HeidelbergCement has stated that ultra-high strength fibre-reinforced concrete (UHPC) opens up new possibilities and fields of application in construction. The use of UHPC has enabled the construction of a railway bridge over the Dürnbach, Gmund, within a few days.
The concrete’s optimised grain composition makes it possible to achieve a dense microstructure, high strength, and excellent durability properties. Its strength is usually more than 150 MPa - three or five times higher than conventional concretes that are currently used in bridge construction. It is also characterised by high chemical resistance and mechanical strength. The addition of micro steel fibres for reinforcement has the result of high tensile strength, as well as making it more ductile.
UHPC was thus used as a solution for the a small but complex, future-orientated building task that was conceived by the Department of Solid Construction of the Technical University of Munich (TUM), together with the engineering office Büchting + Streit in Munich.
For the superstructure renewal at Dürnbach, regulations for the application of UHPC were defined by the TUM with an expert’s opinion. In particular, this used a current draft of the new German Committee for Reinforced Concrete (DAfStb) guidelines for ultra-high strength concrete, and was supplemented by the additional application of rules based on the company’s own research results and laboratory experience, as well as international regulations. With the current guidelines of the DAfStb being drafted, a sound basis for the broader application of UHPC in German construction will be available for future applications.
“The concrete technology concept was provided by HeidelbergCement,” said Lisa Wachter, Project Engineer in the Engineering and Innovation Department at HeidelbergCement in Leimen. “It was fortunate that we were just planning the launch of our UHPC, which was well-suited to the planners’ specific requirements. Based on our compound, we have developed the recipe for self-compacting coarse-grained concrete of strength class C150/155 and adjusted it onsite in the precast plant. The powdered UHPC compound Effix PLUS is made of high-quality cement, additives, rock flour, and sands, with a very finely graded grading curve. A double shaft mixer with a plasticiser was used and there is much less water than is usual for ‘normal’ concrete.”
Read the article online at: https://www.worldcement.com/europe-cis/08022019/heidelbergcement-uses-uhpc-for-superstructure-renewal/