Textile-reinforced concrete (TRC) has gained a lot of attraction in recent years. Adequate bond between the phases in this system allows to transfer high loadings, thus enabling high performance. The terminus textile reinforcement, however, comprises many different types of fabrics, which differ in their chemical composition, geometry, surface properties etc., and thus exhibit substantially different bond properties. In the course of RILEM’s Technical Committee 292 work on TRC it was found that a comprehensive understanding of the complex interactions between individual parameters is still lacking. This is amplified by the fact that different types of textile reinforcement are preferably used in different regions of the world. This paper therefore attempts to compile findings from literature on the bond in TRC. The database used was created in the course of the TC work. Additional papers of relevance were identified by scanning scientific web databases. The different influencing parameters are given in this paper in a hierarchical order, starting from the level of the individual constituents (filament and matrix) to impregnated fabrics and the influence of textile manufacturing and architecture on the bond. Finally, by mapping all the cited literature used in this paper based on grouped keywords the complex intercorrelations are visualised.

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).

One major challenge preventing widespread introduction of digital concrete production is the integration of reinforcing materials. Textile grid structures offer a possible solution for this challenge. Textile reinforced concrete (TRC) has been researched for approximately 20 years and is currently being commercialized, initially in pre-cast elements for facades and bridges. TRC enables the construction of thin-walled, strong structures with a high freedom of design, properties well suited for the integration in digital concrete production. First trials for this integration have been performed and published. However, these studies only use short fibres mixed into the concrete matrix or textile reinforcement within the printing plane, which limits the transferred loads. This study shows the results of preliminary tests of vertical, out-of-plane textile reinforcements for digital concrete production. The textile reinforcement is fixed vertically and the concrete printing process is performed diagonally, “through” the textile. The results of four-point bending tests are presented.

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.