Bemessung von Tübbingen mit Basaltbewehrung

For the majority of concrete structures in Austria, as well as abroad, conventional steel reinforcement is used despite numerous disadvantages. Firstly, it is highly sensitive to corrosion, which leads to costly maintenance and repair work, and secondly, its energy intensive production and the associated CO2 balance are increasingly coming under ecological critics. For these reasons, among others, alternative reinforcement materials are gaining importance, opening up promising opportunities from both a technical and an ecological perspective. The use of basalt fibres, which are extracted from basalt rock available worldwide and processed into reinforcing bars or rovings, has proven to be especially sustainable. Basalt is resistant to corrosion, offers high tensile strength, and, in the case of rovings, enables an automated manufacturing process with flexible reinforcement adjustment. Despite these advantages, the widespread use of basalt reinforcement is hindered by several factors. In addition to high production costs, the main obstacles are the lack of standardized testing methods and design bases, which makes it difficult to compare material parameters and integrate them directly into common design programs. This is where this thesis comes in, analyzing the potential but also the existing challenges of basalt reinforcement, researching normative principles and experimentally determining essential material properties in order to create a basis for a design concept. Experimental, analytical and numerical studies were combined for this purpose. The numerical calculation methods were performed using the finite element program Sofistik. In addition to direct tensile tests, the series of small-scale tests included a large number of bending tests with conventional steel reinforcement as well as basalt reinforcement with bars, rovings and GeoGrids. Based on the results achieved, the numerical model was adapted and the load-bearing behavior of the reinforcement was determined iteratively. In addition, a model was created in Sofistik for a large-scale segment test, which represents various load cases relevant to practical application, including those in the segment test facility as well as rock pressures and the thrust force of the tunnel boring machine, and also provides an outlook on the behavior of the segment in the serviceability limit state with a crack widths limitation. The results show that basalt reinforcement, depending on the manufacturer, diameter and arrangement, achieves significant tensile strengths, which can also be proven in the calculations. This work provides a better understanding of the potential of basalt as a reinforcement material and shall lay the groundwork for future applications.