Basic investigations on the robot-aided magnetic distribution and alignment of microsteel fibers in thin-walled UHPFRC components

• Applicant: Professor Dr.-Ing. Harald Kloft
• Subject Area: Structural Engineering, Building Informatics and Construction Operation
• Term: from 2018 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 408043955

The aim of the proposed research project is to explore the basis for the manufacturing process of resource-efficient components by means of the controlled, robot-based magnetic distribution and orientation of steel fibers in UHPFRC (Ultra-High Performance Fibre-Reinforced Concrete). The proposed research project is based on the possibilities offered by digital and robot-supported component manufacturing on the one hand and the potential of fiber alignment to increase the material efficiency of UHPFRC on the other. The method of distributing and orienting steel fibers in UHPFRC is based on the physical phenomenon of magnetism. Since steel fibers are ferromagnetic, magnetic fields can selectively modify their position in fresh concrete. The aim of the research project is to align the position of the steel fibers in the concrete matrix during the production process according to the force flow and the maxim “form follows force”. This defined arrangement of the fibers in a component is intended to significantly increase the effectiveness of the fiber component used and, in addition to improved workability, lead to a considerable reduction in the fibers used, as a result of which a great potential for savings in ecological and economic resources is provided. The reproducible control of the process, which is ensured by the use of the latest developments in the field of robotic production, will be decisive for an economic, building-practical application of the method. The results of the first work packages should, if possible, be integrated into the sub-project of the DFG's Priority Program 1542 "Light Construction with Concrete", which runs until the end of 2017 at the ITE and iBMB. In particular, the method could be used in the production of modularly constructed rod and surface elements (plates) as well as in the highly stressed joint sites (tooth connections) with the aim of achieving a clear increase in performance of these high-performance components. The fiber alignment represents one of several aligned processing steps for the production of a component in a prospective digital manufacturing chain. The practical applications for this method of magnetic fiber alignment are manifold and conceivable for different component groups. Thus, the fiber content in the case of large-area components, e.g. industrial flooring, can be significantly reduced by a defined fiber orientation. Further, the method can be used to increase the tensile strength in locally highly stressed areas, e.g. in the component joining areas or for the gradation of material properties across the structural thickness. In addition, the research project aims at the area-specific replacement of conventional reinforcement, such as the thrust reinforcement in double T-beams or hollow beams made of UHPFRC.

• DFG Programme: Research Grants