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Sponsors: ACI Committee 549, Rilem-MCC Editors: Barzin Mobasher and Flávio de Andrade Silva Several state-of-the-art sessions on textile-reinforced concrete/fabric-reinforced cementitious matrix (TRC/FRCM) were organized by ACI Committee 549 in collaboration with RILEM TC MCC during the ACI Fall 2019 Convention in Cincinnati, OH, and the ACI Virtual Technical Presentations in June 2020. The forum provided a unique opportunity to collect information and present knowledge in the field of TRC and FRCM as sustainable construction materials. The term TRC is typically used for new construction applications whereas the term FRCM refers to the repair applications of existing concrete and masonry. Both methods use a textile mesh as reinforcement and a cementitious-based matrix component and, due to high tensile and flexural strength and ductility, can be used to support structural loads. The technical sessions aimed to promote the technology, and document and develop recommendations for testing, design, and analysis, as well as to showcase the key features of these ductile and strong cement composite systems. New methods for characterization of key parameters were presented, and the results were collected towards the development of technical and state-of-the-art papers. Textile types include polymer-based (low and high stiffness), glass, natural, basalt, carbon, steel, and hybrid, whereas the matrix can include cementitious, geopolymers, and lightweight matrix (aggregates). Additives such as short fibers, fillers, and nanomaterials were also considered. The sessions were attended by researchers, designers, students, and participants from the construction and fiber industries. The presence of people with different expertise and from different regions of the world provided a unique opportunity to share knowledge and promote collaborative efforts. The experience of an online technical forum was a success and may be used for future opportunities. The workshop technical sessions chairs sincerely thank the ACI staff for doing a wonderful job in organizing the virtual sessions and ACI TC 549 and Rilem TC MCC for the collaboration.

Carbon reinforced concrete (CRC) is a material composed of a high-performance concrete and a carbon reinforcement (textile grids, lamellas, rods). Composite materials with reinforcements of other fiber materials are called textile reinforced concrete (TRC). The investigations of CRC started more than 20 years ago and the continuous development as well as research findings have opened many fields of application. Today, the use of CRC includes the strengthening of reinforced concrete elements as well as the realization of new elements such as facades, shells and even bridges.

Some of these structures require knowledge of the fatigue behavior due to cyclic loading (e. g. bridges). In a collaborative project of the Institute of Structural Concrete of the RWTH Aachen University and the Institute of Concrete Structures of the TU Dresden, the uniaxial tensile fatigue behavior of two carbon textile reinforcement types was systematically investigated. The specimens were subjected up to 107 loading cycles and stress ranges up to 261 ksi (1,800 MPa). The influence of the maximum load and amplitude were investigated as well as fatigue curves for these two reinforcement types derived.

Textile-reinforced concrete (TRC) combines high-performance fabrics made of impregnated carbon yarns with state-of-the-art high strength concrete. Due to the corrosion resistance of non-metallic reinforcement, the application of TRC for external components especially with freeze-thaw and de-icing salt exposure is promising. This allows for reduction of concrete cover, to create slender structural elements and to execute thin slabs without additional waterproofing or protective decking. Different existing theoretical models and experience from various research projects were used in design of several pedestrian- and road bridges in Germany. The pedestrian bridges in Rems Valley and Ottenhöfen use TRC slabs without shear reinforcement as transversal loadbearing component. For the road bridges in Gaggenau, skew slabs made of TRC with shear reinforcement were chosen as principal structural system. Prior and during construction, experimental investigations on shear capacity were performed at the Institute of Structural Concrete (IMB) of RWTH Aachen. A comprehensive characterization of the material properties of the non-metallic reinforcement is a prerequisite for transfer and adaption of existing design rules, e.g. the determination of tensile strength of the bent portion of pre-formed shear reinforcement. This paper highlights the application potential and further challenges for the use of textilereinforced concrete in new engineering constructions.

In this paper, authors draw information from previous work aiming at contributing to: (i) a summary of the existing knowledge on the mechanical performance of TRM/TRC systems under elevated temperatures and fire conditions; and (ii) highlighting the most important issues of testing procedures and protocols. The paper refers to both TRM- and TRC-related data. The former include experimental assessments of the: (a) TRM-to-substrate residual bond characteristics as a function of temperature; and (b) structural performance of fired masonry elements furnished with a new type of TRM-based overlay for combined structural and energy upgrading. TRC-related data focus on the structural degradation of thin TRC plates under both standard and non-standard fire conditions.

Textile reinforced concrete (TRC) is a great composite material which offers many fields of application. It can be used as a material for the strengthening of existing concrete structures or to build new structures. Possible reinforcement materials are AR-glass, basalt or carbon. The last material named can be referred to as carbon reinforced concrete (CRC). The goal of the project autartec® was to create a floating house which is able to be self-sufficient for at least two weeks. For this purpose, structural elements made of CRC were developed. In this article, a case study of a specific staircase system will be presented. Besides the production of the elements, the paper will also discuss the experimental investigation of the system. On the one hand, the tests were carried out with the boundary conditions of regular use, on the other hand, unfavourable situations were considered. At the end, the complete staircase system will be demonstrated.