The use of non-metallic, textile reinforcement structures in place of steel reinforcement is a key component in making concrete constructions more sustainable and durable than they currently are. The reason for this is the corrosion resistance of textile reinforcements, which makes it possible to reduce the thickness of the concrete cover and at the same time extend the service life of concrete structures. This reduces the amount of cement required and thus also the emission of the greenhouse gas carbon dioxide (CO₂). By means of textile manufacturing technologies, customized, load-adapted reinforcement topologies can be adjusted to the requirements of highly stressed and well-designed concrete components. The objective of this paper is to give an overview of recent research literature dedicated to textile reinforcement structures that are already used for concrete applications in the construction industry as well as those currently under development. Therefore, textile reinforcement structures, which are divided into one-, two- and three-dimensional topologies, as well as common materials used for textile-reinforced concrete (TRC) are reviewed. Most research has so far been devoted to two-dimensional textile reinforcement structures. Furthermore, novel approaches to the fabrication of textile reinforcement structures for concrete applications based on robotic yarn deposition technologies are addressed.

Textile-reinforced concrete (TRC) is a composite material consisting of a concrete matrix with a high-performance reinforcement made of technical textiles. TRC offers unique mechanical properties for the construction industry, enabling the construction of lightweight, material-minimized structures with high load-bearing potential. In addition, compared with traditional concrete design, TRC offers unique possibilities to realize free-form, double-curved structures. After more than 20 years of research, TRC is increasingly entering the market, with several demonstrator elements and buildings completed and initial commercialization successfully finished. Nevertheless, research into this highly topical area is still ongoing. In this paper, the authors give an overview of the current and future trends in the research and application of textiles in concrete construction applications. These trends include topics such as maximizing the textile utilization rate by improving the mechanical load-bearing performance (e.g., by adapting bond behavior), increasing design freedom by utilizing novel manufacturing methods (e.g., based on robotics), adding further value to textile reinforcements by the integration of additional functions in smart textile solutions (e.g., in textile sensors), and research into increasing the sustainability of TRC (e.g., using recycled fibers).

In carbon-reinforced concrete, the commonly used steel reinforcement is replaced with carbon fiber reinforcement textiles, enabling thin-walled elements by using new construction principles. The high drapability of textiles offers design opportunities for new concrete structures. However, commonly utilized textiles are impregnated with comparatively stiff polymeric materials to ensure load transmission into the textile, limiting drapability. In this paper, a new approach is analyzed: the use of pre-impregnated textiles cured within the concrete matrix. This enables the production of filigree, highly curved components with high mechanical performance, as needed for novel additive manufacturing methods. In the presented trials, rovings were successfully impregnated with potential impregnation materials, cured within the concrete, and compared to rovings cured outside of the concrete. The analysis of the curing process using a rolling ball test determines that all materials have to be placed in concrete 4 to 24 h after impregnation. The results of uniaxial tensile tests on reinforced concrete show that maximum load is increased by up to 87% for rovings cured within concrete (compared to non-impregnated rovings). This load increase was higher for rovings cured outside of concrete (up to 185%), indicating that the concrete environment interferes with the curing process, requiring further analysis and adaptation.

The main advantages of textiles as concrete reinforcement are high corrosion resistance, allowing for thin concrete covers, high drapability, and high strength. Due to these advantages, textiles are particularly suitable as reinforcement for 3D printed concrete, where thin elements and freeform geometries are possible. In this article, a new type of textile reinforcement for the integration into 3D concrete printing is investigated: unidirectional carbon fiber tapes. Carbon fiber tapes are made from carbon fiber rovings by spreading. Three carbon fiber tapes are produced and used as reinforcement in concrete specimens subjected to four‐point bending tests. The results show that for a spreading factor of 2.2 (areal weight 136 g/m²), the flexural strength of the beams is increased by 125% compared to reference beams reinforced with unspread rovings. Further increase of the spreading factor does not increase flexural strength further as the failure mode changes from rupture to spalling.

The aim of this study is to verify the industrial feasibility of integrating textile reinforcement into the 3D concrete printing process and to determine the flexural strength of 3D-printed concrete reinforced with alkali-resistant glass textiles. Due to the non-corrosiveness of the textile reinforcement, thin-walled concrete elements are feasible, reducing material consumption by up to 80 percent compared to steel reinforced concrete. The proposed method of the authors aims to combine 3D concrete printing with a single-sided, movable formwork in order to reduce the time-, personnel-, cost- and material-intensive formwork effort. As a first step towards that goal, in this study, a single-sided stable formwork following the printing path is designed and tested for its applicability on an industrial scale. The prototypical implementation of the printing method through a textile reinforcement is tested. For this purpose, test panels reinforced with textiles vertically and horizontally are printed with concrete. The flexural tensile strength of the printed, reinforced elements is investigated in a four-point bending test. Based on the results of the investigations, the requirements for a movable formwork are defined for the industrial application of this study. The movable formwork will replace the formwork frames in the future, so that the 3D concrete printing process can be optimized in a material-saving way and in terms of circular economy.