Introduction

The construction sector plays a crucial role in the economy of the EU, accounting for 9% of employment with just over 18 million direct jobs [1]. At the same time, the sector is facing several challenges related to the Twin (green and digital) Transition; an ageing workforce and difficulties in recruiting, driving automation and digitalisation [2], and a need to make construction more sustainable and circular [3, 4].

Greening of the construction sector is a paramount concern because this accounts for over 33% of all the waste generated, 40% of all energy consumed, and around 10% of all anthropogenic CO2 emissions [3]. Since the rate of construction is unlikely to be reduced, the mitigation of the environmental impacts of construction must look at alternatives that reduce the environmental impacts associated with construction activities.

Within this context, the Circ-Boost project positions itself to become a focal point and interaction node for different emerging technologies to foster circularity in buildings and the construction sector.

The Circ-Boost project

The Circ-Boost project, whose full title is ‘Boosting the uptake of circular integrated solutions in construction value chains’, began in June 2023 as one of three projects funded under the European Commission’s Horizon Europe HORIZON-CL6-2022-CIRCBIO-02-two-stage call (within Cluster 6: Food, Bioeconomy, Natural Resources, Agriculture and Environment).

The project, coordinated by the Universitat Politècnica de Catalunya (UPC) from Spain, boasts a consortium of 28 partners from 8 countries that will be co-funded by the EU with a grant amount of 7,890,862.50 € over four years.

The overall objective of the Circ-Boost project is to enable and demonstrate an increase in the large-scale uptake of Integrated Circular Solutions (ICS) in European construction value chains. The project's core consists of five pilot projects, deployed in different European regions, highlighting and demonstrating at large-scale ICSs for demolition, construction waste processing, management, and valorisation in new products. Transversal activities of digitalisation will allow collaboration between the pilot projects and more efficient use of digital tools and platforms. Targeted activities are also envisioned for effective exploitation measures, workforce training, leveraging of regional and international networks and communication and dissemination measures and initiatives.

Five pilot projects across Europe

The five pilots of Circ-Boost are in Barcelona (Spain), Paris (France), Belgrade (Serbia), Vesterålen (Norway) and Prague (Czechia), each demonstrating ICSs tailored to each regional environmental, economic, and social conditions.

Pilot 1: Barcelona (Spain)

The old Enmasa/Mercedes-Benz plant in the Bon Pastor district of Barcelona, covering an area of 90.000 m2 is shown in Figure 1. This has been the site of automobile production since the 1950s until it was decommissioned in 2007. Under the new plan of the Municipality of Barcelona, the site is to be transformed into an Industry 4.0 park and residential area, an effort led by the Spanish developer Conren Tramway.

Figure 1. Mercedes-Benz plant in Barcelona (left) and the proposed development (right). 
Copyright: Conren Tramway

The complex-built environment of the site offers a challenge, but also has great potential for the reuse, repurposing, and recycling of the existing structures and their innovative and sustainable use in new projects. The industry that previously existed on the site has caused significant soil contamination that needs to be remediated before the site can be opened for public use, thereby offering potential for the deployment of novel soil remediation techniques.

The activities led by UPC will tackle the demolition stage using BIM-based digital twins for the generation of material and element databanks and stocks for reuse and recycling, as well as phytoremediation and electrokinetic techniques for soil decontamination and reuse. In the design stage, integration of BIM models with LCA and multi-criteria decision-making tools will enable sustainability-based selective deconstruction and demolition and selection of optimal end-use of recovered elements and recycled materials. Finally, in the construction stage, use of low-cost wireless sensors and NFC tags will facilitate recovered element and recycled material traceability.

Pilot 2: Paris (France)

The Greater Paris region is involved in the largest infrastructure project in Europe (Grand Paris Express, a new public transport network consisting of several automatic metro lines around Paris) and its urban landscape is constantly changing in a very dense environment. Additionally, the city is hosting the Olympic and Paralympic Games on its territory in 2024.

To achieve the stated objectives of sustainable development, the entire construction industry must adapt its practices. The construction processes used for new buildings are particularly targeted and the recovery of waste from deconstruction would help reduce the sector's emissions. However, due to a lack of information on the sources, their fragmentation, and a sector that is not yet well structured upstream and downstream, construction waste is not systematically recovered. To meet this challenge, eight French stakeholders, led by Cap Digital, decided to join forces and facilitate the meeting of supply and demand for materials in a circular economy (CE) approach through the development of a digital tool and the creation of a physical platform for matching supply and demand for materials and waste.

Pilot 3: Belgrade (Serbia)

The Balkan region construction industry has been growing over the last decade, but business is being done in a traditional way with insufficient consideration of the environment. A variety of innovative green solutions exist globally, and some of these are being developed in Serbian research institutions. However, the implementation of these solutions is sporadic, mostly due to a lack of practical experience, and comprehensive guidelines and standards. Therefore, a demonstrator house will be constructed within this pilot, using waste and by-product materials with the highest local potential, as shown in Figure 2. Features include using fly ash as a partial replacement of cement (more than 300 million tons of deposited fly ash in Serbia); construction and demolition waste (CDW) with more than 0.5 tons per capita per year of waste is being deposited on illegal CDW dumps in Serbia) reused or recycled as recycled concrete aggregate, reused steel and reused masonry bricks; recycled tyre rubber used for connections of masonry walls (new tyre factories are still opening in Serbia). The efforts are coordinated by the Faculty of Civil Engineering, University of Belgrade (FCE).

Figure 2 Demonstrator house to be built within pilot 3 in Belgrade. Copyright: FCE

Pilot 4: Vesterålen (Norway)

The city of Vesterålen, located well within the Arctic circle, is constructing the GaiaVesterålen museum as an international showcase that will present how joint action across industries and sectors for ambitious climate and environmental goals can work in the region. The museum building will be a state-of-the-art high-tech exhibition with a model that integrates a combination of projection mapping, AR, VR and digital gaming. The pilot, led by Museum Nord, will focus on the entire construction value chain, from the demolition of two local buildings to innovative green design approaches to the construction of the museum building using cutting edge solutions for the reuse and recycling of materials from previously demolished buildings.

Within the demolition stage detailed mapping of the concrete part of structures prior to demolition will be performed (using innovative methods to precisely evaluate and minimise the quantity of concrete labelled as contaminated), employing selective demolition and sorting of recyclable and contaminated concrete. Within the production stage, modern machinery and modern crushing and sorting techniques, certification and properties evaluation will be performed to produce high-quality recycled aggregate concrete (RAC). Finally, within the construction stage, logistics connected to RCA transportation and adjustment of the concrete mix during production will be optimised.

Pilot 5: Prague (Czechia)

The pilot to be developed within the Circ-Boost project in Prague is a residential project to be built in a brownfield area at the site of a previous sugar factory in Modřany. This project consists of several residential buildings as well as infrastructure, services, green zones, and a small square. The developer is Skanska Reality member of Skanska global group. The goal for this project is to use RAC as much as possible for structural elements and demonstrate that this is a sustainable and circular solution for the industry, in particular, relying on Rebetong (Skanska’s registered trademark for concrete made of up to 100% of recycled aggregate) as a replacement for natural aggregate. The pilot project shall serve for industrial upscale of Rebetong for: (i) base concrete slabs and (ii) reinforced concrete walls. As well as for new applications: (i) façade panels; (ii) wall tiles with exposed surface; (iii) urban furniture.

Figure 3 Circ-Boost pilot 3 in Prague. Copyright: Skanska

3D circular economy web map

To aid with the upscaling of the ICSs, a 3D web map will also be developed within the project as shown in Figure 4. The main objective of this solution is to collect, process, create, and display data which will facilitate better recovery (especially reuse and high-quality recycling) of building materials during renovation and demolition and better use of recovered materials. This dataset is aimed at becoming a special CE feature dataset for the buildings’ digital logbooks initiative that supports the EU’s transition to a more circular construction industry. More specific objectives are to create a digital solution, i.e., circular building ecosystem at the municipal level that will integrate the spatial data and building information modelling (BIM) models of existing buildings. This will enable a generation of BIM-based CE passports with all relevant CDW and CE indicators.

Figure 4 Circ-Boost 3D web map. Copyright: FCE

Circ-Boost contribution towards a zero-emission EU building stock

Although the focus of the Circ-Boost project is on integrated solutions for boosting circularity, many of these solutions also reduce emissions and help bring to reality a zero-emission EU building stock.

Firstly, reusing materials in new construction or building with recycled materials reduces emissions associated with new construction as all the emissions associated with the used material up until the point of ‘end-of-waste’ are allocated to the previous building being demolished.

Secondly, several of the Circ-Boost pilots (e.g., Pilot 1), consist of new construction on the same site of an old structure and therefore has zero transport-associated emissions (recycling and soil decontamination is done on-site). This is a considerable benefit and emissions reduction, because even when recycling is done, this tends to be off-site.

Finally, tools such as the 3D CE web map can, besides providing a material databank, be used as a tool for estimating energy efficiency of the existing building stock, thereby facilitating renovation scenarios that lead to a reduction of operation-associated emissions.

Conclusions

By implementing targeted pilots in Barcelona, Paris, Belgrade, Vesterålen, and Prague, the Circ-Boost project showcases practical ICSs contextualised to different European regions. These pilots serve as demonstrations of the feasibility and effectiveness of circularity in construction, emphasising the tangible impact on sustainability and resource efficient use.

The project includes the development of a CE platform to facilitate collaboration, data-driven decision-making, and efficient construction material recovery and management.

With engagement from a consortium of 28 partners across eight European countries, the project aims at boosting more sustainable and circular practices and approaches into the construction section. Through pragmatic solutions and innovative pilots, the Circ-Boost project is set to emphasise the practicality and scalability of circular approaches.

References

[1] EUROSTAT, Enterprise statistics by size class and NACE Rev.2 activity (from 2021 onwards) [SBS_SC_OVW__custom_4672113]
[2] Duchêne, V., et al., Identifying current and future application areas, existing industrial value chains and missing competences in the EU, in the area of additive manufacturing I. European Commission DG Internal Market, Entrepreneurship and SMEs. 2016
[3] COM/2020/98 final (2020). A new circular economy Action Plan for a cleaner and more competitive Europe. European Commission
[4] COM/2019/640final (2019). The European Green Deal. European Commission