JEC COMPOSITES MAGAZINE - Issue #44 - October 2008 - Special Asia - 32

FEATURE “Reinforcement” Textile-reinforced concrete with high-performance carbon fibre grids The need to strengthen and retrofit existing concrete structures will increase dramatically in the near future. Textile-reinforced concrete will open new opportunities by offering higher performance, better handling in use and lower overall cost. BERNHARD PLAGGENBORG, SALES ENGINEER, COMPOSITE MATERIALS, SGL TECHNOLOGIES GMBH SILVIO WEILAND, CONSULTANT AND PROJECT MANAGER, DEUTSCHES ZENTRUM TEXTILBETON (GERMAN CENTRE FOR TEXTILE REINFORCED CONCRETE) amount of reinforcement fibres to reach an equal load capacity. TRC is the way to manufacture thin concrete parts with an extremely high load capacity. Even now, it is a very promising alternative for strengthening and repairing concrete structures, not least from a cost viewpoint. einforced concrete (RC) is the most successful building material of the past century, and most likely of the current century too. Combining steel bar reinforcement and concrete produces an almost ideal composite material. RC is extremely powerful, durable, and cost-effective. It fits nearly into every form, is extremely versatile and is therefore widely used as a construction material in buildings and bridges. There is just one problem: to achieve these features, RC structures need to have a minimum thickness in order to protect the metal reinforcement. A minimum concrete cover of 20–70 mm per layer is necessary to protect steel bar reinforcements from corrosion during a building's lifetime. However, bearing in mind that several layers are needed for most applications in major structures, this is no real limitation. But when such thick concrete sections are not required to resist loads, people usually start asking whether RC structures could be more lightweight, more elegant and more efficient. The answer is: Yes, they can – by using textile-reinforced concrete. R Fig. 1: Comparison of different reinforcing systems. New opportunities with textile-reinforced concrete (TRC) Textile reinforcement structures produced from carbon fibres represent an excellent alternative and complement existing reinforcement materials made from steel. Textile-reinforced concrete (TRC) has the same advantages as traditional RC, but also offers some new opportunities. To produce textile reinforcements, continuous yarns or rovings are processed in a planar structure by a textile technique to produce an optimal alignment and arrangement of fibres in structural members (Figure 1). This in turn results in either a much higher load-bearing performance than fibre-reinforced concrete (FRC) with equivalent fibre content, or in a reduced Fig. 2: Hand lay-up process for laminating TRC. TRCs, as described in this article, are made from carbon fibre grid structures which are embedded in a fine-grained concrete matrix (Figure 2). The result is a composite material with remarkable properties and advantages in use: • No concrete cover is necessary to protect the reinforcement from corrosion since the reinforcing materials used do not corrode under normal environmental conditions. Considering that no concrete cover is needed, very thin strengthening layers JEC Composites Magazine / No44 October 2008

JEC COMPOSITES MAGAZINE - Issue #44 - October 2008 - Special Asia

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