The first practical application of the innovative strengthening method using textile reinforced concrete was carried out in October/November 2006 in the retrofit of a reinforced-concrete roof shell structure at the Univer-sity of Applied Sciences in Schweinfurt, Germany. Since textilereinforced concrete had not yet been standardized as a construction material, a single “special-case” technical approval was sought from and granted by the appropriate authorities for this particular application of textile reinforced concrete. This strengthening method entailed the layer-by-layer application of three layers of fine-grained concrete and textile fabric comprising 800 tex carbon rovings onto a rough, sandblasted concrete surface. The resulting strengthening layer has a thickness of only 15 mm (0.6 in.) and extended the roof structure’s service life.

Nowadays, thin-walled load bearing structures can be realized using textile-reinforced concrete (Brameshuber and RILEM TC 201-TRC, 2006). The required tensile strength is achieved by embedding several layers of textile. By means of the laminating technique the number of textile layers that can be included into the concrete could be increased. To further increase the first crack strength and the ductility and to optimize the crack development, fine-grained concrete mixtures with short fibers can be used. By simultaneously using different types of short fibers, the positive properties of each fiber may be combined. By a schematic stress-strain curve, the demands on short-fiber mixtures are defined. Within the scope of this study, short fibers made of glass, carbon, aramid, and polyvinyl alcohol are investigated in terms of their ability to fit these requirements. Furthermore, examinations to determine the fiber types and fiber volumes are presented. Finally, two hybrid fiber-reinforced concretes are introduced. On the basis of stress-strain curves of textile-reinforced concrete, the advantages of these fiber mixtures are discussed.

At present there is a rising interest of architects and engineers in the application of textile-reinforced concrete (TRC) as a construction material. Filigree, self-supporting and ventilated façade systems are state of the art in the application of TRC. In current investigations, potentials for lightweight structural members are developed. The required models for a secure design of structural members are deduced within the framework of the research activities in the collaborative research center 532 at RWTH Aachen University [1]. The article outlines fundamental research results as well as their realization in first applications.

Textile-reinforced concrete (TRC) is a composite material made of open-meshed textile structures and a fine-grained concrete. The application of TRC leads to the design of filigree and lightweight concrete structures with high durability and high quality surfaces. In recent years, TRC has become an attractive choice for the production of ventilated façade systems. To attain the goal of a lightweight façade with large spans and without bracing stud-frame-systems, sandwich panels with two thin TRC-facings and a core of rigid polyurethane foam have been developed at RWTH Aachen University. Within a compact section, this slender building envelope provides a capable load-bearing behavior, superior heat insulation and fire resistance as well as a sufficient sound insulation. In the paper, the investigated production methods, the test results of sandwich members loaded by bending and shear forces, tests on sound insulation and fire resistance, as well as the deduced calculation models are presented.

The main advantage of textiles as reinforcements in cement-based composites is in the enhancement of mechanical behavior. Textile-reinforced concrete (TRC) has emerged as a novel composite with various potential applications in non-structural and, more recently, structural building materials, including thin and slender elements, repair, and strengthening of existing structural members. The wide variety of textile production methods allows great flexibility in textile design, which enables controlling of textile geometry, yarn geometry, and orientation of yarns in various directions. This diversity is advantageous in the development of cement-based composites and allows engineering of the performance of the final products for the desired requirements. Recognizing the increasing research interest in thin fiber-reinforced cement-based composites using fabrics and hybrid systems (fabrics + chopped fibers) and their emerging industrial applications in the last years, there has been a close communication and collaboration between ACI Committee 549, Thin Reinforced Cementitious Products and Ferrocement, and RILEM TC 201, Textile Reinforced Concrete (TRC), in the area of TRC. Following two two-part technical sessions, held at the 2005 ACI conventions in New York and Kansas City, ACI Committee 549 sponsored the technical session “Design and Applications of Textile Reinforced Concrete” at the ACI Fall 2007 Convention in Puerto Rico. Seven papers were presented by invited international experts from Germany and co-authored by members of RILEM TC 201. This Special Publication (SP) contains seven papers that provide insight into the state-of-the-art design and application of TRC. The topics of the papers cover the following: materials aspects related to serviceability; strength and damage accumulation; TRC for flexural strengthening of reinforced concrete structures – structural behavior, design model, and application for a concrete shell; use of TRC as a subsequently applied waterproof structure; application of TRC for lightweight structures; and sandwich panels with thin-walled TRC facings for structural exterior walls and nonstructural façades. The papers included in this publication have been peer reviewed by international experts in the field according to the guidelines established by the American Concrete Institute. The future of thin fiber and textile-reinforced cementitious systems depends on their ability to compete with existing solutions and to identify new applications. Efforts are required in the areas of process, design, and implementation in industrial and full-scale applications of TRC. On behalf of ACI Committee 549, the editor would like to thank all the authors for their contributions and the reviewers for their assistance and valuable suggestions and comments.