Circular economy - Recreate

January 15, 2025

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.

by ReCreate project

November 22, 2024

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.

by ReCreate project

August 9, 2024

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.

by ReCreate project

June 20, 2024

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.

by ReCreate project

May 17, 2024

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). Re–used 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 re–use 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 the “carbon 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

by ReCreate project

May 10, 2024

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.

by ReCreate project

January 31, 2024

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.