Trade Journals for the Concrete Industry

Ultra high performance concrete (UHPC) represents the current state of the art of concrete technology. Although the compressive strength of UHPC is of the same order of magnitude as that of structural steel (approx. 200 MPa), its tensile strength remains relatively low at only 7-10 N/mm2. The replacement of steel by UHPC at the material level is thus impossible. New ideas for designs and building methods are to be developed for a meaningful and broad application of UHPC. The optimisation of known cross-sections alone will certainly not lead to the desired goals, as past experience has shown. The fact that the demands on the manufacturing and processing of UHPC are very high due to its high sensitivity to fluctuations in the raw materials and the manufacturing processes must also be taken into account. UHPC is thus much more suitable for the precast industry than for the in-situ construction method, although several such pilot projects have also been successfully completed. Furthermore, it should be emphasised that the use of delicate structural elements permits smaller tolerances. Deviations of the order of centimetres, which commonly occur in the concrete construction method, can no longer be accepted here. This also speaks for the use of precast parts. Means of connection that are suitable for the material play a decisive role in the joining of industrially manufactured elements to form desired constructions, i.e. the modular construction method. Past experience has shown that the dry joint, utilising the prestressing force, is a suitable method of connection for UHPC constructions [4]. On the one hand it allows the high compressive strength of the UHPC to be exploited and, on the other, disassembly for further use is possible. This brings us closer to the goal of sustainable building.