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.

The use of technical textiles to reinforce concrete (i.e., textile reinforced concrete [TRC]) extends into entirely new areas of application. The thick concrete covers, as required for steel reinforced concrete, are no longer needed due to the corrosion resistance of textile materials. Slender structural members with thicknesses as small as 10 mm (appr. 4 in.) are possible. Additional characteristic features of textile reinforcement include two-dimensional planar characteristics, as well as ease of deformability and adaptability to complex and curved geometries. This can be exemplified by a pedestrian bridge built of TRC [1, 2, 3]. Various geometric forms, such as slabs, beams, T-beams, shells, and columns can easily be strengthened using TRC [4, 5]. Dimensioning of elements and structures using TRC requires detailed knowledge of the load-bearing behavior of this composite material. Indeed, such behavior resembles that of steel reinforced concrete; however, this behavior is more heavily influenced by the bond between the textile reinforcement and the fine concrete, as well as the bond between filaments within the textile reinforcement [6]. Minimal thicknesses also make it possible to strengthen existing concrete structures using TRC. Such strengthening increases both the ultimate load bearing capacity, as well as the serviceability, of the structure. Experimental results of strengthened slabs and beams, as well as a design model for flexural strengthening, is presented in this paper.

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.

Many regions in Germany show a rising groundwater level. Hence, the load case of buildings concerned changes from non-pressing to pressing water. Residential buildings not designed for the load case of pressing water have to be refitted. Conventional sealing methods are often associated with high complexity and high costs as well as the loss of living space. Furthermore, in many cases, they do not consider the additional static load of pressing water at all. This paper presents a newly developed, subsequently applied sealing against pressing water. It is made of textile-reinforced concrete. Using this composite material, it is possible to produce a sealing system with a wall thickness of about 30 to 35 mm (1.18 to 1.38 in.). During the production of an exhibit wall, it became apparent that the spraying technique is an adequate and practicable method to produce a subsequent sealing of textile reinforced concrete. Initial observations of the wall subjected to hydrostatic pressure reveal the application potential of this construction.

The tensile load carrying behavior under cyclic loading of filaments made of alkali-resistant glass, which is the basic component of the textile reinforcement used for textile reinforced concrete, has been analyzed. Therefore, tensile tests under cyclic loading at four different stress levels were carried out. A damage accumulation, which led in some cases to a failure of the specimens during the cyclic loading, could be observed. This motivated to introduce a strength degradation model. A calibration of the model parameters on the experimental data was performed using an optimization method. A statistical analysis was carried out beforehand, to estimate the initial tensile strengths of the specimens, which were needed for the calibration.