reuse - Recreate

December 10, 2024
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As part of the ReCreate project, WP7 plays a pivotal role in developing circular business models for concrete reuse, contributing to the overall goal of establishing sustainable and economically viable practices in the construction industry. In this interview, key team members from Tampere University—Leena Aarikka-Stenroos, Mikko Sairanen, Linnea Harala, and Lauri Alkki—share updates on their progress, insights into co-creating business models, and the value propositions they’ve explored for expanding the reuse business across Europe.

Can you share some updates on what WP7 has achieved so far within the ReCreate project?

LEENA: Absolutely! We’ve hit two important milestones. First, we’ve mapped out how different countries approach the reuse of building materials, focusing on three specific cases. This has helped us understand how actors in the construction industry are involved in reusing concrete elements. Second, we’ve started developing business models that show how companies can profit from reusing concrete. Moving forward, we aim to keep refining our understanding of how these processes work across different countries to ensure the project’s success.

WP7 focuses on developing circular business models at both company and value chain levels. Can you explain how these business models are being co-created and how they contribute to the project’s goals?

MIKKO: We’ve created business model canvases to map out how companies can profitably reuse concrete. These canvases cover three levels: the overall system, individual company profiles, and specific process stages like quality control or storage. Different countries have slightly different setups. For instance, in Germany and the Netherlands, some companies manage most process stages from deconstruction to reconstruction, while in other countries, multiple companies handle different parts of the process. By analyzing and mapping these models, we help companies figure out how to make this approach profitable, both in the short and long term.

LEENA: I’d like to add that we’ve noticed a lot of variation in how these models work across different countries. Some companies only handle deconstruction, while others do both deconstruction and reconstruction, which affects their business approach. This diversity helps us understand how different roles and processes can be profitable.

Could you share some insights into the value propositions, value creation, and value capture strategies explored within WP7 for concrete reuse?

LINNEA: We found several ways that reusing building components can create value, either through cost savings or new revenue. Key factors include the design and condition of the donor building, location, logistics, and efficient project management. Regulations and industry acceptance of circular practices also play a big role in creating value.

LAURI: In the Netherlands, we saw that “one-on-one” reuse, where components are taken from one building and directly used in another, is the most profitable approach at the moment, but of course it requires a key actor who can take responsibility along the process from deconstruction to construction. Overall, in all pilot projects companies also gained new skills, especially in deconstruction and design, which are critical to enabling component reuse.

MIKKO: In Finland, making concrete reuse profitable is a challenge, especially due to high deconstruction labour costs. Success depends on strong regulations, efficient demand management, and clear strategies for reuse. The Netherlands and Germany are good examples of how to do this effectively.

LEENA: Learning is key. Companies may face higher costs at first, but as they gain experience in deconstruction and reuse, they become faster and more efficient, lowering costs in the long run.

One of WP7’s objectives is to identify strategies to expand the reuse business across Europe. Can you explain these strategies and how they deal with the local nature of the building industry?

LINNEA: We’ve considered the idea of creating a marketplace for concrete elements, which could help expand reuse. However, there are challenges in making this work locally and deciding who would manage and profit from it.

LEENA: Construction companies often work in different countries, and they can apply what they learn in one place to another. For example, a Finnish company in our project wants to use its new practices across all the countries they operate in. However, different countries interpret regulations differently, which can be a challenge.

LAURI: That’s a great point, especially since we have large companies like Skanska and Ramboll in the project. Sharing knowledge between countries is key, and some countries offer great examples for others to learn from.

How does the analysis of safety and health aspects translate into economic value within the concrete reuse ecosystem, and what measures are being considered to enhance safety and health in this context?

LEENA: Safety and health analysis is crucial but incurs costs, such as for quality checks and safe practices. We need efficient ways to integrate these assessments, potentially using digital technologies, to minimize expenses while ensuring safety, which is vital for economic value in concrete reuse.

LAURI: In our discussions with Skanska, safety concerns about reused concrete elements were prominent. It’s essential to communicate to customers that these elements are thoroughly tested and safe to build trust in the market.MIKKO: Brand reputation in construction hinges on safety and quality. Companies must meet these expectations to protect their image, making quality a critical aspect of our analysis.

LINNEA: Work safety regulations can vary, affecting project costs and feasibility. For instance, Germany has stricter safety standards compared to Finland, impacting deconstruction costs.

Can you elaborate on the connections between social and legal barriers and economic value within the concrete reuse business models?

MIKKO: Social challenges, like public trust in reused concrete, can influence demand and economic value. Legal barriers, such as product compliance and market access issues, also affect economic viability. Balancing these factors is essential for successful business models.

LEENA: The Finnish Ministry of Environment values expertise in creating supportive regulations for circular processes, aligning with our project’s goals to shape favourable EU and national legislation for component reuse.

LAURI: In Finland, there’s confusion over classifying deconstructed elements as waste or not, which complicates handling and permits. This uncertainty has caused delays in the pilot project.

LINNEA: Ownership of elements is vital; in Finland, construction companies retain ownership from harvesting to sale, simplifying the process.

How do you envision the role of technology, societal acceptance, and regulatory factors in shaping the economic aspects of concrete reuse, as discussed in Task 7.4?

LEENA: Technology, societal acceptance, and regulatory factors are interconnected in influencing concrete reuse economics. Advancements like automation and digital modelling enhance feasibility and efficiency. Societal trust in reused materials boosts demand, while balanced regulations are needed to support innovation without hindering business. Effective communication and marketing can foster societal acceptance, helping to increase demand for reused concrete elements.

WP7 focuses on identifying easily achievable improvements and economic benefits in concrete reuse. What are some of the “low-hanging fruits” that have been identified, and how can they accelerate the transition toward more sustainable building construction?

LEENA: We’re identifying simple improvements, or “low-hanging fruits”, that can promote concrete reuse. While still gathering data, we see that small changes can encourage companies to embrace reuse without a complete overhaul.

LAURI: A key improvement involves rethinking collaboration roles in construction. Embracing broader collaboration beyond traditional roles can significantly enhance concrete reuse efforts.

MIKKO: Effective data management and communication among all parties are crucial. Knowing where deconstructed elements will be reused and planning accordingly can optimize the entire process.

In your journey with the ReCreate project, could you share a memorable experience or moment that has had a significant impact on your perspective or approach to sustainable construction and circular economy initiatives?

LINNEA: As a doctoral researcher, my most impactful experience was visiting the German cluster, where I saw how cost-effective building component reuse transformed old elements into new spaces. It was enlightening.

LEENA: A key moment for me was realizing the potential of concrete reuse in reducing emissions and seeing the project’s problem-solving spirit that drives sustainable improvements.

MIKKO: Visiting Lagemaat in the Netherlands was eye-opening; seeing their profitable concrete reuse operations changed my perspective on feasibility in this area.

LAURI: My memorable moments include witnessing the Lagemaat operations and the progress of our Finnish pilot project, both highlighting the project’s impact.

In summary, WP7’s efforts within the ReCreate project are forging a path toward a more sustainable and economically viable construction industry through the development of circular business models for concrete reuse. The insights gained from diverse country analyses, coupled with innovative strategies for collaboration and technology integration, underscore the potential for significant advancements in this field. By addressing safety, social acceptance, and regulatory challenges, the team is not only enhancing the viability of reused concrete but also building a robust framework for future circular practices. As these initiatives continue to evolve, they hold the promise of transforming the construction landscape across Europe, making it more resilient and environmentally responsible.


October 18, 2024
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Arnaldur Bragi Jakobsson

Second Wind explores the potential of reusing pre-cast concrete elements from an obsolete apartment building in Helsingborg, Skåne County, Sweden.

As part of the ReCreate initiative, which encourages the sustainable repurposing of concrete components, I collaborated with Helsingborgshem, the city’s municipal housing company, to develop a new rowhouse typology of approximately 100 m², alongside a two-story multifamily apartment building on the same plot.
The project aimed to minimize modifications to the existing structural components, preserving their original form as much as possible while adapting them to new uses. The rowhouses, arranged in an L-shape with a southwest-facing courtyard, serve as rental units and highlight the potential of reused materials in creating modern, functional spaces. The apartment buildings, located on the north and south sides of the site, further demonstrate the versatility of these repurposed elements.

 

Throughout this process, I sought to maintain a connection to the original architectural context of the Drottninghög area, respecting its mid-20th-century character while introducing new, sustainable housing solutions. This project illustrates the significant environmental benefits and creative opportunities in reusing existing building materials, paving the way for more sustainable construction practices.

 

Rowhouse plan (Arnaldur Bragi Jakobsson)


August 30, 2024
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Lina Brülls, Graduate Architect and Master’s Student in the Computer Science Program at Chalmers University of Technology

The master’s thesis “Resource-Driven Design” explores how the design process can be adapted to facilitate the reuse of structural concrete elements. Research done in the thesis indicates that current design and data processes are not easily translatable to reuse scenarios, where preexisting structural and geometrical attributes of materials must be considered. Based on this, three key research questions are formulated: identifying the necessary data for the reuse design process, developing a Grasshopper Rhino plugin for data integration, and applying this tool in case projects with the aim of optimising reuse.

The developed Grasshopper plugin, programmed in C#, enables data handling from Excel into Rhino. It generates structural modules from reused hollow-core and load-bearing wall elements based on desired design parameters. The tool was tested in three architectural projects on Siriusgatan in Bergsjön. Regular consultations with the ReCreate team at KTH provided helpful expertise and feedback throughout the development process.

The study’s findings suggest that integrating data early in the design process can improve the efficiency and feasibility of reusing structural elements. One key challenge encountered in this project was planning within the constraints of the generated load-bearing modules. Including glulam beams introduced necessary flexibility, enabling adjustments in level height and allowing the removal of some load-bearing wall elements.


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 12, 2024
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In June 2024, the ReCreate project reached significant milestones with two pivotal meetings held in Zagreb, Croatia. Hosted by GBC Croatia, these gatherings brought together partners, and experts to discuss progress, share insights, and plan future actions in our mission to revolutionize the construction industry through sustainable practices.

Consortium Meeting: 5th June 2024

The consortium meeting on the 5th of June was a vibrant assembly of all project partners. The event provided a platform for members to review the project’s achievements, address challenges, and align on upcoming objectives.

Highlights of the consortium meeting included:

  • Project Progress Updates: Each partner presented detailed updates on their contributions and advancements, showcasing the collective progress made since the last gathering. The emphasis was on the general status of the project management, communication and dissemination activities, and the status of the each project pilot.
  • Technical Discussions: In-depth discussions were held on the latest innovations in reusing precast concrete elements, highlighting technical challenges and solutions of each project pilot in Sweden, Finland, The Netherlands, and Germany.
  • Collaborative Workshop: Interactive workshop fostered collaboration among partners, focusing on differences, as well as advantages and disadvantages in centralized and decentralized pilot approaches.
  • Future Planning: During the meeting, partners outlined the next phases of the project, setting clear goals and timelines to ensure continued momentum and success.

Review Meeting: 7th June 2024

Following the consortium meeting, the review meeting on the 7th of June brought together WP leaders and external reviewers. This critical session aimed to evaluate the project’s progress against its objectives and deliverables.

Key aspects of the review meeting included:

  • An assessment of the project’s achievements to date, including a detailed examination of technical milestones and deliverables.
  • External reviewer Helena Granados Menéndez provided valuable feedback, highlighting strengths and offering recommendations for improvement to ensure the project’s success.
  • Discussions focused on the broader impact of the project on the construction industry and sustainability practices, emphasizing the importance of innovative solutions in real-world applications.
  • The meeting concluded with a clear roadmap for the upcoming months, emphasizing continued collaboration, innovation, and dissemination of results.

Both meetings were instrumental in driving the ReCreate project forward, reinforcing the commitment of all partners to transforming the construction industry through sustainable practices. We look forward to the next phases of the project with renewed energy and focus.

Stay tuned for more updates on our journey towards more sustainable future in construction.


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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  


March 15, 2024
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Inari Weijo, business development manager (refurbishment), Ramboll Finland

During my master’s thesis work over 15 years ago, I familiarised myself with precast production and its history in Finland. After that, precast concrete has been playing a role in one way or another in my work career. Many projects have involved either repairing precast concrete buildings or building new ones. Since the 1970’s, precast concrete production has formed a significant part of the Finnish construction sector. The systematic and ‘simple’ method provided a standardized way to build, and it quickly became very widespread. The precast concrete system has been criticized for producing a unified stock of buildings, reducing versatility in urban environment and suppressing designers’ creativity. Since the early days, though, the technique spread to erecting ever more complex and monumental buildings. It has been foundational for providing a fast and trusted way for building construction in Finland. There are thousands and thousands of precast concrete buildings here, and some of them are already slated for demolition. A part of the buildings suffers from degradation, but many are just mislocated from today’s point of view.

Figure 1. Finnish deconstruction pilot in Tampere, building vacated before the deconstruction of elements for reuse.

I believe that technical know-how is essential for creativity and enables responsible and sustainable construction. We must be more aware of our decisions’ environmental impacts when building new. Architects’ and engineers’ creativity is ever more challenged as we must prioritize sustainability values. Knowing the technical limitations and possibilities is crucial, so that creativity can be unleashed in the right place at the right time, and adverse uncertainties can be eliminated. Building new is inevitable in the future too, but we need to redefine ‘new’. We must apply regenerative thinking, create net positive solutions and aim for more ambitious circularity. The actions we undertake should have a positive impact on nature and the environment so that instead of consuming it, they restore and revive it. This is a leading value for Ramboll.

Figure 2. Regenerative approach to construction. Image source: Ramboll.

The prevalence of precast technology and the aim for a regenerative effect on environment are two leading thoughts that that drive our ambition here at Ramboll to examine and challenge the present business as usual in the construction sector. The headline’s statement inspires me and my colleagues at Ramboll Finland when we seek to find alternative ways to utilize what already exists. The built environment is a bank of building parts that has technically perfectly fine components stocked in it, preserved intact inside buildings. Only processes and systems to utilize them effectively are needed. I sometimes face people itemising reasons and obstacles why reusing building parts is way too difficult. I believe this pessimistic attitude may well up from the insecurity that follows from the building sector changing dramatically. There may also be a disbelief whether the huge leap, which is necessary, can be taken. Some of the items that the sceptics list are well known, some are relevant, and some are just fictional. We need to keep solving them one by one, showcasing with real-life projects that this is possible and acquire more experience to narrow down the gaping hole between the ‘old’ and the ‘new’ way of building.

An important milestone has been reached when the Finnish cluster finished the deconstruction of the pilot building in Tampere this autumn. We succeeded to reclaim several hundred hollow-core slabs, columns and beams intact, ready for use on next building site. It’s been encouraging to gain good test results, both before deconstruction, through a condition investigation, and after deconstruction, as some of the deconstructed elements have been load tested. All has been well from an engineer’s perspective! Now, the reclaimed building parts are being fitted into prospective new building projects. The search for the new building site has not been stalled because of any technical issues but rather by the currently poor market situation.

That final issue to solve – an important one indeed – is the business model that can support reuse. A circular business needs more collaboration among all the players in the field. Technically we are ready to say ‘yes’ to reusing precast concrete elements!

Figure 3. Reclaimed hollow-core slab, deconstructed from the donor building in Tampere.


February 28, 2024
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José Hernández Vargas

Architect and PhD student at KTH Royal Institute of Technology

A precondition for reusing precast elements is a correct understanding of the underlying logic of different building systems and the structural interactions between concrete elements. The analysis of existing precast systems starts with a thorough examination across multiple scales, as building layouts, individual elements and their connections are interdependent.

During ReCreate, several precast concrete systems have been identified and studied. While specific pre-demolition auditing and quality control are critical steps towards reusing concrete elements, this ordering of precast elements operates at an earlier and more abstract level, providing a knowledge base for known precast systems that may apply to multiple instances. This task attempts to provide an overview and develop guidelines for the further classification and digitalisation of precast elements as potential material for reuse. Moreover, the information gathered can serve as methodological guidelines for other systems that may differ from the studied cases but follow the same core principles.

When examining technical drawings from historical precast systems it is important to identify patterns that reveal the systematic ordering of the elements. This initial step involves identifying the underlying measurement system from the axes of the building, from which standard layouts can be inferred in discrete modules. Strict repetition patterns can often be found, especially in residential buildings, where building blocks are constituted by the repetition of a building module defined by a staircase. Similarly, this building module can be divided into residential units corresponding to the individual flats on each floor. Each unit defines in turn a defined arrangement of precast elements that can be precisely estimated for each building.

Thus, architectural and structural knowledge of precast buildings is essential for accurately estimating the building stock and potential for reuse of precast buildings. Given the economies of scale involved in this kind of building, the goal of this step is to build a knowledge base to establish workflows for the ordering and analysis of potential donor buildings for reuse.

Building scale

At the building scale, the analysis centres on the identification and classification of precast structures by structural principles and different building types. Precast buildings can be found in all sorts of applications. Yet, despite the wide range of structural solutions they predominantly follow a limited set of basic structural systems. The most prevalent structural frameworks for precast concrete include the portal-frame, skeletal structures, and wall-frame structures. Structural systems for arranging precast structural systems are closely linked to the building types they serve, responding to the intended program’s requirements. For example, portal-frame structures are most suitable for industrial buildings that require large open spaces. Conversely, for residential buildings wall-frame structures are more often the most cost-effective solution as load-bearing walls also separate living spaces. Beyond buildings completely built out of precast components, specialised subsystems can be found for facades, floors and roofs in combination with other structural systems.

System Skarne 66 (Sweden) and their main structural components form the original technical drawings (left) and as a digital 3D model (right)

Component scale

At the scale of individual precast elements, the foremost classification derives from grouping them by their structural role in the structure, i.e., as walls, columns, slabs, roofs, beams, foundations, and stairs that constitute the structure of the building. These categories are based on the Industry Foundation Classes (IFC) Standard (ISO16739-1), which provides a consistent framework for describing elements within the construction industry. These groups can be understood and modelled as variations of the same parametric object, akin to a family of building components. This process is key for building a comprehensive database of precast elements contained in each building.

To further understand the arrangement of elements that constitute a system, the overall dimensions of each element can be plotted to reveal the dispersion of distinct types within the system. In this example, all the elements are aligned in Cartesian space to define the largest dimension on each axis. This method allows the creation of a ‘fingerprint’ of each building, that shows a concise overview of the dispersion of element types and the individual quantities involved. Alignments resulting from common features such as floor heights and standard modules, can also be observed.

Comparison of the ‘fingerprint’ tool showing the types of elements used in System Skarne 66 (Sweden) and BES (Finland). Dot size indicates the number of elements of each type whereas colour corresponds to the main component categories.

Connector scale

At the connector scale, the different relationships between concrete elements can be related to force transfers and security features to ensure the correct and reliable transmission of forces. Connectors are key to ensuring structural integrity by managing structural loads while accommodating additional stresses and strains that arise from thermal movements, residual loads, seismic loads, and fire exposure, among others. A key aspect for evaluating the connectors is the assessment of the alternatives for disassembly and possibly reusing the connector. Analysing precast buildings at the connector scale allows the identification of the compatibility of precast elements across multiple systems from the analysis and comparison of structural details.

Ordering precast systems across these three scales provides a comprehensive picture of how precast systems are conceived, manufactured, and assembled. This knowledge is instrumental for understanding the possibilities that these elements offer for the next building lifecycle. This ordering will serve as the basis for classifying different precast systems into taxonomies and for the digitalisation of existing precast stocks as material for reuse in future projects.


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.


April 20, 2023
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The success of the ReCreate project would not be possible without the expertise of the people that stand behind it. Our third interviewee is Simon Wijte – Work Package 2 leader and the Dutch country cluster leader. Ivan Fratrić of the Croatia Green Building Council will be conducting the interview. Here is his story:
 
Hello Simon and thank you for doing this interview! Can you introduce yourself and tell us about your background and role in your institution and the project?
 
Of course. I’m a full professor on the chair of sustainment of concrete structures at the Eindhoven University of Technology. My work is split between the University and a consultancy office where I already work for over 30 years. In both positions, my work is tied to concrete structures. I also take part in Eurocode meetings. In my consultancy office, I assess a lot of existing structures and damage to structures from which we can learn a lot. For instance, in 2017. a parking garage which was under construction near the Eindhoven airport partly collapsed and I performed forensic research to determine the cause of that collapse. I’m at the chair of sustainment of concrete structures since 2014. and my approach to this chair is more from a structural engineering than a material point of view, taking into account the application and maintenance of concrete structures in buildings. The material aspect is less relevant compared to a situation when you’re dealing with existing concrete structures in outside environments which are much more aggressive. When it comes to concrete structures, my belief is that concrete structures can be used again and again. The building of our faculty is now over 70 years old. A little over 20 years ago, it was renovated, a new façade, new plans and installations, but the concrete structure was maintained. Now already people are thinking of a new renovation which indeed can be done, but the concrete structures should be maintained again. You can do that over and over and in a way that can be challenging. That’s part of my chair. What you’re facing then is all kinds of problems because, obviously, you have to ensure structural reliability. I don’t know how it’s in Croatia and other countries in the consortium, but in the Netherlands, we’re not careful with the drawings of our existing structures. When you want to reuse an existing concrete structure and you have to assess the structural reliability, you would want to know what kind of rebar is in it, and if you do not know that, you try to investigate in order to find out. Those are the things I’m interested in my research and I receive more and more info about this through my work on the ReCreate project.
 
In your view, what are the professional benefits of working on the ReCreate project?
 
For starters, I have to mention Prof. Rijk Blok who sadly passed away and who got our university involved in the ReCreate project. He was an assistant professor in our unit on the chair of innovative structural design and since the topic of the project is closely tied to my chair, I got involved. Rijk managed the project, go us involved and made it successful, but after his untimely passing, there was a question on how should we continue with the project. At that point, it was already known that Patric Teufel would leave the university so I was basically the only one remaining. I took the task of being the Dutch country cluster leader and the task WP2 leader and it’s definitely a challenge. It fits the topic of my chair quite well, but the circumstances why it happened are very unfortunate.
 
That’s actually what I wanted to ask you because the Dutch country cluster experienced a lot of changes, from Rijk’s unfortunate passing and Patrick’s transfer – how did you manage to handle all of that?
 
There were actually more events than the ones you’ve mentioned that complicated things. When we entered the project, we thought we could have a pilot project of reusing concrete elements on our university’s campus. In the 50’s at the start of the university, there were four larger buildings and a temporary building built in the 50s. Those four buildings got renovated but the temporary building is still there. In that temporary building, there were some precast concrete beams and it was Rijk’s plan to reuse those beams in a fire station that would be constructed on our campus. That plan did not succeed so we had to look for another pilot project. With the help from our partners in IMd, we managed to get in contact with Lagemaat who are performing a challenging and huge pilot project which means that they are already commercially involved in something that is the topic of our project. All in all, personal changes to the project were followed with pilot changes which was challenging at the time.
 
It really mustn’t have been easy, to say the least. Now that you’ve mentioned the pilot, can you give more insight into the building itself and your role within WP2?
 
To be honest, if I had a choice, then work package 2 is something that I would not pick in the first place (laughs). It’s also not so much in my field of expertise, but we’re doing our utmost best for the sake of the project. What we noticed after Rijk passed away is that we’re lacking in staff and in knowledge as well. The Netherlands is not that big and we know each other quite well in the Dutch country cluster, so I looked around and found that a person I know whom was an expert in precast concrete elements, but just as I wanted to contact him, he started working with TNO just weeks ago. They obviously didn’t want to let him go, but since they are a knowledge institute, they were keen to participate in the ReCreate project. I’m of the opinion that adding them was a great move as they have great knowledge in terms of structural reliability, LCA, BIM models, and so on. Their participation in the country cluster opened up the opportunity to use their knowledge. Together, we managed to produce the deliverable for WP2, especially with their knowledge of BIM, which can be very helpful with everything we do in ReCreate. In principle, the basis of the project consists of two things, the first of which is the actual precast concrete element. But, additionally, to that, you want to have a lot of information about that element and those have to be connected to the element and have to remain that way so when that element is stored somewhere on the yard, you have to know all the relevant information about it. That is obviously in the domain of Work Package 3, but in Work package 2, before the deconstruction of the building, you have to know what kind of information is available on that particular element and for that, the BIM models are very useful because you can add a lot of information to those models and the challenging thing is that you can make a 3D model of the building that will undergo deconstruction with all the elements in it and then you can deconstruct it digitally, which means you can take them out and put them out into a database. We have to gain experience in that and connect with people with such knowledge as the BIM model and the database that contains all the BIM models of all the elements will be very important through the complete process. It will be important for both architectural and structural designers, as well as for LCA calculations.
 
That’s actually something that I wanted to ask you as I’ve asked Erik (Stenberg) the same thing. We know what kind of construction the ReCreate project proposes with regards to precast concrete elements and the benefits such as the reduction of carbon emissions and material extraction. That is good all by itself, but I asked Erik whether there are some drawbacks and constraints from an architectural perspective and he said that obviously you can’t do everything with precast concrete elements, so I want to see your perspective as a structural engineer and whether you see any constraints that such construction can have?
 
Let me touch upon the architectural constraints first. Normally, when an architect starts to design a building, he starts from scratch and its up to him whether the floor span will for instance be 7 or 8 meters. He’s free to choose it. It is completely different when you already have a complete structure after the older façade and separation walls have been deconstructed. When you go from an architectural point while having in mind the usage of precast elements, it’s kind of similar but you’re a little bit more flexible. Let’s assume you have a huge database of all kinds of precast elements that are available for reuse in new structures. Then an architect pays you a visit and says ”I want to make a building with, for example, 200 m2 of the ground floor and 200 m2 of the first floor and I want to see how I can create that using available elements”. That’s where the application that we are working on in WP5 is important as it will tell you the availability of elements in the database. In that sense, the architect has a degree of freedom but could be constrained by the availability of certain elements, as well as their location. In that application all kind of aspects can be considered. For instance, carbon reduction by reusing these elements is good, but if an element you need is in Rome and you have to construct a building in Amsterdam, then the reduction of carbon is gone. From an architectural point of view, when you want to reuse a structure in its place, the constraints are the largest. When you want to create a structure using rewon precast elements, you’re more flexible, but obviously, there are limitations, but those limitations can also be in your head.
 
And from a structural point of view?
 
We have to make a distinction between two parts. First on the element level. In the general situation, the elements which are available should be able to withstand the forces that will be applied to them in new structures. So that may not be so challenging until I’m not aware of the reinforcement which is there and I’m not aware of the function of the structure. The second thing is stability – there have to be some shear walls in the structure somewhere to keep it standing up. One of the last challenges is how do we connect the elements. What we see now through the ReCreate project is that disconnecting in majority of the cases is done by sawing structural parts apart and one of my remarks towards that we can do that also in ‘in situ’ structures and not limit ourselves to precast concrete. When demolishing in situ structures, you can also choose to saw off certain elements and try to use them again. ReCreate, as a project, is just the beginning of reuse and is also a small step towards the reuse of steel beams as well…
 
Now that you mention the reuse of steel beams, do you think that should be also focused on eventually? Do they go hand in hand with concrete elements?
 
When making the idea for the project, we limited ourselves purposely to precast concrete because if you expand the scope of research, it only gets bigger and bigger and more complicated and greatly expands in scope. But you’ve identified that correctly as the research can definitely be expanded to other things such as steel structures eventually as well. Research on that part is still ongoing. Research is also being conducted in the Netherlands on the reuse of precast concrete bridge girders.
 
That’s a topic for another project, maybe after ReCreate…
 
What you see is that a lot of things are ongoing and the tasks of structural engineers and architects is changing. I was educated only to design new structures.
 
It’s almost completely new science when it comes to ReCreate.
 
What we now have to do and what we have to educate our students is that in creating new structures, they should also keep in mind that reused elements can again be used or try to design new buildings within older structures.
 
Now that you mention the students…Simon, do you think that the knowledge that comes from the ReCreate project and the whole practice of reusing construction elements will be adopted and implemented into university curriculums?
 
It will and already is. I have some lectures on sustainment of concrete structures which is limited but what you see is that, when you look at master research projects done by students before their graduation, is that they are keen on carbon footprint of concrete structures and how that can be reduced. Because of that, we have a lot of students performing their master research projects within our ReCreate project. There’s one student at TNO looking at structural reliability when using reused elements, we have some students working on diaphragm action between hollow core slabs with particular connections so that they can be reused, and we have student looking after the reliability of non-destructive measurements after the presence of rebar, and lastly we also have a student working on how can we create new connections…
 
So there’s definitely a demand and interest for this topic?
 
Sure, students are very much aware of the problems we are facing with our environment and take this into account when choosing what they will master in.
 
Now that you’ve mentioned this, I’d like to return back to you. You’ve said that the students are highly motivated for topics that pertain to climate mitigation and reducing CO2 emissions. What I want to ask you specifically is whether you are a climate optimist or pessimist in terms of our goals for 2050.?
 
I don’t know whether I’m an optimist or a pessimist. I’m very much aware that things need to change. I try to be mindful of my personal behavior and preferences with regard to my own carbon footprint, but then again I will take a plane when I go for my holidays in the south of Europe. I still drive a car and will strive to buy an electric or a hydrogen one.
 
You’ve mentioned before that the ReCreate project circumstantially ended up in your hands. Now that you’ve spent some time with it, can you tell if you have any internal motivation or drive that underpins your work on the project?
 
Absolutely. The motivation for the reuse of concrete was already there from within my chair. I also must admit that the time I could spend on this topic was limited at the time, but ReCreate enabled me to expand the research. The topic in itself motivates me a lot as we need to work on the carbon footprint of concrete structures. The production of cement is responsible for over 8% of CO2 emissions created by people and that’s quite a lot. On the other hand, when you look at the Pantheon in Rome, the building, with a concrete structure stand there for more than 1900 years. Why do we have to demolish the concrete structures we make after just 50 years and create new concrete? We have to face the challenge that we have to reuse the structures that we already built. Reuse of whole structures is almost ideal, but the second best is definitely to dismantle it into reusable pieces rather than demolish it into coarse aggregate because then you have to use new binder and cement, at the cost of additional carbon emissions.
 
In your view, what is the ultimate goal of the project?
 
If the reuse of concrete elements in new buildings becomes regular within 10 years from now, then we’ve done a good job. We participate in it, produce new knowledge, and try it in pilot projects…if we are able to change the construction industry in this regard – that should be the goal. This goal will not come overnight even if people are initially for it, if we reach that goal, we’ve succeeded.
 
So a wider market uptake and a greater number of experts in these fields would be seen as successes of the project?
 
And also to improve processes for precast structures to make their deconstruction easier. On the other hand, I now have a student looking at a more sustainable design of precast structures of apartment buildings. If you make them easier to disconnect them, it requires less effort for reuse.
 
How do you manage and what are your thoughts on the collaboration within your country cluster and with other organizations in the consortium?
 
The cooperation within the Dutch country cluster is good and is getting better with time. I very much appreciate the collaboration with all the other country clusters because everyone is working from their own area of expertise and together we are able to gain all kinds of knowledge on the matter. It’s not just about structural reliability and structural design. It’s about LCA, material research, the digital design process, and so on. I appreciate very much how Satu (Huuhka) and Soili (Pakarinen) are managing this project.
 
We’re at the end of our interview and I’d like to end it with a personal question. Who is Simon Wijte when he’s not a professor and when he’s not working on the ReCreate project?
 
I like to do a lot of things. I like sports – both watching and performing. Although I’m becoming an old man, I’m 60 (laughs). I used to play field hockey, but my body doesn’t want it anymore. Now I’ve switched to cycling. I like a good dinner, a good glass of wine and being with my family and friends.




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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