the service-life of the construction. 
 
Another challenge was posed by the difficult conditions at the building site: Construction takes place in Marijin Dvor, Sarajevo’s city center, and traffic congestions and other problems related to an inner-city location made it difficult to predict transportation times for the concrete. This made the flexible processing time ensured by Glenium SKY even more important. On top of that, the fluctuations in quality of cement, sand and other aggregates needed to be taken into account as well. Still, through cooperation on a daily basis, BASF Construction Chemicals BH and the contractor arrived at solutions to these problems as well. In this way, the team from Bosnia and Herzegovina contributed significantly to the completion of the building shell by August 2007 – well within the customer's tight time schedule.

The construction of the Avaz Twist Tower is one of the most prestigious construction projects in the region, attracting a lot of attention from regional media and the public.
BASF Construction Chemicals expects to be included in the next stage of the Avaz Tower project as well: A second tower with a height of 112 meters is to be built next to the existing one in 2009. The team from Sarajevo is already involved in the planning process. Apart from this, there are plans for a bypass highway near the capital.