Application of ultra-high- performance concrete

Ultra-High- Performance Concrete (UHPC) is a new material that, besides offering high strength, is also very resistant to environmental effects. It is suitable for lightweight structures that are usually prestressed, or for structures and elements exposed to the outdoor environment where it offers excellent durability. In Metrostav, it has been developed since 2010 in the framework of research projects supported by the Ministry of Industry and Trade and the Czech Technology Agency together with TBG Metrostav s.r.o.

In addition to the special composition of cement aggregate and other materials, it is reinforced with a high content of high-strength steel wires that reduce the fragility of the cement matrix. The production technology of construction elements also has its own specific aspects, thus, UHPC has so far been supplied in the form of self-compacting transport concrete. At Metrostav, the company succeeded in realizing the biggest construction from UHPC in the Czech Republic. The project of the suspended footbridge in Čelákovice was modified so that the footbridge has a segmental prestressed bridge deck from UHPC. The pylons and hinges are steel. The footbridge was built between 2013 and 2014 and has the largest span of a suspended concrete structure in the Czech Republic so far (156 m).

The production of segments has been carefully refined, because the relatively complicated shape of the segments has put demands on casting technology. Because there were insufficient normative documents for the proposal, the load-bearing capacity of the individual elements was experimentally verified. Data from research projects has also been used.

The footbridge crosses the Labe River in one field, so a special car was developed for the assembly of segments. The footbridge has received a number of awards, including at the international level. Apart from the footbridges, UHPC applications in other areas are also addressed. One of them is the structure design of a segmented temporary bridge with a board made of hollow panels, which has been experimentally verified.