Trade Journals for the Concrete Industry

This article presents an extrusion process for very stiff steel fibre-reinforced concretes (FRC), which can be used to align fibres almost exclusively in a single direction. For this purpose, a special alignment unit was developed and prototypically implemented. The alignment approach is particularly suitable for quality-assured prefabrication, aiming at exact fibre orientation along load-dependent tensile stress trajectories. Conventional concrete placement methods lead to a high variability in the fibre orientation, mainly due to the size and shape of the formwork as well as the compaction of the fresh concrete, which significantly reduces the fibre performance for the desired tensile direc- tion. In the first applications on real-scale panels, the extru- sion method was able to double the load-bearing capacity, which was further achieved with a comparatively low scat- ter in test results. Extrusion is particularly suitable for the precast industry, facilitating optimized use of materials.