deconstruction - Recreate

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

March 15, 2024

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.

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.

by ReCreate project

June 19, 2023

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As part of the activities under Work Package 2 of the ReCreate project, our project partners developed a BIM-based pre-deconstruction audit. We sat down with Marcel Vullings from TNO to gain more insight into the audit and to get more details. Here’s our full interview with him:

I: What is the main focus of the pre-deconstruction audit in the ReCreate project?

M: The main focus of the pre-deconstruction audit in the ReCreate project is to gather and validate the information that is crucial for the deconstruction process. This involves putting significant effort into tasks such as inspecting archives, conducting inspections and testing, and ensuring the traceability of information. The goal is to establish a comprehensive understanding of the structure and elements involved, making connections between the gathered information and the actual components. By undertaking these steps, the pre-deconstruction audit aims to provide a solid foundation for the subsequent deconstruction activities.

I: What type of data is gathered during the survey of the existing building in ReCreate?

M: The pre-deconstruction audit process begins with gathering information from the archives to prepare for the building inspection. Once the necessary preparations are made, the next step is to inspect the building itself. Before conducting the inspection, it is important to strip the building of loose items such as carpets and wallpaper to ensure clear visibility of the structural elements. This provides an opportunity to thoroughly examine the structure.

During the inspection, several factors are considered. The overall state of the structure and its elements is assessed, looking for any signs of damage, cracking, or corrosion. Deviations from the norm are noted, such as brown spots that may indicate possible corrosion. Detailed documentation is crucial, including taking pictures and measurements of cracks and other issues. Videos are recorded to allow for a review of the inspection back at the office. Both overall views and close-ups of specific details are captured.

To ensure accurate understanding, it is important to make sense of the gathered information and create a cohesive narrative. Measurements of various dimensions are taken, and a comparison is made between the building’s drawings and its actual construction. Changes may have been made over time or during the building process. Digitalizing the building, its structure, and its elements is also part of the process, utilizing different types of measuring devices.

Finally, both the interior and exterior of the building are inspected to ensure a comprehensive assessment.

I: How is the identification system in ReCreate utilized to trace and couple physical elements with data?

M: Tracking and tracing each separate element is of utmost importance throughout the entire process. This is essential because when designing a new structure, structural engineers need to provide calculations, reports, and drawings to demonstrate that the structure is safe and compliant with regulations. Various checks, including those by municipalities, are conducted to ensure that each part of the structure performs as specified in the documentation.

For reused elements, the information associated with each element is crucial. Any mix-up or uncertainty regarding the information of a particular element can have severe consequences. Therefore, if there is any doubt about the information of an element at any point in the process, it cannot be reused and becomes useless. The objective, however, is to reuse elements whenever possible.

To achieve effective tracking and tracing, it is essential to connect the information to the corresponding elements such as columns, beams, walls, slabs, etc. This can be accomplished by attaching tags to the elements during the initial phases of deconstruction or up until the moment an element is deconstructed. It is crucial not to delay this process. The location of an element in the old structure serves as the only clue to establish the connection between the physical element and the associated information.

Tags can take the form of marks, such as barcodes, QR codes, or plastic tags placed on the elements. Alternatively, electronic tags can be used. These marks and tags need to be secure and durable enough to withstand deconstruction, transportation, storage, handling, reconstruction, as well as exposure to various weather conditions, heat, and sunlight. They must be foolproof.

In addition to secure marking, establishing and maintaining a robust connection with a database or information system is essential. Building Information Modeling (BIM) models of the elements can also be utilized to ensure a continuous and reliable link between the physical elements and their corresponding information.

I: Why is it important to identify hazardous and/or toxic materials before dismantling a building in the ReCreate project?

M: Strict regulations are in place to address hazardous and toxic materials, aiming to establish and uphold a healthy work environment for workers, ensure the well-being of the surrounding area, and contribute to a healthy overall environment. It is crucial to adhere to these regulations to create a safe and sustainable space. Materials falling under this category cannot be reused and must be handled separately and disposed of in a safe and environmentally friendly manner.

To effectively manage these materials, it is essential to determine their presence within the building. For instance, in the case of asbestos, special suits are required for safe removal. The process of identifying and dealing with hazardous materials is subject to scrutiny by the department of health. Mistakes in handling these materials can have severe consequences, including loss of life or significant fines.

Compliance with the regulations ensures the protection of both workers and the environment, emphasizing the importance of following proper protocols for the safe removal and disposal of hazardous and toxic materials.

I: What methods are used to record visual or detectable damage to elements in the pre-deconstruction audit?

M: At various stages throughout the process, the structure and elements undergo inspections to assess any damages, degradation, or cracking. These inspections occur from the initial assessment until the element is reassembled in a new building. The goal is to determine whether an element can be reused and ensure its proper performance throughout its new lifespan, which could extend for several decades or even longer.

Inspections rely on a combination of visual examination by experts, along with the use of pictures, videos, and electronic measuring devices such as point cloud measurements. Additionally, simple tapping on the surface of the concrete can provide valuable information. Specialized equipment like the Schmidt hammer and ferro scanners may also be employed for more detailed analysis.

However, it is crucial that these inspections are carried out by specialists, as not every crack or damage is necessarily catastrophic. Concrete structures commonly exhibit cracks, which are even accounted for and described in the Eurocodes—design standards for concrete structures. The size and location of cracks play a significant role in assessing their impact and determining whether they conform to acceptable limits. Therefore, the expertise of specialists is vital in accurately interpreting the findings of these inspections.

I: How does the surveying process in ReCreate address stability issues during deconstruction?

M: Before carrying out the deconstruction itself, a structural engineer investigates the precast concrete structure to determine the optimal approach for dismantling the building, including the sequence of removing each element. This process must prioritize safety and ensure the stability of the remaining structure throughout the deconstruction process. To achieve this, a comprehensive deconstruction plan is created, which may involve implementing measures such as temporary scaffolding to stabilize the structure during the deconstruction phase.

I: What information does the survey aim to gather regarding the construction methods and structural systems of load-bearing elements?

M: This process can involve a considerable amount of technicality, but it can also be straightforward. Take, for instance, the location of a building, which provides valuable insights into its wind loading. Various factors differentiate a building situated at sea, inland, on an open plain, or within a city. Additionally, the dimensions of the building are crucial. Larger buildings must withstand greater and higher wind loads compared to smaller ones. However, for a structural engineer to accurately assess the load-bearing capacity of each precast concrete element, precise knowledge of the element’s location, layout, and dimensions is required. It is also essential to have information about the material properties of the steel and concrete, as well as how they are interconnected within the structure.

Furthermore, even the positioning of an element within the building, such as a column, provides relevant information. A ground-floor column typically exhibits greater load-bearing capacity than a column located at the top of a building. All of this information serves as valuable clues to determine the load-bearing capacity of each precast concrete element. The more comprehensive the available information, the more accurate the assessment becomes. In essence, if the dimensions of an element, a detailed description of the reinforcement, and the correct material properties are known, a structural engineer can reverse engineer the load-bearing capacity of that element. This process can be complex, but having additional information significantly simplifies it.

I: How does the acquired knowledge during the survey stage contribute to deconstruction planning in ReCreate?

M: Yes, this information is crucial for creating a deconstruction plan and ensuring the feasibility of the deconstruction process. Without it, the undertaking becomes unsafe and hazardous. A comprehensive deconstruction plan is essential, requiring detailed information about the building, structure, materials, connections, and the shape of the elements, among other factors. For instance, if the method of connection between elements is unknown, it becomes challenging to determine the appropriate cutting approach to separate the elements from the structure effectively. Consequently, incorrect cutting can lead to damage and render the elements unusable.

I: How does the pre-deconstruction audit combine modern survey technologies with traditional building surveying techniques?

M: During the audit, a wide range of methods are employed, with each task requiring its own specific technique. Various techniques and tools are utilized to simplify the process and gather accurate information quickly and reliably. These techniques and tools can be quite straightforward, such as visual observation, using a simple ruler for measurements, or employing a laser scanner to measure distances. Drones may also be employed to access challenging locations, such as high facades of buildings. Ferro scanners play a crucial role in detecting reinforcement within the concrete elements, while even a loupe can be utilized to measure the width of cracks in concrete. Additionally, pictures and videos are used to digitally measure elements. The available range of techniques and tools is extensive, offering a diverse array of options for conducting the audit.

I: What role does non-destructive electromagnetic and radar identification play in the ReCreate project, specifically during the survey of the donor building?

M: The non-destructive nature of obtaining information from precast concrete elements is evident, as the goal is to avoid damaging or destroying the elements in the process. Therefore, techniques employed to gather information must be non-destructive. In concrete, one critical aspect of obtaining information pertains to the location and dimensions of the reinforcement within the precast concrete element. These factors determine the element’s load-bearing capacity. Concrete elements require steel reinforcement, with concrete handling compression and steel managing tension—an ideal combination.

Steel can be detected using magnets, whether traditional or electronic magnets utilizing electromagnetics. A scanner is used to glide over the surface of the concrete, while the magnets detect variations and discrepancies. The scanner’s software interprets this information, providing readable details about the reinforcement within the concrete element. However, it is important to acknowledge the limitations of this technique. In certain situations, these methods may not be entirely reliable. To ensure accurate findings, it is essential to gather collaborating information from various sources, such as drawings, old calculations, and even resorting to destructive testing if necessary. Destructive testing involves breaking a portion of the element to visually examine it. Although this may result in sacrificing some elements, it becomes a last resort when other methods fail to provide satisfactory information.

I: How does ReCreate plan to bridge the gap from deconstruction to controlled disassembly for future buildings?

M: ReCreate plans to bridge the gap from deconstruction to controlled disassembly for future buildings through extensive data gathering and knowledge sharing. The project aims to learn from real-life pilot projects, examining what works, what doesn’t, and identifying areas for improvement. One important observation made during these pilots is that plastic tags are not suitable due to the fading of text under sunlight, rendering them unreadable. This highlights the need to explore alternative tagging methods.

Various methods of cutting through elements were explored, including sawing (using blades and cables), drilling, and high-pressure water jets. Each method has its pros and cons, and it is essential to understand and utilize them appropriately. There is no one-size-fits-all approach or tool for deconstruction. Efficiency and safety must be combined, taking into account the specific requirements of each project.

The ReCreate project, with its pilot projects conducted in different countries, aims to collect valuable data, information, and experiences. This wealth of knowledge is expected to have a significant impact, benefiting numerous projects in the future. TNO, as part of the project, plans to apply this new knowledge to other projects, including different types of deconstruction projects such as infrastructure, as well as exploring other materials like steel and wood structures. The research conducted within ReCreate has the potential for widespread application across various domains.

I: What role does cost-efficiency play in the development of the pre-deconstruction audit process in ReCreate?

M: Cost-efficiency plays a significant role in the development of the pre-deconstruction audit process in ReCreate. Currently, cost remains the primary factor driving the choice of methods for recycling concrete structures. Traditional demolition is often perceived as the cheapest option and, consequently, the most widely employed approach, despite its limited environmental friendliness. However, there is a need for a shift in societal mindset towards normalizing the reuse of materials and products as the first and natural step, rather than defaulting to purchasing new ones.

Lowering the costs associated with deconstruction and the reuse of precast concrete elements is a crucial objective. In this regard, ReCreate’s efforts are commendable, as the project strives to provide valuable services in enhancing efficiency within the field. Furthermore, implementing regulations and other measures can contribute to achieving cost efficiency and promoting sustainable practices in the industry. By addressing cost barriers and highlighting the economic benefits of deconstruction and material reuse, ReCreate aims to drive the adoption of more environmentally friendly practices in the construction sector.

I: How does ReCreate aim to optimize the detection methods in relation to the prefab systems and decoupling methods?

M: ReCreate aims to optimize the detection methods in relation to prefab systems and decoupling methods by considering them as additional tools rather than the sole approach. While detection plays a role, it is not the sole method employed. The study of original design drawings and calculations serves as the primary source of information for decoupling. Additionally, inspections and a comprehensive understanding of precast concrete structures provide a complete picture of the building. Detection techniques can be utilized to identify reinforcement in connections and other anchor systems where applicable. By integrating various approaches, ReCreate seeks to enhance the overall effectiveness of detection methods in relation to prefab systems and decoupling processes.

I: What is the significance of testing and validating the generic approach developed in ReCreate’s real-life pilot projects?

M: Testing and validating the generic approach developed in ReCreate’s real-life pilot projects holds great significance. It offers a comprehensive understanding of the entire deconstruction and reassembly process involving reused precast concrete elements. This includes all the associated aspects such as life cycle assessment (LCA), life cycle costing (LCC), compliance with regulations, development of business models, effective planning, information management, data gathering, innovative design approaches for structures using reused elements, creation of new connections, and the integration of old and new components through demountable connections.

The ability to observe these processes in real-life scenarios through four distinct pilot projects in different countries, involving diverse organizations and companies, provides invaluable insights. It allows for a thorough examination of the practical implementation of the generic approach, assessing its feasibility, effectiveness, and potential for scalability. These pilot projects serve as a robust testing ground, offering the opportunity to refine and validate the developed approach based on real-world challenges and outcomes. Ultimately, the knowledge gained from these pilot projects will contribute to advancing sustainable practices in the construction industry and facilitating the widespread adoption of the ReCreate project’s principles and methodologies.

by ReCreate project

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.

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