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<p>Concrete is a multifunctional construction material and currently the most employed one. Buildings built with reinforced concrete can provide excellent structures. However, current reinforced concrete constructions have a drawback – steel in concrete can corrode and can cause significant damage. To prevent this, concrete, dependent on its ambient surrounding, has to be protected by a thick concrete cover. This leads to a high material, resource and energy consumption and notable carbon dioxide emissions. Furthermore, the service life of reinforced concrete is still limited to 40 to 80 years.</p><p>For decades, an alternative to steel reinforcement has been searched for. In Germany, the focus has been laid on non-metallic reinforcements such as glass and carbon. In the 1990s, basic research has begun in the field of textile reinforcement and shown very promising results. For 10 years now the material has been slowly transferred into practice.</p><p>For German companies and research institutions as well as the German government there is a future in carbon reinforced concrete – a further development of textile reinforced concrete (TRC). Carbon reinforced concrete shall be used for new constructions and for the strengthening of existing structures. Germany wants to build more sustainable and energy-efficient in the future and wants to reduce quickly the existing investment backlog. The market launch shallbe quick and extensive.</p><p>However, there are still numerous conditions that need to be established, e.g. thicker cross sections, suitable connection devices, economic production processes and appropriate guidelines. To set up these conditions, Germany is currently investing about 65 million euros(45 million euros public funds plus around20 million euros company funds) in the quick exploration of the material and anew construction design.More than 130 companies and research institutions from different industrial sectors participate in the currently largest research project C3 – Carbon Concrete Composite in the building industry. The aim is to establish all necessary conditions in order to widely apply the new construction design by 2020.</p><p>This paper provides an insight into the topic carbon reinforced concrete, the overall research project and all ongoing particular projects</p>

Against the background of global warming and the associated need to drastically reduce energy and resource consumption, action must also be taken in the building sector. Resource‐efficient construction methods must be used that nevertheless allow the increasing construction tasks in areas such as infrastructure and housing to continue to be fulfilled. In order to successfully introduce a new construction method to the market, the aspects of recyclability and economic efficiency are essential, in addition to important government requirements for climate neutrality and technical performance. Above all, the economic viability, that is, the economic advantageousness, as well as its simple applicability compared to competing systems, decides on the success and widespread use of a new technology. Carbon reinforced concrete, with its outstanding technical properties and simultaneous material efficiency, is an important building block toward climate neutrality in the construction industry. It is a promising technology that still has to prove its economic advantages and robust applicability under market conditions. In addition to the infrastructure sector, there is great potential in the area of housing creation, which needs to be tapped for carbon reinforced concrete. For this challenge, it is necessary to design a competitive value chain that allows the realization of marketable products in mass production on existing plant technology. The article gives a short overview of the economic and ecological status quo in the field of prefabricated construction with carbon concrete, using the example of the C3‐result building CUBE. In particular, the CUBE‐BOX, which is made of prefabricated and semi‐prefabricated parts, is examined in more detail and the carbon reinforced concrete components used are compared with classic reinforced concrete constructions in terms of sustainability. In this context, the conceivable global climate protection contribution of the carbon reinforced concrete construction method is forecast based on potential market segments.

The building sector accounts for approx. 40% of total energy consumption and approx. 36% of all greenhouse gas emissions in Europe. As the EU climate targets for 2030 call for a reduction of greenhouse gas emissions by more than half compared to the emissions of 1990 and also aim for climate neutrality by 2050, there is an urgent need to achieve a significant decrease in the energy use in buildings towards Nearly Zero-Energy Buildings (nZEBs). As the energy footprint of buildings includes the energy and greenhouse gas consumption both in the construction phase and during service life, nZEB solutions have to provide energy-efficient and less carbon-intensive building materials, specific thermal insulation solutions, and a corresponding design of the nZEB. Carbon reinforced concrete (CRC) materials have proven to be excellent candidate materials for concrete-based nZEBs since they are characterized by a significantly lower CO2 consumption during component production and much a longer lifecycle. The corresponding CRC technology has been successively implemented in the last two decades and first pure CRC-based buildings are currently being built. This article presents a novel material system that combines CRC technology and suitable multifunctional insulation materials as a sandwich system in order to meet future nZEB requirements. Because of its importance for the life cycle stage of production, cost-efficient carbon fibers (CF) from renewable resources like lignin are used as reinforcing material, and reinforcement systems based on such CF are developed. Cutting edge approaches to produce ultra-thin lightweight CF reinforced concrete panels are discussed with regard to their nZEB relevance. For the life cycle stage of the utilization phase, the thermal insulation properties of core materials are optimized. In this context, novel sandwich composites with thin CRC layers and a cellular lightweight concrete core are proposed as a promising solution for façade elements as the sandwich core can additionally be combined with an aerogel-based insulation. The concepts to realize such sandwich façade elements will be described here along with a fully automated manufacturing process to produce such structures. The findings of this study provide clear evidence on the promising capabilities of the CRC technology for nZEBs on the one hand and on the necessity for further research on optimizing the energy footprint of CRC-based structural elements on the other hand.