Auf dem Weg zu mehr Ressourceneffizienz im Bausektor

Kick-off event of the BMBF funding measure ReMin

It has become particularly clear in recent months that the availability of raw materials is generally of essential importance and an indispensable prerequisite for achieving climate targets. It is not only the raw materials for key technologies such as economically strategic metals that are important, but also those needed for the construction of roads, buildings and other structures. In order to secure these mineral raw materials in the long term, in particular through circular economy approaches, a total of 17 interdisciplinary consortia have been working on this topic in a variety of ways for around a year as part of the BMBF's "Resource-efficient circular economy - construction and mineral material cycles" (ReMin) funding measure. From July 6 to 7, the consortia presented themselves and their current research and development results at the kick-off event in Clausthal-Zellerfeld.

The BMBF framework program "Research for Sustainable Development" (FONA) has already shown in previous funding measures, such as r4, that resource-efficient raw material strategies play an important role for Germany and the EU in the context of the European Green Deal. In his welcoming speech in the Aula Academica of Clausthal University of Technology, Thomas Bartelt (BMBF) emphasized the importance of applied research in ReMin for the German Raw Material Efficiency Programme. He also presented other current and future planned measures, such as the "Circular Economy Initiative Deutschland" and the European research funding network ERA-MIN 3, and wished the consortia every success in implementing the project content.

As keynote speaker, Dr. Alexander Röder, Managing Director of Institut Bauen und Umwelt e.V. (IBU), impressively conveyed the importance and complexity of a solid data basis for the life cycle assessment of buildings and building components. As part of the development towards a more climate and environmentally friendly construction industry, reliable data, for example from the EPDs (Environmental Product Declaration) of individual construction products, is of great importance. In particular, it should be emphasized that around 50 percent of the energy used in modern buildings is accounted for by the raw materials. Efficient building raw material strategies are therefore essential for the life cycle assessment of buildings. Gaps still need to be closed, particularly in the areas of deconstruction and recycling. The transfer and networking with the ReMin funding measure could provide good impetus here.

The RekoTi, Precast 2.0 and MIN-LOOP projects presented their research in the first thematic block "Construction in the circular economy". The approaches showed how municipal civil engineering can be made more resource-efficient through intelligent observation, analysis, calculations and digital tools. Moving images impressively demonstrated how buildings scheduled for demolition can be digitized and how new, reusable components can be produced from construction elements during demolition using saws. Initial investigations into the specific use of recycled sand from construction waste for innovative hybrid ceiling elements delivered promising results.

The second thematic block covered "construction waste". A total of seven project networks are dedicated to this area, including the R-ZiEMENT, FaBeR, LIBS-ConSort and ReCyCONtrol projects. Right at the beginning, Dr. Christoph Müller, VdZ Technology gGmbH, pointed out the challenges facing the cement industry in Germany with regard to achieving the climate targets. The use of brick and masonry rubble as a component of R-cements is one approach to conserving resources.

The recycling of carbon and glass fiber concretes as well as the removal of impurities by means of sensor-based sorting can also be effective. Initial results from the selective crushing of carbon concrete and the use of crushed concrete as aggregate are promising. In the future, concrete could also be produced using self-learning systems. "There must be many ways that together lead tolower-CO2 concretes," said Prof. Dr. Michael Haist from the University of Hanover. A statement that underlines the various ReMin approaches.

On the second day of the event, RECBest, GipsREC 2.0 and REALight presented further alliances in the "Construction waste" thematic block. Highly topical issues such as efficient hedging strategies with regard to the contaminant asbestos or the recycling of gypsum fiberboard and the investigation of other sources of secondary gypsum were presented here. Asbestos can be reliably detected in existing buildings thanks to sampling plans that have been co-developed. However, asbestos investigation in the building is essential for effective selective demolition. Furthermore, initial tests on gypsum fiberboard recycling showed promising results. In the REALight network, which is investigating the production of lightweight granulates from brick-containing masonry rubble and other industrial by-products, the production of lightweight granulates, which has already been tested on a laboratory scale, is currently being transferred to a larger scale. The process also uses flue gas desulphurization to produce FGD gypsum.

The remaining six consortia presented their work in the last thematic block "Waste incineration ash, slag and mining residues": ASHCON and EMSARZEM are working on innovative processing technologies for waste incineration ashes (WIP), such as electrodynamic fragmentation and selective grinding processes. Initial results from the EMSARZEM network show how the material flows of ferrous and non-ferrous metals and minerals behave during processing. This is an important finding in order to understand how valuable metals can be better removed from the ashes and how the mineral fraction can be kept free of pollutants. The BAUSEP network is also looking at waste incineration plants as well as slag from the steel industry. The SABINE and SlagCEM consortia are also researching the latter. They are investigating whether the materials are suitable as concrete aggregates or as alternative, alkali-activated binding agents or for cement clinker production/iron recovery. Steel mill slags are generally suitable for the uses investigated. SlagCEM presented the results of initial melting tests, which focused on process optimization. Further systematic melting tests are to pave the way for industrial implementation.

The REMINTA project used the example of the tailings ponds of the former Rammelsberg ore mine in Goslar to demonstrate that mining residues can also make a significant contribution to the supply of raw materials. In addition to economically strategic metals, the muddy remains of the ore processing at Bollrich also contain the secondary rock Wissenbach slate, which has come into focus as a mineral raw material for the cement industry. In addition to technical implementation, acceptance research is a central aspect of the project. The dialog revealed a generally positive attitude among local residents. The concrete planning of the long-term project can move forward, explained Prof. Daniel Goldmann from IFAD at Clausthal University of Technology and also Vice President for Research, Transfer and Transformation at the university.

The kick-off event organized by the CUTEC Clausthal Environmental Technology Research Center showed that the topics dealt with in the ReMin funding measure are highly diverse and yet closely linked in many places. In the future, this interdisciplinary network funded by the TReMin accompanying research project must be used to significantly advance the circular economy and resource efficiency in the construction sector. The ReMin status conference will take place again next year in Clausthal-Zellerfeld, where the latest findings from the networks will be presented and discussed.

Authors: Marie Gentzmann, Federal Institute for Geosciences and Natural Resources, BGR, and Andre Bertram, CUTEC


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Picture gallery of the event