Simulationsbasierte Optimierung von Stahlfaserbeton

In a collaboration project between the Fraunhofer Institute for Building Physics (IBP) and the Fraunhofer Institute for Industrial Mathematics (ITWM), a computer-based simulation of the orientation of steel fibers was developed based on the flow processes that occur during casting the concrete into a form. At the start of the investigations, the variable shear stress of different paste, mortar and concrete mixes was measured. From the resulting measured values, absolute values for the shear-rate dependent viscosity, the yield point and the thixotropic properties of the materials were determined. For the simulation, an exemplary experimental setup was chosen where the concrete flows into a form. To validate the results, CT images of the specimens cast in the laboratory were made. It could be observed that the steel fibers, when flowing around the cylindrical body in the experimental setup, arrange themselves in nearly circular pattern around this body. After this obstacl e, two parallel running flow fronts could be observed.