Circular economy - Recreate

April 22, 2025
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*German version of the interview is below*

In this interview, we speak with Prof. Angelika Mettke from BTU Cottbus–Senftenberg, one of the pioneering researchers in structural reuse in Europe. Drawing on decades of hands-on experience, Prof. Mettke reflects on the evolution of concrete element reuse in Germany, the long road from pilot projects to building codes, and why now might finally be the right time for circularity in construction to scale.

Hello, Prof. Mettke. Thank you for finding time for this interview. For starters, can you introduce yourself a bit and tell us about your background, your role, and your organization’s role in the project? How did it all start?

I have been working at BTU since 1975. Initially, I qualified with a degree in engineering, and the next step was obtaining my diploma as an engineer. In 1995, I earned my PhD in engineering, focusing on the development of decision-support tools for the preparation of renovation measures in industry for the reuse of building elements and components. In 2009, I obtained my habilitation, focusing specifically on the reuse of concrete elements, particularly those from prefabricated construction, and the recycling of mineral construction debris, or rather, the high-quality recovery of construction waste. Originally, the area was called “Construction Recycling,”, but now it’s referred to as my “research area,” which I developed independently. I had no public financial resources for personnel. However, I had the opportunity to raise funds through research projects, allowing me to employ scientific staff.

Satu Huuhka visited here in Cottbus at BTU and had the opportunity to speak with me. She found my work interesting and organized another visit with a delegation, which included a German-speaking colleague. During this visit, I gave a lecture on the topic of “Reuse of Concrete Elements.” Afterwards, she asked me what I thought about collaborating on a research project. So, between Finland and Cottbus. I was thrilled about this request. Of course, I welcomed such an international collaboration, which had not existed before. First, we needed to investigate where there were gaps in expertise and determine how we could work together. Then, Satu searched for funding opportunities at the European level, and we did the same for Germany. Then Satu said, “You have a lot of knowledge; you should take the lead. You have expertise, experience, and extensive research on this topic.” For Germany, I took on the leadership role, but the overall leadership should be with Finland—after all, the idea to initiate a European project came from Satu. That’s how it developed. When we formulated the application, I had only one research assistant: Viktoria Arnold, a graduate of the Siberian University of Krasnoyarsk, and both of us worked on the research proposal. This is how our ReCreate project came about. You asked me why I participated so eagerly in this project. Well, of course, I wanted to. Buildings constructed with prefabricated elements in modular construction can also be found in Europe and are not a national peculiarity. Satu was active and involved further project partners, such as the Netherlands, Sweden, and Croatia. This consortium was formed, and my particular interest was in situating this topic in a European context. In this constellation, we have other strengths that help accelerate the necessary transformation process in the construction sector, compared to just Mettke at BTU in Cottbus alone. In a cluster, we can achieve more, both in construction and environmental policy, and that is important. Especially now, through the climate discussion, the topic is gaining significance because the reuse of concrete components retains the embodied energy.

What motivated you to join the project?

As already mentioned, I started dealing with the topic of reuse more than 30 years ago. This was not primarily for climate protection reasons, but due to the resource scarcity in construction in East Germany, which presented me with great challenges. The necessity of addressing this issue arose from the fact that buildings in industrial and commercial construction were being demolished shortly after their useful life, after 10, 12, or 15 years. I made every effort to save the concrete elements used. Initially, quality testing of the concrete elements was the focus. In this, usability, constructional, and building-physical parameters played a role. After gaining access to buildings scheduled for demolition, I contacted several companies with my request to attempt to dismantle construction elements from the structural system. The most powerful construction company at the time, the Construction and Assembly Combine Coal and Energy, eventually agreed to try dismantling some elements of a single-story hall. I found that these buildings, constructed in modular construction, were dismantlable, even though they were not originally designed for deconstruction. This experience made it clear how important it is to assess unused buildings and, if conservation measures are excluded, to consider secondary reuse options for concrete elements already used. Furthermore, deconstruction considerations must be integrated into the planning process.

There is a huge potential in existing reinforced concrete modular buildings, not only in Germany but also across Europe and worldwide. And if, with the ReCreate project, we can help manage our primary raw material resources efficiently, thereby reducing the ecological footprint and contributing to climate protection, this is a huge opportunity. Building on our own and new research findings, we can show the professional world beyond national borders that the reuse of concrete elements is feasible and of high relevance both from a social and economic perspective.

Tell me about the German donor building and the pilot that will be constructed. Can you tell me what is specific for the German cluster, the German donor building and the pilot?

Well, first of all, let me start with a preliminary note. I have been in contact with the company Ecosoil for many years now. Thanks to our collaborative work, the “selective demolition” business area has become established within the company. As is standard procedure, I contacted Ecosoil’s senior construction manager about current demolition projects. In Hohenmölsen, Saxony-Anhalt, Ecosoil Ost GmbH had been commissioned to demolish a five-story prefabricated building by two floors. I also asked if they notified the relevant parties in advance. Through Ecosoil, I got in touch with the property owner, the housing association in Hohenmölsen. At the time, I wasn’t familiar with Hohenmölsen, which is located in the federal state of Saxony-Anhalt. I introduced myself over the phone and scheduled an on-site meeting, and that’s how things started moving forward in the first place. After a rough assessment that almost 500 concrete elements would need to be dismantled, I proposed the idea of constructing a pilot within the scope of the ReCreate project. Although I had ideas, I couldn’t make the final decision; it had to be approved by the city. It was important to me to determine whether there was a need for the construction of a public building. This led to an initial meeting with Mr. Luckanus, the managing director of the housing association, and Mr. Haugk, the mayor of Hohenmölsen. During this meeting, I presented our previous projects and initiatives. We had already implemented measures such as constructing new buildings using recycled concrete elements. I learned that the “old” spaces for youth centres would no longer be available in the foreseeable future. Based on a conceptual design with a selected range of P2 building-type elements for a youth centre, which I had created for another city, I was able to gain the mayor’s interest. I asked them if they could envision something similar within our project.

The mayor expressed the need for a community centre (clubhouse) and informed me about the old clubhouse, which was scheduled for demolition, and the plans to accommodate different users in the new facility. He explained in detail why certain features were necessary. However, he mentioned that the original concept I had presented, based on the P2 type, had a gross floor area that was too large (400 m²). I assured him that adjusting the concept would not be an issue. Following this, I asked him about the specific spaces they required. Based on several rounds of consultations with the representatives of the city of Hohenmölsen regarding usage and space requirements, and with us, my research assistant, architect Christoph Henschel, developed the concept for the youth centre. The youth centre, with its diverse uses (including multi-purpose and hobby rooms, offices, kitchen, etc.), has a gross floor area of ​​approximately 835 m² spread over two floors. We developed a total of six design variants for this building because the spaces had to be adapted to the changing needs of future users, including various clubs.

So, was the decision on which design to choose influenced by the organizations that will eventually be in the building?

Yes, as just mentioned, that was the case. For the most recently agreed-upon concept for the youth center, we developed an exposé that will serve as the basis for the tender. With the help of students, we also built a model to improve visualization. In addition to integrating 160 dismantled, used concrete elements, steel beams and timber stud walls are to be used. This is due to the geometric dimensions of the rooms. The city of Hohenmölsen, as the public client, has been promised financial support for this sustainable construction project. The completion of the youth centre is expected in 2026.

Should difficulties arise and the construction project in Hohenmölsen be called into question, I was able to initiate a second pilot project near Cottbus as a backup option.

I would also like to point out one aspect: initially, there were difficulties in providing a storage area for the dismantled concrete elements in Hohenmölsen. The need to temporarily store the dismantled elements arises from the time difference between the moment the concrete elements are dismantled and their reassembly date. In the end, the city designated a temporary storage area close to the construction site.

So, the city doesn’t want to invest in spaces for the disposal of the elements because they still need to assess the project’s value. Does this create a problem when you initially want to start something?

I must state that there is currently no functioning “handling” system for large-format concrete elements. It must be assumed that temporary storage for used concrete elements will be necessary. The establishment of decentralized building component exchanges combined with web-based platforms could provide a solution to ensure optimal marketing for used concrete elements. I could imagine that stationary construction material recycling plant operators could temporarily store the used concrete elements. If they are not in demand, there would still be the option of material recycling or shredding into recycled material. This is an idea, but whether it can be implemented is still to be evaluated.

What does collaboration look like within your country’s cluster? Is there strong collaboration? Do you maintain good communication with project partners in the German cluster?

I can look back on an excellent collaboration with the industry partners involved in the ReCreate project. This cooperation is based on a long-standing, reliable, and constructive relationship with the engineering firm Jähne and the deconstruction company Ecosoil Ost GmbH. It is important that we support each other, communicate openly, and exchange ideas. We meet regularly, but there are also many operational matters that need to be coordinated, which we usually clarify over the phone or in personal discussions. In short, the collaboration with the construction industry partners is outstanding.

The “new” project partners include the city of Hohenmölsen and the company Lohmann & Robinski – web solutions. The latter has extensive experience with digital work methods, helping us digitize work results within the German national project. Additionally, having the city of Hohenmölsen as a local partner is crucial, as they are familiar with the regional conditions and authorities. All the necessary requirements for such a construction project fall under the city’s jurisdiction through the building authority. At the same time, we aim to ensure that construction of the youth center can hopefully begin there next year.

We also plan to organize an international ReCreate project partners meeting, similar to those held in Eindhoven, Helsingborg, and Tampere, to assess the condition of the used concrete elements and observe the reassembly process. Significant support is expected from our local partner. In my experience, having a local partner is highly beneficial, as they have a strong interest in this sustainable initiative and are motivated to drive it forward.

Do you have some kind of internal motivation for the project? Do you have any personal stakes or intrinsic motivation that drives you?

Yes, of course! The reuse of building components is my life’s work! I have dedicated myself to this topic. Viktoria was there: In 2016, I received the German Environmental Award for this commitment—one of the most prestigious awards in Europe. Together with a company, we received this prize for the efficient use of resources.

My passion lies in reusing valuable materials because I was raised that way in my family home. My parents—my father, a self-employed metalworker—built many objects from reused materials, whether lamps, scooters, tricycles, wheelbarrows, or even a tractor. He used materials he found at the landfill.

This mindset shaped me from an early age. So yes, there is passion involved—both emotionally and professionally.

In your opinion, what are some of the major challenges that the project is facing? We’ve already identified certain aspects, but could you elaborate on them?

Yes, the biggest challenge for the project is the various international aspects that need to be considered. The necessary exchange between project partners must be maintained. In Germany, this is somewhat easier due to the already existing network, but new partners are always being added. The professional exchange takes place through regular coordination between my colleagues and me, but it is still somewhat time-consuming. The network we have built in our German cluster makes collaboration easier now. However, with new partners, a certain level of trust must first be established. The administrative tasks that always arise in EU projects take up a significant portion of the time.

That being said, what about the project in general? In your opinion, what do you believe are the major challenges that everyone has to face at the European level?

You know, generally speaking, I would wish that through this European consortium, the idea of reusability is established worldwide. With these clusters, we can widely spread the results, not just in Europe. There will be a film about the pilot project to show that it is being implemented exemplarily in Finland, the Netherlands, Sweden, and Germany – so it works everywhere. That’s the challenge: to show that existing resources, i.e., used concrete elements, are fully reusable in a secondary way. Building with existing structures has top priority. There is no alternative to the limited available mineral raw materials. We must demonstrate this worldwide, because many countries aspire to the European standard of living. Construction is happening worldwide. If we can show that we can also build with existing structures, in a sustainable way, and also architecturally interesting, then this meets our research goal. For example, the pilot project in Finland will look different from the one here in Germany. So, we will be able to present a variety of solutions. The construction connections and the structural development of the range of elements differ. We can learn from Finland or the Netherlands – from their building systems and joining techniques, and vice versa. This networking is, in my opinion, very valuable.

What kind of impact would you like for the project to have someday? Do you believe that after the project is completed, it will be easier to update the standard at the European level?

On the German side, I currently have the development of a German standard on the agenda, but this process takes time. It typically spans several years, as a standard must be thoroughly reviewed and objections from experts considered before its publication. At present, a used building component is considered an unregulated construction product under both EU and German law.

We will not be able to solve all the problems in the ReCreate project. The tasks are very complex and extensive. New questions will also arise from our research. What is important to me is that rules and standards are developed to facilitate the entire process. This is a big challenge. For example, we would like to develop a standard solution for warranty and liability issues related to the use of used concrete elements – in collaboration with legal expertise. A guideline needs to be created that outlines which actor is responsible for which performance, and what steps need to be carried out to effectively plan and implement reuse.

The EU Construction Products Regulation governs market access and the use of construction products. The 16 state building codes in Germany define the general requirements for buildings, which are further specified by the Technical Building Regulations.

In my opinion, a harmonized specification according to EU regulations would help to draw more attention to the reuse of used concrete elements. So far, there is no harmonized assessment or standard for this.

So, maybe it’s still too early, considering there’s a lot of research yet to be conducted on this topic. However, that’s the task of the ReCreate project: to establish the necessary research and then present it to policymakers so they can incorporate it into policies, regulations, and standards. Do you agree?

Yes, I agree. This is the next step. In the ReCreate project, we are laying the essential foundations – supported by scientifically based methods. The solutions developed will, I hope, be incorporated into an EU standard.

We always like to conclude interviews with the question: Who is Angelika Mettke, and what does she enjoy doing when she’s not working on the ReCreate Project or at her university? What are her favorite activities in her spare time?

I enjoy spending time with my grandchildren, being outdoors, and in my garden. I have a house and a weekend property. There’s always something to do there, and I enjoy it. It’s a nice balance, a contrast to office work and mental work. I can get some exercise in the fresh air, play outside with my grandchildren, and at the same time, observe animals and enjoy the birdsong. Yesterday, for example, I saw a hedgehog in our garden. The older I get, the more I appreciate the wonder of nature. That’s why it’s important to me that nature and our habitat, our landscape, are preserved and disturbed as little as possible. This aligns with my actual responsibilities and my job: conserving resources and interfering with nature with little to no impact. I plant flowers, shrubs, and trees. I know that I’ve contributed something in my small area of ​​activity; to doing something socially meaningful. I enjoy spending my holidays on the Baltic Sea in Warnemünde and Kühlungsborn, as well as in various places on the islands of Usedom and Rügen. The atmosphere is unique. But I am also aware that every country has beautiful places.

 

German version:

 

Hallo Frau Prof. Mettke. Vielen Dank, dass Sie Zeit für dieses Interview gefunden haben. Können Sie sich zunächst einmal kurz vorstellen, uns etwas über Ihren Hintergrund, Ihre Rolle und die Rolle Ihrer Organisation in diesem Projekt erzählen? Wie hat das alles angefangen?

Ich bin seit 1975 bei der BTU tätig. Zunächst qualifizierte ich mich mit dem Abschluss als Ingenieur, der nächste Schritt war die Erlangung des Diplom-Ingenieurs. Im Jahr 1995 promovierte ich im Fachbereich Ingenieurwesen zur Entwicklung von Entscheidungshilfen für die Vorbereitung von Sanierungsmaßnahmen in der Industrie zur Wiederverwendung von Bauelementen und Bauteilen. Im Jahr 2009 habilitierte ich mich, wobei ich mich speziell mit der Wiederverwendung von Betonelementen, insbesondere aus dem Fertigteilbau, und mit dem Recycling von mineralischem Bauschutt bzw. der hochwertigen Verwertung von Bauabfällen beschäftigte. Ursprünglich hieß der Bereich ” Bauliches Recycling”, aber jetzt wird er als mein “Forschungsbereich” bezeichnet, den ich eigenverantwortlich entwickelt habe. Ich hatte keine öffentlichen finanzielle Mittel für Personal. Aber hatte die Möglichkeit, über Forschungsprojekte finanzielle Mittel einwerben zu können und damit wissenschaftliche Mitarbeiter zu beschäftigen.

Satu Huuhka war zu Besuch hier in Cottbus an der BTU und hatte die Gelegenheit, mit mir zu sprechen. Sie fand meine Arbeit interessant und organisierte einen weiteren Besuch mit einer Delegation, zu der auch ein deutschsprachiger Kollege gehörte. Bei diesem Besuch hielt ich einen Vortrag zum Thema „Wiederverwendung von Betonelementen“. Danach fragte sie mich, was ich von einer Zusammenarbeit bei einem Forschungsprojekt halte. Also, zwischen Finnland und Cottbus. Über diese Anfrage war ich hoch erfreut. Natürlich begrüßte ich eine solche, bis dato nicht vorhandene internationale Zusammenarbeit. Zunächst müssen wir untersuchen, wo es Lücken im Fachwissen gibt, und feststellen, wie wir zusammenarbeiten können. Dann hat Satu nach Finanzierungsmöglichkeiten auf europäischer Ebene gesucht, und wir haben das für Deutschland getan. Dann sagte Satu: “Ihr habt viel Wissen, ihr solltet die Gesamtleitung übernehmen. Sie verfügen über Fachwissen, Erfahrung und umfangreiche Forschungsarbeiten zu diesem Thema”. Für Deutschland übernehme ich die Leitung, aber die Gesamtleitung sollte Finnland übernehmen – schließlich stammt die Idee, ein europäisches Projekt zu initiieren von Satu. So hat sich das entwickelt. Als wir den Antrag formulierten, hatte ich nur eine wissenschaftliche Mitarbeiterin: Viktoria Arnold, Absolventin der Sibirischen Universität Krasnojarsk und wir beide haben mit am Forschungsantrag gearbeitet. So kam es also zu unserem ReCreate Projekt. Sie haben mich gefragt, warum ich so eifrig an diesem Projekt teilgenommen habe. Nun, natürlich wollte ich das. Gebäude, die mit vorgefertigten Elementen in Montagebauweise gebaut wurden, sind auch in Europa anzutreffen und keine nationale Besonderheit. Satu war aktiv und hat weitere Projektpartner einbezogen, wie die Niederlande, Schweden und Kroatien. Es entstand dieses Konsortium, und mein besonderes Interesse lag darin, dieses Thema im europäischen Kontext zu verorten. In dieser Konstellation haben wir andere Stärken, die dazu beitragen, den notwendigen Transformationsprozess im Bausektor zu beschleunigen, als nur Mettke an der BTU in Cottbus allein. In einem Cluster können wir mehr erreichen, auch bau- und umweltpolitisch, und das ist wichtig. Gerade jetzt, durch die Klimadiskussion, gewinnt das Thema an Bedeutung, weil durch die Wiederverwendung von Betonbauteilen die enthaltene graue Energie erhalten bleibt.

Was hat Sie dazu motiviert, an dem Projekt teilzunehmen?

Wie bereits erwähnt, habe ich vor mehr als 30 Jahren begonnen, mich mit dem Thema Wiederverwendung auseinanderzusetzen. Dies geschah nicht in erster Linie aus Klimaschutzgründen, sondern aufgrund der Ressourcenknappheit beim Bauen in Ostdeutschland, was mich vor große Herausforderungen stellte. Die Notwendigkeit sich dieser Thematik zu stellen, ergab sich daraus, dass Gebäude im Industrie- und Gewerbebau bereits kurz nach ihrer Nutzungsdauer, nach 10, 12, 15 Jahren, abgerissen wurden. Ich setzte alles daran, die verbauten Betonelemente zu retten. Zunächst standen Qualitätsuntersuchungen der verbauten Betonelemente im Vordergrund. Dabei spielten die Gebrauchstauglichkeit, bautechnische und bauphysikalische Parameter eine Rolle. Nachdem ich Zugang zu Bauten erhielt, die zum Abbruch anstanden, kontaktierte ich mehrere Unternehmen mit meinem Anliegen, versuchsweise Bauelemente aus dem Konstruktionsverbund zu demontieren. Der damalig leistungsstärkste Baubetrieb des Bau- und Montagekombinats Kohle und Energie erklärte sich schließlich bereit, einige Elemente der eingeschossigen Halle versuchsweise zu demontieren. Dabei stellte ich fest, dass diese in Montagebauweise errichteten Gebäude demontierbar sind, obwohl sie ursprünglich nicht für den Rückbau konzipiert wurden. Diese Erfahrung machte deutlich, wie wichtig es ist, nicht mehr genutzte Bauten auf den Prüfstand zu stellen und – sofern Erhaltungsmaßnahmen ausgeschlossen werden – sekundäre Nachnutzungsoptionen für schon einmal verbaute Betonelemente in Betracht zu ziehen. Darüber hinaus sind Rückbauüberlegungen bereits in den Planungsprozess zu integrieren.

Es ist ein großes Potenzial an existierenden Stahlbeton-Montagebauten nicht nur in Deutschland, sondern europa- und weltweit vorhanden. Und wenn wir mit dem Projekt „ReCreate“ dazu beitragen können, mit unseren primären Rohstoffressourcen effizient umzugehen und dadurch der ökologische Fußabdruck eingedämmt und außerdem ein Beitrag zum Klimaschutz geleistet werden kann, ist das eine riesige Chance, aufbauend auf unseren und neuen Forschungsergebnissen, über die nationalen Grenzen hinaus der Fachwelt zu zeigen, dass die Wiederverwendung von Betonelementen machbar  und volks- wie betriebswirtschaftlich  von hoher Relevanz ist.

Erzählen Sie mir von dem deutschen Spendergebäude und dem Pilotprojekt, das gebaut werden soll. Können Sie mir sagen, was das Besondere an dem deutschen Cluster, dem deutschen Spendergebäude und dem Pilotprojekt ist?

Nun, lassen Sie mich zunächst mit einer Vorbemerkung beginnen. Ich arbeite seit vielen Jahren mit der Firma Ecosoil Ost GmbH zusammen. Aufgrund unserer kooperativen Zusammenarbeit hat sich das Geschäftsfeld „selektiver Rückbau“ im Unternehmen etabliert.  In üblicher Verfahrensweise kontaktierte ich den Oberbauleiter der Firma Ecosoil zu aktuellen Rückbaumaßnahmen. In Hohenmölsen, Bundesland Sachsen-Anhalt, hatte die Ecosoil Ost GmbH den Auftrag erhalten, einen 5-geschossigen Plattenbau um 2 Geschosse zurückzubauen. Ich setzte mich mit dem Eigentümer des Hauses, der Wohnungsbaugesellschaft WOBAU in Hohenmölsen, in Verbindung. Ich stellte mich telefonisch vor und vereinbarte einen Vor-Ort-Termin; so kam die Zusammenarbeit überhaupt erst ins Rollen. Nach überschläglicher Feststellung, dass knapp 500 Betonelemente zu demontieren sind, regte ich an, ein Pilotprojekt zu errichten. Mir war es wichtig, zu erfahren, ob Bedarf an der Errichtung eines öffentlichen Gebäudes besteht. So kam es zu einem ersten gemeinsamen Treffen mit Herrn Luckanus, dem Geschäftsführer der Wohnungsbaugesellschaft, und dem Bürgermeister der Stadt Hohenmölsen Herrn Haugk. Bei diesem Termin habe ich unsere bisherigen Projekte und Initiativen zur Wiederverwendung vorgestellt. Ich habe in Erfahrung gebracht, dass in absehbarer Zeit die „alten“ Räumlichkeiten für Jugendtreffs nicht mehr zur Verfügung stehen werden. Auf der Grundlage eines konzeptionellen Entwurfs mit einem ausgewählten Elementesortiment vom Gebäudetyp P2 für ein Jugendzentrum, das ich für eine andere Stadt erstellt hatte, konnte ich das Interesse des Bürgermeisters gewinnen.

Der Bürgermeister äußerte nach mehreren Absprachen mit den örtlichen Akteuren den Bedarf an einem Jugendklub und informierte mich über das alte Klubhaus, das zum Abriss vorgesehen war. Er erläuterte ausführlich, warum bestimmte Merkmale notwendig waren. Er erwähnte jedoch, dass das ursprüngliche Konzept, das ich vorgelegt hatte, auf der Grundlage des P2-Typs eine zu große Bruttogeschossfläche aufweist (400m²). Ich versicherte ihm, dass eine Anpassung des Konzepts an das Elementesortiment aus dem P Halle Typ kein Problem darstellt. Auf Basis mehrere Abstimmungsrunden mit den Vertretern der Stadt Hohenmölsen zum Nutzungs-und Raumbedarf und uns, entwickelte mein wissenschaftlichen Mitarbeiter, Architekt Christoph Henschel das Konzept für das Jugendzentrum. Das Jugendzentrum mit den vielfältigen Nutzungen (darunter Mehrzweck- und Hobbyräume, Büros, Küche etc.) hat eine Bruttogeschossfläche von rund 835m² über zwei Geschosse. Für dieses Gebäude haben wir in Summe sechs Entwurfsvarianten konzipiert, weil die Räume an die wechselnden Anforderungen der künftigen Nutzer, darunter verschiedene Vereine, anzupassen waren.

Wurde die Entscheidung für ein bestimmtes Design von den Organisationen beeinflusst, die später in dem Gebäude untergebracht werden sollen?

Ja, wie gerade erwähnt, war das der Fall. Für die zuletzt einvernehmliche Konzeption für das Jugendzentrum wurde von uns ein Exposé entwickelt, das der Ausschreibung zugrunde gelegt wird. Mit Unterstützung von Studenten haben wir zudem zum besseren Vorstellungsvermögen ein Modell gebaut. Neben der Integration von 160 demontierten, gebrauchten Betonelementen sind Stahlträger und Holzständerwände zu verbauen. Dies ist auf die geometrischen Abmaße der Räume zurückzuführen. Die Stadt Hohenmölsen als öffentlicher Bauherr hat eine finanzielle Förderung für dieses nachhaltige Bauvorhaben in Aussicht gestellt bekommen. Mit der Errichtung des Jugendzentrums wird in 2026 gerechnet.

Sollte es zu Schwierigkeiten kommen und das Bauvorhaben in Hohenmölsen in Frage gestellt werden, konnte ich ein zweites Pilotprojekt in der Nähe von Cottbus als Backup-Option initiieren.

Ich möchte noch auf einen Aspekt hinweisen: in Hohenmölsen gab es anfangs Schwierigkeiten, eine Fläche zur Zwischenlagerung für die demontierten Betonelemente bereit zu stellen. Die Notwendigkeit, die demontierten Elemente zwischenzulagern ergibt sich aus der zeitlichen Differenz zwischen dem Zeitpunkt des Anfalls der demontierten Betonelemente und deren Remontage-Termin. Schlussendlich hat die Stadt eine Zwischenlagerfläche in unmittelbarer Nähe des Baustandortes ausgewiesen.

Die Stadt wollte also nicht in die Zwischenlagerung der Elemente investieren, weil sie noch keine Mittel für das Projekt hat. Ist das ein Problem, wenn etwas aus gebrauchten Elementen gebaut werden soll?

Ich muss konstatieren, dass es derzeit noch kein funktionierendes „Handling“ für großformatige Betonelemente gibt. Es muss davon ausgegangen werden, dass eine Zwischenlagerung für gebrauchte Betonelemente erforderlich ist. Die Einrichtung von dezentralen Bauelemente-Börsen in Kombination mit web-basierten Plattformen könnten Abhilfe schaffen, um eine optimale Vermarktung für gebrauchte Betonelemente sicherzustellen. Ich könnte mir vorstellen, dass stationäre Baustoff-Recycling-Anlagenbetreiber die gebrauchten Betonelemente zwischenlagern. Werden diese nicht nachgefragt, bestünde immer noch die Möglichkeit der stofflichen Aufbereitung bzw. Schredderung zu Recyclingmaterial. Das ist eine Idee, aber inwieweit sie sich umsetzen lässt, ist noch zu prüfen.

Wie sieht die Zusammenarbeit innerhalb des Clusters in Ihrem Land aus? Gibt es eine starke Zusammenarbeit? Pflegen Sie eine gute Kommunikation mit den Projektpartnern im deutschen Cluster?

Ich kann auf eine hervorragende Zusammenarbeit mit den im Projekt „ReCreate“ involvierten Industriepartnern zurückblicken. Die Zusammenarbeit fußt auf einen seit Jahren zuverlässigen und konstruktiven Kontakt mit dem Ingenieurbüro Jähne und dem Rückbauunternehmen Ecosoil Ost GmbH. Es ist wichtig, dass wir uns gegenseitig unterstützen, offen miteinander umgehen können und Ideen austauschen können. Wir treffen uns regelmäßig, aber zudem sind oftmals operativ  Sachverhalte abzustimmen, die wir meistens am Telefon oder in persönlichen Gesprächen klären. Also, die Zusammenarbeit mit den Partnern der Bauwirtschaft ist hervorragend. Zu den „neuen“ Projekt-Partnern gehören die Stadt Hohenmölsen und die Firma Lohmann und Robinski – web solutions. Letztere haben umfangreiche Erfahrungen mit digitalen Arbeitsmethoden, um uns bei der Digitalisierung von Arbeitsergebnissen im deutschen Landesprojekt insgesamt zu unterstützen. Wichtig ist außerdem, dass wir mit der Stadt Hohenmölsen einen Partner vor Ort haben, der die regionalen Gegebenheiten und die Behörden kennt. Alle Voraussetzungen für ein solches Bauprojekt liegen zum einen in der Zuständigkeit der Stadt durch das Bauamt, zum anderen wollen wir dafür sorgen, dass im nächsten Jahr dort hoffentlich mit dem Bau dieses Jugendclubs begonnen wird. Wir wollen auch ein Clustertreffen organisieren, ähnlich wie wir es in Eindhoven, Helsingborg und Tampere hatten, um sehen können, in welchem Bauzustand sich die gebrauchten Betonelemente befinden und wie die Remontage erfolgt.

Von dem Partner vor Ort wird also eine erhebliche Unterstützung erwartet. Meiner Erfahrung nach funktioniert ein Partner vor Ort besser, weil er ein starkes Interesse an dieser nachhaltigen Initiative hat und sie vorantreiben will.

Haben Sie eine Art innere Motivation für das Projekt? Haben Sie einen persönlichen Einsatz oder eine intrinsische Motivation, die Sie antreibt?

Ja, natürlich! Die Wiederverwendung von Bauteilen ist mein Lebenswerk! Ich habe mich diesem Thema verschrieben. Viktoria war dabei: Ich habe 2016 den Deutschen Umweltpreis für dieses Engagement erhalten, eine der renommiertesten Auszeichnungen in Europa. Zusammen mit einem Unternehmen haben wir einen Preis für den effizienten Einsatz von Ressourcen erhalten. Meine Leidenschaft liegt in der Wiederverwendung von Werten, weil ich in meinem Elternhaus so erzogen wurde. Meine Eltern – mein Vater als selbständiger Handwerker im Metallbau hat viele Gegenstände aus gebrauchten Materialien gebaut, sei es Lampen, Motorroller, Dreiräder oder Schubkarren oder sogar ein Traktor. Er hat Materialien verwendet, die er auf der Mülldeponie gefunden hatte.

Dieses Verhalten hat mich sozusagen von Kindesbeinen an geprägt. Ja, es ist also auch Leidenschaft im Spiel, sowohl emotional als auch beruflich.

Was sind Ihrer Meinung nach die größten Herausforderungen, denen sich das Projekt stellen muss? Wir haben bereits einige Aspekte genannt, aber könnten Sie diese näher erläutern?

Ja, die größte Herausforderung für das Projekt sind die verschiedenen internationalen Aspekte, die zu berücksichtigen sind. Der notwendige Austausch unter den Projektpartnern muss gepflegt werden. In Deutschland ist dies aufgrund des bereits bestehenden Netzwerks etwas einfacher, aber es kommen auch immer neue Partner hinzu. Der fachliche Austausch erfolgt durch regelmäßige Abstimmungen zwischen meinen Kollegen und mir, ist aber noch etwas zeitaufwändiger. Das Netzwerk, das wir in unserem deutschen Cluster aufgebaut haben, macht die Zusammenarbeit jetzt einfacher. Allerdings muss man bei neuen Partnern erst einmal ein gewisses Vertrauen aufbauen. Die administrativen Aufgaben, die bei EU-Projekten immer anfallen, nehmen einen erheblichen Teil der Zeit in Anspruch.

Wie sieht es nun mit dem Projekt im Allgemeinen aus? Was sind Ihrer Meinung nach die größten Herausforderungen, denen sich alle auf europäischer Ebene stellen müssen?

Wissen Sie, generell würde ich mir wünschen, dass durch dieses europäische Konsortium die Idee der Wiederverwendbarkeit weltweit etabliert wird. Mit diesen Clustern können wir die Ergebnisse weit verbreiten, nicht nur in Europa. Es wird ein Film über das Pilotprojekt geben, um zu zeigen, dass es in Finnland, den Niederlanden, Schweden und Deutschland exemplarisch umgesetzt wird – es funktioniert also überall. Das ist die Herausforderung: zu zeigen, dass wir vorhandene Ressourcen, also gebrauchte Betonelemente in Gänze sekundär nachnutzbar sind. Bauen mit dem Bestand hat oberste Priorität. Zu den begrenzt verfügbaren mineralischen Rohstoffen gibt es keine andere Alternative. Das müssen wir weltweit demonstrieren, denn viele Länder streben nach dem europäischen Lebensstandard. Es wird weltweit gebaut. Wenn wir zeigen können, dass wir auch mit vorhandenen Strukturen bauen können, auf nachhaltige Weise, auch architektonisch interessant, dann entspricht dies unserem Forschungsziel. Beispielsweise wird das Pilotprojekt in Finnland anders aussehen als das hier in Deutschland.  Also werden wir eine Vielzahl von Lösungen vorstellen können. Die Konstruktionsverbindungen und die konstruktive Durchbildung des Elementesortiments sind unterschiedlich. Wir können von Finnland oder den Niederlanden lernen – von ihren Bausystemen und Fügetechniken und umgekehrt. Diese Vernetzung ist meiner Meinung nach sehr wertvoll.

Welche Art von Auswirkungen wünschen Sie sich für das Projekt eines Tages? Glauben Sie, dass es nach Abschluss des Projekts einfacher sein wird, die Norm auf europäischer Ebene zu aktualisieren?

Auf deutscher Seite habe ich derzeit die Entwicklung einer deutschen Norm auf der Tagesordnung, aber dieser Prozess braucht Zeit. Er erstreckt sich in der Regel über mehrere Jahre, da eine Norm vor ihrer Veröffentlichung gründlich geprüft und Einwände von Experten berücksichtigt werden. Derzeit gilt, ein gebrauchtes Bauteil ist sowohl nach EU- als auch nach deutschem Recht ein nicht geregeltes Bauprodukt.

Wir werden nicht alle Probleme im ReCreate lösen können. Die Aufgaben sind sehr komplex und umfangreich. Durch unsere Forschung werden sich auch neue Fragen ergeben. Wichtig ist für mich, dass Regeln und Standards entwickelt werden, die den gesamten Prozess erleichtern. Das ist eine große Herausforderung. Wir möchten zum Beispiel eine Standardlösung zu Gewährleistungs- und Haftungsfragen für den Einsatz von gebrauchten Betonelementen – gemeinsam mit juristischer Expertise – entwickeln. Es ist ein Leitfaden zu erarbeiten, der aufzeigt, welcher Akteur für welche Leistung verantwortlich ist, welche Arbeitsschritte erfüllt werden müssen, um die Wiederverwendung effektiv zu planen und umzusetzen.

Die EU-Bauprodukteverordnung regelt den Marktzugang und die Verwendung von Bauprodukten. Die 16 Landesbauordnungen in Deutschland definieren die allgemeinen Anforderungen an bauliche Anlagen, die durch die Technischen Baubestimmungen konkretisiert werden.

Eine harmonisierte Spezifikation nach EU-Bestimmungen würde meiner Ansicht nach, dazu beitragen, der Wiederverwendung von gebrauchten Betonelementen mehr Aufmerksamkeit zu schenken. Bislang gibt es hierzu keine harmonisierte Bewertung bzw. Norm.

Vielleicht ist es also noch zu früh, denn es muss noch viel Forschung zu diesem Thema betrieben werden. Aber genau das ist die Aufgabe des ReCreate-Projekts: die notwendigen Forschungsergebnisse zu ermitteln und sie dann den politischen Entscheidungsträgern vorzulegen, damit diese sie in die Politik, in Vorschriften und Normen einfließen lassen können. Sind Sie damit einverstanden?

Ja, ich bin einverstanden. Das ist der nächste Schritt. Im ReCreate-Projekt schaffen wir wesentliche Grundlagen – mit wissenschaftlich fundierten Methoden untersetzt. Die erarbeiteten Lösungen werden sich in einer EU-Norm wiederfinden – erhoffe ich mir.

Ich schließe Interviews immer gerne mit der Frage ab: Wer ist Angelika Mettke und was macht sie gerne, wenn sie nicht gerade am ReCreate-Projekt oder an ihrer Hochschule arbeitet? Was sind ihre Lieblingsbeschäftigungen in ihrer Freizeit?

Ich verbringe gern Zeit mit meinen Enkelchen, bin gern in der Natur und in meinem Garten. Ich habe ein Haus und ein Wochenendgrundstück. Dort gibt es immer zu tun, und es macht mir Spaß. Es ist ein schöner Ausgleich, ein Kontrast zur Büro- und Denkarbeit. Ich kann mich an der frischen Luft bewegen, mit meinen Enkeln draußen spielen und gleichzeitig Tiere beobachten sowie das Singen der Vögel genießen. Gestern habe ich zum Beispiel einen Igel in unserem Garten beobachtet. Je älter ich werde, desto stärker nehme ich das Wunder Natur wahr. Deshalb ist es mir auch wichtig, dass die Natur und unser Lebensraum, unsere Landschaft erhalten bleibt und so wenig wie möglich gestört wird. Das deckt sich mit meinen eigentlichen Aufgaben und meinem Beruf: Ressourcen schonen, wenig bis nicht in die Natur eingreifen. Ich pflanze Blumen, Sträucher und Bäume. Ich weiß, dass ich in meinem kleinen Tätigkeitsgebiet etwas dazu beigetragen habe; gesellschaftlich Sinnvolles zu leisten Ich verbringe den Urlaub sehr gern an der Ostsee in Warnemünde und Kühlungsborn sowie in verschiedenen Orten auf der Insel Usedom und der Insel Rügen. Das Flair ist einzigartig. Mir ist aber auch bewusst, dass jedes Land schöne Orte hat.


January 15, 2025
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Arlind Dervishaj, KTH

Concrete is used everywhere—in buildings, cities, and infrastructures. However, due to the large quantities of concrete used worldwide, it contributes to around 8% of global CO2 emissions [1]. While efforts are being made to reduce its carbon footprint, such as by using supplementary cementitious materials, an often overlooked solution is reusing concrete.

The ReCreate project aims to foster a circular economy in the construction industry by reusing precast concrete elements from existing buildings in new construction projects. To support this goal, our study investigated the reuse potential of structural concrete elements, evaluating three key factors: the remaining lifespan of concrete, natural carbonation (ability to reabsorb CO2 over time), and embodied carbon savings achieved by reusing it [2]. Reusing concrete has multiple benefits as it prevents waste, reduces the need for new raw materials, and significantly lowers life cycle CO₂ emissions. However, it is not as straightforward as it looks. The structural integrity of concrete with reinforcing steel can be compromised over the lifetime of buildings, if the right conditions for corrosion emerge, such as from the carbonation of the concrete cover and the presence of moisture at the rebar interface [3].

Circular Construction concept for concrete

Based on established carbonation models, we proposed a digital approach for estimating the remaining service life of concrete elements. The digital workflow also estimates the CO2 uptake from natural carbonation. We tested the workflow on an apartment building with a precast concrete structure, built in Sweden in 1967 during the Million Program. The building was modelled digitally, and material quantities and exposed surface areas of concrete elements were automatically extracted.

Digital workflow and building model

A key aspect of the study was the comparison of carbonation rates specified in the European standard EN 16757:2022 with rates derived from measurements in the ReCreate project and the literature [4,5]. This comparison revealed that the carbonation rates in EN 16757 may be overly conservative and hinder the reuse of concrete elements. We argue that relying on contextual carbonation rates, such as the ones in our evaluation, from a previous condition assessment, and new on-site measurements, is crucial for making informed decisions about concrete reuse. The study also addresses the recent RILEM recommendation on revising carbonation rates in standards like EN 16757 and CEN/TR 17310:2019 [6]. 

Using carbonation rates from EN 16757:2022, led to the conclusion that most of the precast elements would not be reusable (i.e. carbonated concrete cover and past the initiation phase for service life). The standard assumes a high rate of carbonation for concrete, especially indoors, which reduced the concrete’s remaining service life; concrete cover for indoor elements was expected to carbonate the earliest, 23 years after initial construction. However, when using the contextual carbonation rates derived from the ReCreate project’s investigation and recent literature, all elements were deemed suitable for reuse, with sufficient remaining lifespan. Plaster and other coverings slowed carbonation significantly, extending the service life of concrete. Additionally, carbonated concrete elements can be reused, but further considerations should be made concerning the environment and exposure conditions in the new building. Recommendations from ongoing research in ReCreate are expected for concrete reuse in new buildings.

The study also assessed the CO2 uptake of concrete over its life cycle, including the first service life, a potential storage period prior to reuse, and a second service life when reusing precast elements. The findings indicate that the CO2 uptake estimated using the EN 16757 rates was significantly higher than the estimate based on contextual rates. Additionally, the study demonstrated that the climate benefits of reuse exceeded those of carbonation, which accounted for less than 6% compared to the emissions associated with the production and construction of new precast concrete buildings. This highlights the importance of prioritizing reuse as a key strategy for reducing the climate impact of buildings.

Furthermore, the study investigated the implications of three different allocation methods for assessing the embodied carbon of concrete over two life cycles. The analysis included scenarios with and without carbonation uptake. The results indicated that the Cut-Off method was the most advantageous for reusing the existing building stock, followed by the Distributed approach, while the End-of-Life approach was the least favorable. The study emphasizes that the reuse of existing building stock offers a substantial opportunity for mitigating climate change and fostering a circular built environment.

Comparison of three LCA allocations, over two life cycles

References

[1] Monteiro PJM, Miller SA, Horvath A. Towards sustainable concrete. Nat Mater 2017;16:698–9. https://doi.org/10.1038/nmat4930. 

[2] Dervishaj A, Malmqvist T, Silfwerbrand J, Gudmundsson K. A digital workflow for assessing lifespan, carbonation, and embodied carbon of reusing concrete in buildings. Journal of Building Engineering 2024;96:110536. https://doi.org/10.1016/j.jobe.2024.110536. 

[3] Angst U, Moro F, Geiker M, Kessler S, Beushausen H, Andrade C, et al. Corrosion of steel in carbonated concrete: mechanisms, practical experience, and research priorities – a critical review by RILEM TC 281-CCC. RILEM Technical Letters 2020;5:85–100. https://doi.org/10.21809/rilemtechlett.2020.127. 

[4] European Committee for Standardization (CEN). Sustainability of construction works – Environmental product declarations – Product Category Rules for concrete and concrete elements (EN 16757:2022) 2022. https://www.sis.se/en/produkter/construction-materials-and-building/construction-materials/concrete-and-concrete-products/ss-en-167572022/ (accessed November 26, 2023). 

[5] European Committee for Standardization (CEN). Carbonation and CO2 uptake in concrete (CEN/TR 17310:2019) 2019. https://www.sis.se/en/produkter/construction-materials-and-building/construction-materials/concrete-and-concrete-products/sis-centr-173102019/ (accessed September 26, 2022). 

[6] Bernal SA, Dhandapani Y, Elakneswaran Y, Gluth GJG, Gruyaert E, Juenger MCG, et al. Report of RILEM TC 281-CCC: A critical review of the standardised testing methods to determine carbonation resistance of concrete. Mater Struct 2024;57:173. https://doi.org/10.1617/s11527-024-02424-9.


November 22, 2024
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Jakob Fischer, Brandenburg University of Technology

As Europe strives to meet its sustainability targets, the construction industry’s environmental impact is under increasing scrutiny. The sector is responsible for a significant portion of Europe’s resource consumption and waste generation. A key solution lies in evaluating building stock for its potential to contribute to circular economy practices, particularly through the reuse of construction materials like prefabricated concrete components. By reducing waste and conserving resources, this approach can help achieve the European Union’s (EU) climate and sustainability goals.

Europe’s Sustainability Goals and the Construction Industry

The European Union has committed to several ambitious targets, primarily through the Sustainable Development Goals (SDGs), including Goal 9 (Industry, Innovation, and Infrastructure), Goal 11 (Sustainable Cities and Communities), and Goal 13 (Climate Action). These goals promote building resilient infrastructure, reducing waste in urban environments, and taking urgent action on climate change.

In parallel, European policies such as the Circular Economy Package, the EU Waste Hierarchy, and the European Green Deal aim to curb resource extraction and promote material reuse. The building construction industry, as one of the largest consumers of resources and generators of waste, is central to these efforts. By recovering reusable concrete elements from existing structures, the sector can reduce its carbon footprint and contribute to Europe’s climate neutrality goal by 2050. The ReCreate project is developing numerous implementations to achieve these contribution goals.

Assessing Building Stock for Reuse

Evaluating building stock involves analyzing existing structures to identify materials that can be reused in new construction projects. This is especially important as Europe’s built environment contains vast amounts of materials, particularly concrete, that can be repurposed instead of discarded. The work package 1 of the ReCreate project is developing an analysis and mapping of existing precast concrete systems and elements.

Prefabricated concrete components, which are common in many buildings, offer substantial potential for reuse. These modular elements can be removed, inspected, and repurposed in new projects, reducing the need for energy-intensive production of new materials. Since concrete production is responsible for a large share of carbon emissions, reusing elements as a whole can significantly lower the environmental impact of the construction industry. Emission reductions of up to 98 % in comparison to virgin material prefabricated concrete elements, can be saved by reusing existing elements.

Urban Mining and the Circular Economy

Urban mining is a key element in transitioning towards a circular economy, where resources are reused rather than discarded. Buildings, especially those built in the mid-20th century, contain prefabricated concrete components that are still in good condition and suitable for reuse. Rather than allowing these materials to become waste, urban mining enables their recovery, helping reduce construction and demolition waste (C&DW).

C&DW represents nearly 40% of the total waste produced in the EU, underscoring the pressing need for robust waste management strategies. By reusing concrete elements as a whole the construction industry can contribute to a significant reduction in CO2 emissions. With concrete production accounting for up to 8% of global carbon emissions, any reduction in its demand has a meaningful impact on climate change mitigation.

Overcoming Challenges in Building Stock Evaluation

While the reuse of building components offers significant sustainability benefits, several challenges remain. On the one hand the structural and architectural integrity of reusable concrete elements have been testified and is being proven within the ReCereate project, however no market for reused elements has been developed yet, which could satisfy the demand of sustainable re-construction. Hence, the working packages 1 and 6 with the deliverable 6.2 will give an overview of the distribution and amount of defined elements in the existing building stock.

Another challenge is to evaluate the needed information for exact types of elements in existing buildings from national building stock databases. With the support of building owners (e.g. providing information on their building stock), reviewing literature and archives on construction/production activities in the past and assessing the current and future demolition rate, a more accurate assessment of the building stock will be investigated.

A centralized database tracking reusable materials across Europe could further enhance urban mining efforts. By cataloging the types, quantities, and conditions of reusable components, such a system would allow construction companies to plan projects more efficiently, ensuring that recovered materials are utilized effectively. Parts of these efforts will be achieved within ReCreate.

Conclusion

The systematic evaluation of building stock and the adoption of urban mining practices can contribute significantly to Europe’s sustainability efforts. Reusing materials like concrete supports SDG 9 by promoting resource-efficient infrastructure. It also aligns with SDG 11 by reducing urban waste and improving resource management, while contributing to SDG 13 by helping reduce the carbon emissions associated with new construction.

Achieving this requires collaboration between policymakers, industry professionals, and researchers. Governments can implement the regulatory frameworks and incentives needed to make reuse the norm, while construction professionals must adopt new approaches that prioritize resource recovery. Also building owners should be sensitized, to regularly evaluate their building stock, keeping track of their own ‘urban mine’ and step forward to interested planners and stakeholder in the construction industry with their upcoming potential of deconstructable and reusable concrete elements.

The future of Europe’s construction industry is circular, and evaluating building stock is a key step in realizing this transformation.


August 9, 2024
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Tommi Halonen, project manager, City of Tampere, Finland

Sometimes I get asked: ‘Why is the City of Tampere participating in ReCreate, and what is our role in the project?’ It might be much easier to see why a university or a construction company is taking a part in a project where the goal is to (de)construct buildings in a novel way. But what is the city doing in ReCreate, especially when the deconstruction pilot was not a public building? From my viewpoint, cities have in particular the following two roles to play in the circular transformation:

Role 1: developing public processes that enable the implementation of CE solutions.

First, cities have a significant role as regulators in the construction industry. If there are any issues related to public regulation that do not allow reuse or make it extremely bureaucratic, it is impossible or very difficult (or expensive) to create business out of ReCreate or any other circular solution. There are especially two matters that are regulated by the city authorities that are worth paying attention to: (1) implications of waste legislation and (2) product approval practices.

(1) During the ReCreate project, we’ve had multi-stakeholder discourse in Finland about whether reused building parts should be considered as waste or not – some stakeholders opposed, and some supported the waste status. However, at the end, it is the city officers that control the matter and they needed to decide how to proceed with it. I cannot go through all the matters the authorities needed to consider in order to clarify the issue but in brief, the hardest part was to find a balance between environmental protection and excessive (too heavy) bureaucracy. Eventually the authorities were able to clarify their policies so that, in Finland, reused components are not considered as waste when certain pre-requisites are fulfilled. At the time of writing this blog, we’ve also received an official decision that ReCreate elements are not considered as waste. This is a huge development step in the Finnish industry towards circularity.

(2) Another matter the cities regulate is the product approval of reused building components. Unlike new products, the CE (conformité européenne) mark does not apply to reused products. In Finland, the products are approved as part of a so called ‘building site approval process’ that is regulated by the municipal building supervisors. There is no prior experience of the approval process. Consequently, the situation is now very similar to the aforementioned case: city authorities must again develop practices and policies that ensure that essential technical requirements are met when reusing components but are not too burdensome for practitioners to comply with. As I write this blog, we are in the process of discussing these practices with the authorities.

Role 2: creating needed incentives for companies for CE development.

Cities are not only passively enabling the circular transformation, but they can – and they must – actively initiate the change, too. Indeed, me and my colleagues have received feedback from multiple companies stating that due to early stage of the circular development, the industry cannot move to circularity solely with the help of market drivers and market logic. The companies emphasized the need for public initiatives that create incentives for circular development. Cities have at their disposal policy instrument that can create this market push. The most notable instruments are (1) public procurements and (2) plot handovers.

(1) During the project, we have had multiple meetings and workshops with the leaders of the city so that Tampere could incorporate reuse to future procurements and building projects. Sooner or later, reuse of building components will break through to public procurements and when it does, it will have a significant impact on the market.

(2) Another policy instrument that can initiate change is the plot handover process. In Finland, municipalities are the biggest landowners in urban areas. Traditionally, sustainability or circularity goals have not been part of the handover processes. However, in 2022 the City of Tampere initiated an all-time first circular plot competition. It was a success with nearly 20 building proposals and applications and received a lot of positive attention in general as well as in professional media. Many cities got inspired and wanted to repeat the circular competition. What we decided to do with my colleagues was to launch a working group, the goal of which was to create upgraded and unified circular criteria for the municipalities. Around 30 experts worked on the criteria for a year, and after receiving feedback in different workshops and seminars, we were able publicize the criteria at the beginning of this year. Now, we are keen to see the impact that the criteria will create when the cities are starting to include them to their plot handovers and competitions.

All in all, while this blog is not an exhaustive list of all the role the cities have in the circular transformation, I do hope that I was able make the case that cities are one of the major players enabling the transition. Indeed, for me personally, it is very difficult to see how the industry could make the transition to the circular economy on a large scale if the cities are not developing public policies and processes to promote circularity.

 


June 20, 2024
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Antti Lantta, project manager (building demolition), Umacon & Juha Rämö, technology director, Consolis Parma

The earth’s carrying capacity is being tested, and it cannot sustain the growing use of virgin natural resources on the scale required by the current economic and population growth. The most acute environmental damage of our time results from global warming and the loss of biodiversity.

The built environment is of great importance for an ecologically sustainable society, as the construction sector globally consumes about half of all the world’s raw materials and causes about a third of greenhouse gas emissions. From the perspective of a circular economy, there is a huge potential here.

This includes the EU-funded four-year international research project ReCreate (Reusing prefabricated concrete for a circular economy), which studies the reuse of concrete elements, which are deconstructed from buildings slated for demolition, in new construction. Umacon, a top demolition expert, and Consolis Parma, Finland’s leading manufacturer of precast concrete elements, are also involved in the research project.

Umacon renews demolition industry in Finland

The prevailing demolition method in Finland focuses on material recovery, where the secondary raw material materials created through demolition are used in the recycled or otherwise utilized, for example in earthworks. Reusing whole precast concrete elements is rare, even though valuable building parts and equipment, such as building services components, industrial machinery and steel or wooden columns and beams, have been salvaged in Finland in the past. Until now, deconstruction has been driven more by the resale value of building components and equipment than the goal to reduce carbon dioxide emissions.

The reuse of precast concrete elements has not been implemented on a larger scale in Finland before. For Umacon, environmentally friendly and sustainable construction is part of its business values, so applying for the ReCreate research project was a natural choice. The work phases of the deconstruction project had to be planned in a new way so that the elements would not be damaged during the deconstruction work. During the project, new working methods and methods for detaching and lifting elements were developed to ensure that the deconstruction takes place safely and efficiently. Efficient working methods were refined as the project progressed. For example, it took four weeks to deconstruct the elements of the topmost floor, but the last floor was completed in just five working days! The key to a successful project was combining an array of different working methods that had been tried and tested in previous demolition projects into a functional deconstruction process.

Umacon wants to renew the demolition industry in Finland and become a leading company in the deconstruction sector. The success of the ReCreate research project shows that deconstructing precast concrete elements as intact is technically possible. By steering legislation towards low-carbon construction and improving the productivity of deconstruction, deconstruction will mainstream in Finland. Deconstruction and construction are teamwork that require the cooperation of all parties to achieve the goals.

New business for element manufacturer Consolis Parma

Consolis Group is committed to the targets set out in the Science Based Targets initiative. The Group’s global goal is to achieve zero emissions by 2050. The Finnish Consolis company Parma aims to reduce emissions by five per cent annually and halve them by 2035. The most significant means for reducing emissions are the increased use of low-carbon concrete elements, energy efficiency, and the circular economy.

Parma’s low-carbon products are based on substituting cement with binders from industrial side streams. In addition, crushed concrete is utilised in place of virgin aggregates. In the future, one possibility is to supply fully recyclable elements alongside new low-carbon concrete elements.

In the ReCreate research project, the reuse of whole elements is focused on in real life. The elements salvaged from the donor building in Tampere have been delivered to Parma’s Kangasala factory, where they undergo a quality check as well as the necessary modifications and equipment for reuse. The elements that have now been reclaimed were originally manufactured at the company’s factory in Ylöjärvi, Finland, and thus Parma is involved in a research project to promote the reuse of the elements it has manufactured itself.

In this kind of new business, the role of an element manufacturer may include, for example, design, quality control, dimensional changes and equipment, as well as other functions that are suitable to perform alongside new production at the precast concrete factory. Issues to be studied that deviate from new production include approvals, processes and logistics (deconstruction of elements, transfer to the factory, factory-refurbishment measures, transfer of elements to a new site and installation of elements) and environmental permit practices.


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Tove Malmqvist Stigell, Senior Researcher and Docent, KTH Royal Institute of Technology 

A transition towards a more circular economy is currently lined up by multiple ongoing policy processes, not least within the EU Green Deal. One novel regulatory development already in effect in a few European countries is mandatory climate declarations and limit values on GHG emissions for buildings. What are these regulations and how do they connect to the re-use of precast concrete elements?

After several decades of development of LCA (Life cycle assessment) methodology for buildings aiming at guiding low-impact design in a life cycle perspective, a raised interest for building LCA has been seen during the latest years. Not least insights on the significance of embodied greenhouse gas emissions in buildings, has led to LCA-based regulations being introduced in several European countries. These require mandatory climate declarations of, so far primarily, new-build projects, and some of them also require building projects to display emissions below a set limit value. Such a climate declaration is a quantitative assessment of life-cycle related greenhouse gas emissions (GHG) of the building that the developer has to perform and hand in to the authority. Countries such as France, Sweden, Denmark and Norway already have such regulations in effect since 2022-2023. In France and Denmark limit values for these emissions are part of the regulation. Such limit values are represented by a set number of kg CO2-equivalents per floor area or per floor area and year, which can be tightened over the years to support further GHG emission reduction. Such limit values are also planned to be introduced in the coming years in Sweden and Finland. The Netherlands introduced a more comprehensive LCA-based declaration with limit value already in 2017. At EU level, the recast of the EPBD (Energy performance of buildings directive) requires a mandatory climate declaration for new-build from 2027 for buildings over 2000 m2 and from 2030 for all buildings, and similarly the EU taxonomy stipulates such a declaration from 2023 for buildings over 5000 m2. 

In the light of this type of regulatory development, the interest for developing methods to implement re-use of building components in new-build has increased much. The reason for this is that reuse of components could be one, among other strategies, to ensure low-carbon designs and to comply with tougher limit values in similar regulations. This since re-used components in general have lower environmental impact than virgin ones. To incentivize such strategies further, the Swedish regulation, as an example, makes it possible for a developer to use re-used products “for free”, that is count them as zero impact in the stipulated climate declaration. When setting up the mandatory climate declaration, the Swedish regulation requires a developer to make us of generic data from the national climate data base of Boverket unless EPD´s (environmental product declaration) exist and are used (and also verified that these products were procured to the building at stake). Reused construction products in Boverkets database are however currently allocated zero GHG emissions, thus incentivizing reused products in new building design This is naturally a simplification for to create an incentive, but since EPD´s on re-used building components are still extremely rare it would in the current situation not benefit re-use of precast concrete elements to require more detailed information on e.g the emissions of the reconditioning processes. Meanwhile, this type of information is currently built up in the ReCreate project based on the demonstrators in the project. 

A central issue of significance in the design of building LCA studies, including the method of LCA-based regulations, is the coverage of processes, that is the system boundaries for the assessments. It is often necessary to omit certain processes due to lack of data or to focus the assessments on known hot-spots. When these types of assessments now enter regulation, different countries take slightly different approaches to the choice of system boundaries which has led to discussions regarding how they then incentivize, or not,  certain low-carbon strategies such as circular solutions. For example, the Swedish regulation focus the production and construction stage impacts, that is the embodied GHG emissions of modules A1-A5, according to the European standard EN 15978. In a life cycle perspective, these emissions constitute a significant, and earlier non-regulated, hot-spot. These emissions can also be verified by the completion of a building project, compared to emissions associated with the use and end-of-life stages of buildings. Principally, one could argue that such a more narrow system boundary increase the incentives for re-use of precast concrete elements since the emissions of modules A1-A5 in contemporary construction of buildings are much dominated by the materials of the structure. If implementing more of a whole-life system boundary, as for example is planned for in Finland, the proportional impact of modules A1-A5 will be less, which might reduce the incentivizing effect of re-using building components. 

A well-known obstacle to reuse today is the difficulty, and thus the high costs, of dismantling buildings for reuse of elements and components with a viable service life left. This is a question that often comes up in connection to building LCA, with the idea that including the end-of-life (module C) and benefits and loads beyond the system boundary (module D) in the assessment system boundary would incentivize measures taken for design for re-use, including design for disassembly (DfD). However, end-of-life emissions associated with pre-cast concrete elements are much lower compared to emissions associated with the production stages (modules A1-A3) of contemporary construction in the European context, and it may thus be questioned to what extent it´s inclusion could have an incentivizing effect.  

An aim with module D is to give room for displaying future potential benefits in form of emission savings due to e.g reuse of components in new constructions, to be reported separately according to the EN 15978 standard. It should be noted that module D highlights potential future savings, the extent of which depend on the future handling of the components, which is hard to predict. The prospects for future re-use improve with DfD implemented, but the calculation of module D is not linked to whether such design strategies were implemented or not. Finally, one needs to remember that both module C and D deals with assessment of potential emissions in a distant future, thus their assessment becomes very uncertain. Normally, these assessments reflect today´s technology, but an increasing number of voices promote that decarbonization scenarios should be applied in similar long-term assessments. If so, the significance of module C and D also decrease. 

The proposed Finnish regulation is an example of a more comprehensive system boundary. It for example introduces thecarbon handprint which more or less reflect an assessment of module D to, in quantitative terms, visualize potential future benefits of re-using the components of the studied building along with other potential benefits of implemented design strategies

So to sum up, the emerging climate declaration regulations in various European countries do create new incentives to apply re-use of prefabricated concrete elements in today´s new-build. However, to for increased implementation of DfD strategies in today´s new-build for improving prospects for future re-use, these types of regulation do not provide direct and clear incentives. Instead, complementary steering mechanisms might be needed to promote DfD strategies

Resources: 

Boverket climate database in Sweden: https://www.boverket.se/sv/klimatdeklaration/klimatdatabas/  

Finnish emissions database for construction: https://co2data.fi/rakentaminen/#en   

Example of proposed ongoing regulatory development: the next steps proposed for the Swedish climate declaration regulation: https://www.boverket.se/en/start/publications/publications/2023/limit-values-for-climate-impact-from-buildings/#:~:text=Limit%20values%20can%20be%20introduced,on%20climate%20declarations%20for%20buildings  


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In this exclusive interview, we delve into the pioneering work of Patrick Teuffel, founder of CIRCULAR STRUCTURAL DESIGN, as he leads the charge in revolutionizing structural design for a circular economy. With a focus on sustainability and decarbonization, Teuffel discusses his role in the ReCreate project, shedding light on innovative approaches to integrating reclaimed precast concrete elements into new constructions. From reimagining design processes to the challenges and benefits of incorporating AI, Teuffel provides invaluable insights into shaping a more environmentally responsible future in construction.

1. Can you please introduce yourself a bit, your organization and your role in the project?

As founder of CIRCULAR STRUCTURAL DESIGN, I am strongly focused on advancing the principles of the circular economy and decarbonization within the built environment in the context of structural design. With my background as a structural engineer, I bring a strong combination of technical expertise and sustainability principles to my work. As an academic as well as professional, I am committed to revolutionizing traditional construction practices by integrating circularity and sustainability into every aspect of the design process.

In addition to my entrepreneurial pursuits, I also act as a professor specializing in Innovation and Sustainability Strategies at SRH Berlin School of Technology. In this role, I have the opportunity to impart my knowledge and passion for creating more environmentally responsible solutions to future generations of professionals. My advisory role at the DGNB (German Sustainable Building Council) Innovation Board and the circular construction team at Circular Berlin further underscores my dedication to driving meaningful change within the industry.

At CIRCULAR STRUCTURAL DESIGN, our mission is to seamlessly integrate the principles of circular economy and sustainable design into every structural project we undertake. Our approach is guided by three core principles:

1.) Minimizing waste and emissions: We prioritize minimizing resource consumption and emissions associated with our structures, ensuring that our designs have minimal environmental impact.

2.) Keeping products and materials in use: Our commitment to extending the lifecycle of materials, components and buildings drives us to promote high-level reuse and repurposing wherever feasible, thus reducing resource consumption and waste generation.

3.) Using renewable resources: In response to the ongoing depletion of finite resources, we actively explore and incorporate renewable material options whenever possible.

It is our mission to bridge the gap between research and practice and to integrate the principles of circular economy into everyday structural design projects.

Within the ReCreate project I am the lead of the WP5 that explores aspects of redesign and reassembly. I, as a structural engineer, focus on the implications for the design process and the actual technical and practical implementation in the context of the reuse of existing components.

2. Can you provide more information on your work package and how it contributes toward the project?

WP5 consists of two parts: redesign and reassembly. We explore design implications of the stock-based design and develop new connection types or put existing connections to the test to reconnect existing precast concrete elements.

Traditionally the design process follows a linear model. The building design is developed first and the required structural elements, that are needed to accomplish this design, will be manufactured from scratch according to the dimensions required for the project.
The whole work process needs to be rethought when it comes to reusing elements. When maximizing the integration of reused elements in a stock-based design approach, the traditional design approach of form-follows-function will be replaced by a new principle: form-follows-availability.

To enable the load-bearing reuse of existing components, connection details are required with which these can be reconnected. This is why the documentation of connection details that already exist and allow for an easy reuse and developing new connection details that will also allow for an easier future disassembly are the second focus point in WP5.

Perhaps the most interesting thing about the ReCreate project is, that these approaches are not only theoretically explored, but will be implemented in real live pilot projects. Hence a large part of WP5 is designing those pilots and sharing the lessons learned throughout the process.

3. Tell us more about task 5.1 on the framework of parameters for the development of the redesign and reassembly process for precast concrete elements in new buildings?

As stated, the design process is completely different from the status quo, when it comes to the integration of reclaimed elements. Here, the first step is to capture relevant information about the reclaimed precast concrete elements in order to know where and how those may be reused. So, the first thing you need to know is what those elements are. In task 5.1 we explore, what parameters and object properties need to be gathered and at what design stage different information needs to be available to enable architectural and structural design. Here, we are looking at typological and dimensional information and the structural capacity of the different elements.
This task closely interacts with other working packages, such as WP1: the analysis of precast concrete systems, WP2: the deconstruction as we are strongly interested in the shape and capability of each element after deconstruction, WP3: the logistics and processing and WP4: the quality management.

The knowledge gained through this process will be captured in a design guideline (deliverable 5.1) at the end of the project.

4. How does Task 5.3 highlight the challenges and complexities faced in the architectural and structural design process when reusing precast concrete elements?

Task 5.3’s focus is the understanding and developing of a design approach and actively implementing it in the design process in the pilot projects. The traditional approach of an architect developing a space concept first and an engineer designing the structural elements afterword to erect this space does not work when the pool of existing elements limits what they might be used for. Means: the design process needs to run “in reverse”. To understand the capability of the existing elements and what uses they can be put to, requires a close interaction of architects and engineers from the very beginning of the project.
Each country cluster approaches this separately and faces different architectural and structural challenges. Those experiences are discussed within the ReCreate project team and the experiences will be summarized in the form of a best-practice recommendation that incorporates the lessons learned from the project.

5. How does Task 5.3 propose to incorporate artificial intelligence (AI) and neural networks into the design process? What benefits are expected from using AI in this context?

When it comes to designing with reclaimed elements, different design approaches can be explored and different country clusters follow different approaches of how to start with a stock of reclaimed, prefabricated concrete elements and get to the finished product:  a building partially designed from those elements.
That insights gained and lessons learned will be gathered in a design manual that will be published as D5.1 at the end of the project.

Generally, the most straight-forward approach to designing with precast concrete elements is trial- and-error.

The larger the implicit knowledge about the reclaimed elements and reuse options are, the better the outcome will be.

Another possibility is a design optimisation aided by parametric design tools. Within the project research is undertaken how the design process can be aided by existing and newly developed design tools that allow for an optimisation.

Also, an AI-aided element matching between a pool of existing elements and a proposed new design will be explored. Especially when the list of reclaimed elements is very large, human trial-and-error can reach its limits. The AI-aided approach tries to do a first step by exploring a matching algorithm that highlights optimisation potential and best matches.

6. Can you tell us more on the processes and challenges that you are facing with the connections in task 5.2 and how do they influence the rest of your work? What are some of the risks that are present here? In the context of design for disassembly (DfD), how does Task 5.2 investigate the possibility of easier deconstructability in the new connections?

The feasibility and ease of new structural connections construction for reclaimed element has a large impact of the likelihood integration of reuse structural elements. In WP5 options to reconnect those structural elements will be explored. Particular attention is paid here to when the same connection points can be reused (with minor adjustments) during reinstallation. The connections that are to be used in the construction of the pilot projects are described. New connection types are also being developed in the project, those put a great emphasis on the possibility for a simple future deconstruction.
The general approach in the recreate project is, that both, new connection details that allow for an easier future disassembly are being developed in project funded university research studies. At the same time in the real life pilot projects conventional connection details that already exist, might also be used.

7. What is the relationship between the re-use of precast concrete elements and sustainability certificates, such as DGNB as discussed in Task 5.3?

When it comes to evaluating the sustainability of the reuse of precast concrete elements from an ecological viewpoint, two aspects can be highlighted. The reuse may help to save both finite resources and avoid new production emissions.
The topic of resource conservation in the context of a circular economy has recently come increasingly into focus, and green building certificates are trying to account for it. One example is here the the DGNB, where I am a member of the committee for lifecycle and circular design, the “DGNB Ausschuss für Lebenszyklus und zirkuläres Bauen“.

Important aspects such as reuse and deconstructability, which are addressed within WP5, are discussed here.

Additionally, a buildings carbon footprint is of course an important aspect to consider when it comes to evaluate the overall sustainability. Within WP5 internal meetings, the use of “LCA-as-a-Design-Tool” is repeatedly addressed. The goal is to actively identify and prioritize the lowest-emission design variant through regular design-integrated LCA (Life Cycle Assessment). Here we also closely collaborate with WP6.

8. How does Task 5.4 ensure a smooth implementation of the four real-life pilot projects, considering factors like transportation, supplementary materials, and equipment?

Let’s have another interview next year, then we can answer this question 😊

9. Who is Patrick Teuffel when he’s not working on the project and what does he like to do in his free time?

As for my personal preferences, I thoroughly enjoy engaging in sports like running and mountain biking, finding exhilaration in the great outdoors. Additionally, I have a passion for savoring good food, particularly exploring diverse culinary experiences. Living in the vibrant city of Berlin, I find immense pleasure in attending concerts and immersing myself in its dynamic cultural scene. Furthermore, I have a strong interest for exploration, fueled by my love for traveling and exploring the world, seeking out new adventures and experiences wherever I go. Last, but not least, I’m doing the final editing of this text in a spa – now you know where you can find me on a Sunday afternoon.


January 31, 2024
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Toni Tuomola, District Manager, Skanska (Finland)

Skanska’s role in ReCreate is strongly linked to its goal of building a better society. Being climate-smart – one of our sustainability themes – supports the achievement of this goal. Within the ReCreate project, we are studying how to produce low-carbon solutions through our business operations. ReCreate will provide us with information on how the circular economy of building elements could be promoted in the future – for example, in the planning phases of construction projects. We can have a major influence over the carbon footprint of a project’s outcome, especially in in-house development projects and, above all, in projects where we are responsible for the design.

ReCreate’s Finnish deconstruction pilot site is a 1980s office building in the city of Tampere. The precast concrete frame has been dismantled using a new technique developed and studied as part of the project. Construction projects are complex entities that demand close cooperation to meet targets. We have already worked with the ReCreate project partners for a couple of years on studies and advance preparations to facilitate the practical deconstruction work. Thanks to the studies, we were capable of dismantling the precast concrete elements intact for reuse. We also know how to verify the properties of reusable elements reliably and cost-effectively.

The possibility of technical implementation alone is not enough

 

Creating a business ecosystem for reusing building elements is an important part of the project. Reuse requires off-site production plants for factory refurbishment and the creation of an entire logistics chain and information management process to put the elements to use again. A marketplace is also needed to bring product providers and users together. Barriers must be lowered in building regulations and practices, and operating models must be harmonized.

What are the implications if reuse is successful? Firstly, the environmental benefits will be significant because the carbon footprint of reused concrete elements is about 95% smaller than that of corresponding new elements. Therefore, it will be possible to realize a substantial decrease in the carbon footprint of new buildings. Reused elements may not necessarily be used to construct entire buildings, but they would be utilized in the most suitable places. This would ensure that the dimensional and strength properties of reused elements can be used to the best effect.

The reduction in the carbon footprint helps us to meet the low-carbon requirements that will be introduced through regulation in the future. Environmental certification programs such as LEED and BREEAM also award extra points for reusing building materials.

Decommissioning a building by deconstructing elements is slower and more expensive than conventional destructive demolition. However, prior international research has found that a reused element can be as little as 30% of the price of a new element. This is an important perspective for projects researching business opportunities based on the circular economy.

A climate-neutral society is the sum of many parts, large and small. The circular economy of precast concrete elements is one factor among many. We need all the parts to work together to reach this goal.





EU FUNDING

“This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 958200”.

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