Despite intensive research on material properties of non-metallic technical textiles for internal reinforcement in concrete, the long-term durability is not yet fully understood. In this work, results of preloaded long-term durability tensile tests on carbon-reinforced concrete specimens under environmental factors of stress, temperature, moisture and alkalinity are presented. Based on investigations of non-metallic glass fiber reinforcements with polymer matrices, where strength losses occur over time, it was planned to derive a time to failure curve and to determine a reduction factor for the tensile strength of the carbon textile reinforcement. However, no loss of strength was discovered in residual capacity tests due to the high material resistance and therefore no reduction factor due to the environmental factors could be derived. After more than 5000 h of testing, the residual capacity tests showed an increase in the ultimate failure stress in comparison with the short-term tests. In addition to the long term-durability tests, the influence of the preloading was investigated. The preload was applied to the long-term tests and led to a straighter alignment and loading of the filaments and thus to an increase in the ultimate capacity.

New materials allow new building designs and construction types. However, initial construction projects using the new materials show that traditional construction principles ‐ in the case of carbon reinforced concrete those derived from steel reinforced concrete ‐ are still being used. In other words, conventional materials are merely substituted. Only combined with intelligent construction strategies it is possible to exploit the full potential of innovative materials. Detached from established patterns of thought, the fundamentals for a new way of building with concrete are to be created in the frame of the Collaborative Research Centre Transregio (CRC/TRR) 280 project “Design Strategies for Material‐Minimised Carbon Reinforced Concrete Structures–Principles of a New Approach to Construction” at Technische Universität Dresden (TUD) and RWTH Aachen University. These are to be based on profound insights into the mechanical behavior of novel mineral structures. Innovative lightweight construction strategies and material composites reduce resource and energy consumption while maintaining high levels of usability, structural safety, and durability, while the aspirational esthetics make a valuable contribution to the culture of building. The long‐term research alliance of TUD and RWTH pools the excellent competencies, inspiring research into material‐minimized construction with mineral composites. The article highlights the research activities planned for the first period from July 2020 to June 2024.

With the innovative composite material carbon-reinforced concrete, thin-walled, high-performance components can be realized. A combination of carbon fiber reinforced polymer (CFRP) bars and non-metallic textile grids is advantageous as it exploits the full potential of the high-performance materials to reduce dead loads, increases durability, and extends lifespan. For new components with such mixed reinforcement, applicable design concepts and engineering rules are necessary to accurately determine the structural and deformation behavior. To validate models and detailing rules previously developed, three large carbon reinforced concrete I-beams were designed and tested to failure with a realistic line load. CFRP bars served as principal bending reinforcement, whereas shear and flange reinforcement consisted of textile grids. Results showed that existing models for bending using variation of strain distribution as well as non-linear finite-element analysis predicted the flexural behavior of structural components with mixed reinforcement in ultimate limit state (ULS) appropriately. Yet, calculation of shear capacity requires further studies to determine textile reinforcement contribution and estimate reduction for concrete strength in reinforced compression struts. For serviceability limit state (SLS), three methods for determination of deflection delivered good results. In future, a rethinking is required with regard to the ductility and robustness of CFRP-reinforced concrete components. In this respect, pronounced cracking as well as the large ultimate strain and deflection compensate for the lacking yield capacity of the reinforcement.