No abstract

Today's challenges comprise climate change, urbanization, and demographic change. The building industry is of major technical and economic importance for these subjects. Due to the versatility, structural concrete is the major applied material in building industry. The associated cement production contributes significantly to the CO2 emissions. Hence, new technologies and planning methods as well as production and recycling techniques have to be developed to account for a fast changing world and to reduce the carbon footprint. High‐performance materials, such as textile reinforced concrete, in combination with new construction methods and conceptual designs, can reduce the material usage significantly. In this paper, new construction methods as well as conceptual designs are proposed, which result in economic structural members.

Bond behaviour of pre-tensioned CFRP tendons in UHPFRC The combination of pre-tensioned CFRP (Carbon Fiber Reinforced Plastics) tendons in UHPFRC (Ultra High Performance Fiber Reinforced Concrete) makes filigree and durable constructions with long spans possible, especially with the application of folded and curved shells. Due to a high corrosion resistance of pre-tensioned CFRP tendons, the concrete cover is governed by the bond behaviour to reach a crack-free transmission zone. In this paper the results of an experimental study on the bond behaviour of pre-tensioned CFRP tendons are presented and an outlook for planned investigations on UHPFRC shells is given.

No abstract

Sandwich‐structured composites represent an efficient method to establish building envelopes which concurrently satisfy several demands. Besides low self‐weight with high load‐bearing capacity, sandwich panels provide sufficient physical properties, such as heat and sound insulation. In general, sandwich panels for applications in building industry are made of flat or thin profiled metal sheets or thick concrete facings. However, standard elements are limited to short spans. In contrast, spatially shaped concrete structures with folded plate or curved geometry provide high stiffness and load‐carrying capacity even for thin elements. The application of folded plate and curved concrete structures to sandwich panels combines the advantages of both construction methods. To realize thin facings in various shapes, high performance cementitious composites are advantageous. Ultra‐high performance fiber reinforced concrete (UHPFRC) provides high compressive and tensile strengths with ductile material behavior. The application of non‐corrosive reinforcement, for example, carbon fiber reinforced polymer (CFRP), allows for filigree concrete elements with a thin concrete cover to only fulfill bond requirements. For sandwich panels with folded plate or curved facings, new production methods are necessary to account for cross‐sections in various shapes. This paper introduces the basic ideas of non‐planar concrete sandwich elements for long‐span roof structures and the developed production methods.