Focus on lightweight textiles

Today, it is all about lightweight structures for building facades and shell structures. Industry has been using fibre reinforcement for quite some time especially in motor vehicle construction or in the sports sector. The added possibility of using carbon fibres in particular for the manufacture of extremely filigree concrete structures in the construction industry is relatively new and now a factor in inspiring both architects and manufacturers to new designs. For this reason SGL Carbon Group has organised an open innovation competition. It ran under the name of ‘carbocrete’ on the   ‘Innovationskraftwerk’ platform of the ‘Germany – Land of Ideas’ initiative in the spring of 2012 with the aim of searching for new application ideas and usage scenarios for carbon-fibre reinforced concrete. This composite material is about as new as it gets and offers some exciting benefits. It is as strong as steel reinforced concrete, yet up to 75% lighter and longer lasting. In contrast to components made from steel reinforced concrete, those made from carbocrete cannot rust, which makes them particularly suitable for contact with water. Over 300 ideas were submitted, demonstrating the use of the material in terms of outdoor spaces, weathering and lightweight design. First prize in the competition went to the team of designers from Leipzig, Stefan Paulisch, Uta Kleffling

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Source – SGL Carbon

and Pamela Voigt with their ‘carbocrete balconies’, plantable and sensually curved balconies to counteract the concrete desert character of our town centres. The competition also showed that the potential of this lightweight has only reached the start in terms of development.”

In current research projects at the RWTH Aachen University, the Technical University of Dresden or the Saxon Textile Research Institute (STFI) in Chemnitz work is being done to underpin the possibilities of organic design using 3D textile reinforcement with the necessary know-how and new material developments. So as part of a collaborative project with the Technical University of

Chemnitz, the FiberTech Group, Hentschke Bau GmbH in addition to Panadur GmbH and Metallbau Hausmann GmbH the STFI has developed a new hybrid material that has combines the advantages of textile reinforced concrete with those of glass fibre reinforced plastic in terms of strength, durability and design flexibility. 3D woven fabrics made from glass filament yarns in a mesh configuration are used for the reinforcement. To visualise the results a reference building was created that took the form of a pavilion made from pre-fabricated textile concrete components reinforced with glass

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Source – SGL Carbon

fibre. The textile reinforced concrete used a layer of biaxial warp knitted fabric as reinforcement made from alkali resistant glass fibres (2400 tex). It was constructed from four layers of glass fabric to create building components with a thickness of 10 mm and a tensile strength of up to 165 MPa. To prevent the two materials tearing or decoupling in terms of their mechanical, chemical and thermal properties an intermediate layer was used consisting of epoxy resin and polyester honeycomb unwoven.

HERING, manufacturer of building materials has implemented a similar development in cooperation with the RWTH Aachen University, creating a betoShell fascia system from fascia panels that are only 30 mm thick and equipped with a 3D textile reinforcement that is able to withstand wind

pressures of up to 1.80 kN/m². The SITgrid spacer textile from V. Fraas Solutions was used for its extremely high load bearing capacity and particularly low intrinsic weight. This was tailored especially to the requirements of fascia elements and consists of two glass fibre layers 10 mm apart which are joined together through rigid compression by pile threads. A production line allows the concrete fascia panels to be manufactured in large dimensions up to 6,000 x 3,000 mm. Its low weight has advantages for transport and installation. In contrast to comparable steel reinforced fascia components betoShell saves up to 80% in terms of the resources needed to manufacture the panels. Concrete fascias can be decorated with differently coloured aggregates in addition to being sandblasted, polished or acidified. Life Cycle Engineering Experts

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Source – Hering

(LCEE) Institute from Darmstadt was able to verify its superior life-cycle assessment compared to other fascia systems.

Lightweight structures using membrane textiles have their advantages especially for the construction of large shell structures for football stadia or airports. Over the last few years Verseidag Indutex GmbH from Krefeld has become one of the market leaders in this area with the erection of a number of spectacular buildings. The company manufactures high quality fabrics made from glass or polyester fibres and coats these with PTFE and / or PVC for protection against the effects of weathering. In addition the fabrics are equipped with a low E coating that prevents the heat from permeating to the interior and reflects sunlight. This creates a pleasant interior climate whilst at the same time reducing energy costs for air-conditioning.

The construction of the Green Point football stadium in Capetown also utilised the optical possibilities of textile structures. The natural white glass fibre fabric was given a special coating, which during the day has the effect that sunlight is reflected from the textile skin, making it seem opaque, while at night the effect is reversed due to the fabrics permeability to light from the inside and the facade takes on a floating transparency. “In addition, while the fabric does indeed cut out rain and wind, it is at the same time permeable to air and prevents heat accumulating in the summer,” explains Dr. Peter Siemens, head of the development andinnovation department at Verseidag Indutex GmbH. Recently a digitally printable version has be made available and is suitable for shell structures in roofs and facades.

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Source – Hering

So, carbon, glass and aramide fibres for reinforcement in combination with concrete offer the building industry ever greater possibilities to reduce the amount of material used. But what about lightweight construction in terms of automotives, air planes and wind turbines? Expect to read some interesting developments here in the coming days and weeks.

Background picture: Verseidag

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