Erik Stenberg Archives | Recreate

June 10, 2022
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In the middle of Drottninghög, researchers from KTH are building a pilot building in the form of a pavilion from recycled concrete. The building is part of the H22 City Expo fair, which takes place between 30 May and 3 July.

The building stands on a plot where a preschool previously stood. KTH researchers have been able to use the base plate from the preschool for the building, which is 8×22 meters wide, 4 meters high, and consists of a few hundred tons of concrete. The building consists of 99 percent recycled material.

”The production of new concrete is very resource-intensive and accounts for 3-4 percent of the world’s total carbon dioxide emissions. By using recycled concrete in new buildings, emissions could be radically reduced. Our calculations show that by using recycled concrete in our pilot, we get a reduction of the carbon footprint by 96 percent compared to if we would have used new concrete. So this recycling of concrete points to a way forward.

Today, office properties are demolished from concrete that is perhaps 40 years old to make room for new homes. But that concrete has a much longer technical life than that, 100, 200, maybe up to 300 years as long as it is hot and dry. And if we are to access the carbon dioxide consumption in new buildings, we must have access to these heavy concrete frame elements.” – says Erik Stenberg, professor at the KTH University.

 

EU project on recycling of concrete elements

Professor Stenberg also leads the Swedish part of the EU project ReCreate – Reusing Precast concrete for a Circular Economy – whose purpose is to investigate how to reuse concrete elements in new buildings. The project, which is funded by the EU’s Horizon 2020 program, is led by the University of Tampere and the initiative also includes Eindhoven University of Technology and Brandenburg University of Technology.

Within the framework of the project, all four participating universities will produce two pilots – one digital and one physical. Unlike Tampere, Eindhoven and Brandenburg, KTH started with the physical pilot, the one that is now shown in Helsingborg, and will then make a digital one. The three partner universities’ first digital pilots can be viewed in the form of 3D-printed models of each donor building in KTH’s pavilion pilot.

There will also be descriptions of the various projects. But the exhibition’s focus is on Helsingborg and Drottninghög. Among other things, we present a project on recycling concrete in Drottninghög that some of our students at the School of Architecture worked on last autumn, says Erik Stenberg.

 

Challenge for architects

In addition to his role as leader for the Swedish part, he works with historical analyzes and a mapping of where concrete elements are, when and where they were built, in what form, by whom and for what. Two more KTH researchers are involved in the project – Kjartan Gudmundson from the Department of Sustainable Buildings and Tove Malmqvist from the Department of Sustainability, Evaluation and Governance, SEED.

Kjartan Gudmundson looks at issues such as quality assurance – concrete quality and the presence of hazardous substances – and digitization of historical and new information about concrete elements that can accompany them when they are used again, while Tove Malmqvist works with issues such as life cycle analysis, climate impact, business models, and regulations.


April 29, 2022
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Erik Stenberg, architect and senior lecturer in architecture at KTH – School of Architecture and the Built Environment (ABE) in Stockholm, answered a few questions on why reusing concrete is important in urban development projects.

 

Why is the reuse of concrete important?

– This is where the biggest environmental benefits can be made. If you access the concrete in the structure of houses, you can achieve the largest reduction in carbon dioxide.

 

 Why is it important in urban development projects?

 – It is becoming more and more important to look at the entire life cycle and carbon footprint of the entire urban development and not just individual buildings. We have to look at what was there before and what will come after. We need to make better use of the resources that are already above ground. Also, the historical dimension has nothing to do with carbon dioxide pollution, but with cherishing a legacy, taking advantage of what is good and building on it, and improving what needs to be improved.

 

What are the benefits of using reused concrete?

– This is exactly what we test in ReCreate. The thesis is that the concrete continues to harden during its lifespan and the technical lifetime is much longer than the service life of the buildings. Therefore, reused concrete should be better than new concrete both constructively and environmentally as we do not use and extract resources from the earth’s crust.

 

So concrete is made to last longer than the time we use it today?

 – It lasts much longer. The concrete you usually see is the one that is exposed outwards to the external elements and it is usually hit harder by rain, weather, cold, or salts (depending on where it is) than concrete that has been sitting hot and dry. If the concrete is hot and dry, it lasts forever.

 

What opportunities do you see when it comes to reusing concrete?

 – I look at the material and historical values and that we get a healthier discussion about how urban development should be done, and that we consume fewer resources when we build in the future. This is the biggest change that needs to happen, not just thinking ‘new’ all the time but rather that we take care of what we already have.





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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