International Concrete Abstracts Portal

Carbon Reinforced Concrete (CRC) can be used for new structures and to strengthen existing components. Carbon fibre rods and fabrics are used as reinforcement for new components. Besides CFRP-lamellas, grid-like carbon reinforcements and shotcrete are very suitable for strengthening. Due to the low concrete cover, thin strengthening layers can be realised, which minimise the additional dead load. Depending on the chosen fibre material and impregnation, different failure mechanisms can be observed. The fibre strand should preferably be able to reach the maximum stress under load, but at this stage, the bond behaviour has to be thoroughly considered to prevent failure due to pull-out or delamination. Two carbon reinforcement fabrics are currently being investigated in the research programme C³ - Carbon Concrete Composite.This paper presents the results of large-scale tests on reinforced concrete slabs strengthened with CRC. In addition to the strengthening procedure and the large-scale component tests that have been carried out, this paper deals mainly with the recalculation of the test results and the positional accuracy of the carbon reinforcement and its influence on the flexural strength.

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) 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.

A fundamental challenge for today and the future is the preservation of existing constructions. In addition to repair and maintenance measures, the effective strengthening of existing structures is of central importance to this issue. According to current regulations, a large number of existing reinforced concrete (RC) structures show deficits in their shear capacity, which is often limited by their existing shear reinforcement. The application of thin carbon reinforced concrete (CRC) layers can be a suitable and effective alternative to previously used strengthening methods. In this study, two RC T beam types, which differed in cross-section, were strengthened with CRC. The essential parameters of the strengthening layers were varied, and the influence of these changes on the load-bearing behavior and shear capacity of the T-beams was analyzed. Compared to non-strengthened test specimens, load increases of about 40% were achieved in the CRC-strengthened T beams.

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.