Frank Jesse

Flexural Strengthening of RC Structures with Textile-Reinforced Concrete

Textile-reinforced concrete (TRC) is a high-performance composite in which technical textiles made of high-performance fibers are embedded in a fine-grained concrete matrix. Textile-reinforced concrete extends concrete applications to completely new fields. Besides slender new concrete elements, strengthening of already-existing concrete structures by thin textile-reinforced concrete layers is possible. This type of strengthening noticeably increases both the ultimate load-bearing capacity and serviceability of reinforced concrete structures. This aspect is shown in the present paper using experimental results of TRC-strengthened slabs.

Load-Bearing Behavior of Textile-Reinforced Concrete

Textile-reinforced concrete (TRC) is a rather new high-performance cementitious composite material. In TRC composites, yarns or rovings from high-performance fibers, such as AR glass and carbon, are processed and oriented in a planar structure. This enables an optimal alignment and arrangement of fibers within structural members and allows for the production of extremely thin concrete components with a high load capacity. This paper gives an overview of some of the most relevant material properties of TRC and the associated mechanisms influencing the mechanical performance of TRC composites.

Strengthening of a Barrel-Shaped Roof using Textile Reinforced Concrete

When reconstructing the Zwickau School of Engineering for use as an IRS Office it became necessary to strengthen a reinforced concrete roof structure more than 100-years of age with textile reinforced concrete (TRC). Compared to other strengthening options, only TRC was able to meet the varied demands of monument and fire protection, the architect, as well as the construction company/contractor, while simultaneously meeting all static standards. The thin TRC layer, made of fine-grained concrete with embedded textile reinforcement, was applied to the roof structure in a total thickness of only 10 to 15 mm.

Textile-Reinforced Concrete for Flexural Strengthening of RC-Structures—Part 1: Structural Behavior and Design Model

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. Various geometric forms, such as slabs, beams, T-beams, shells, and columns can easily be strengthened using TRC. 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. 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.

Efficiency of Multi Filament Reinforcement in Cementitious Composites

The use of continuous fiber reinforcement in a cementitious composite is very efficient concerning strength and ductility. Using technical textiles made of AR-Glass or Carbon in a cementitious matrix leads to textile reinforced concrete and is a way of doing this cost-effectively. In an extensive study, mechanical testing was combined with microscopic observations to identify basic mechanisms of load transfer between multi- filament yarns and matrix. Uniaxial tension tests on the composite were carried out to evaluate mechanical performance of textile reinforced concrete reinforced with different types of fabrics. Thin section petrography was used to find specific bond properties. The paper discusses failure mechanisms of textile reinforced concrete and how they are influenced by different micromechanical bond parameters. It has been found that bond characteristics between single filaments in the roving structure and between filaments and matrix and how they are distributed across the filament bundles and along the fiber-matrix interface are of major importance for composite performance. Bond properties are affected by several parameters during textile processing, for instance yarn material, yarn titter, size, weaving pattern, and others. Understanding these dependencies leads to recommendations for optimizing textile reinforcement.