Sustainability
Industry trends

Recycling in the Circular Construction — Rational Use of Raw Materials

14 June 2022

There are a lot of talks these days about the transition to a circular construction, but what does it really mean? In essence, circularity is about eliminating the creation of waste, for example, in the construction industry.

ROCKWOOL Group recycled roughly 163,000 tonnes of stone wool waste in 2020

ROCKWOOL Group recycled roughly 163,000 tonnes of stone wool waste in 2020.

Utilising existing materials and products efficiently by recycling and reusing — keeping the value of products, materials, and resources for as long as possible — is part of the circular construction. This transition is undoubtedly an essential contribution to the construction industry's efforts to develop a sustainable, low carbon, resource-efficient, and competitive economy. 

Raw materials are essential for the production of a broad range of goods and applications used in everyday life. They are present in all industries across every stage of the entire supply chain. Therefore, they are also crucial for the strong European construction industry and are seen as an essential building block of the EU’s growth and competitiveness.  

In the Construction and Demolition Waste: challenges and opportunities in a circular economy, [1] ‘raw materials are not taken out of their cycles but remain in the economy as long as possible through their efficient and intelligent use.’ [1] End-of-life products must be considered as resources for another cycle, while losses and stocks of unused materials must be minimised all along the value chain — creating a closing material loop. 

Europe’s Construction and Demolition Waste Problem in Numbers 

Buildings and construction elements are designed to be easily adaptable or demountable with almost no demolition. Yet, we know that the construction and demolition phases in the building sector can be a significant source of CO2 emissions and waste production. In fact, about 374 million tonnes of construction and demolition waste (C&DW) were generated in 2016 [2] making it is the largest waste stream in the EU by weight.  

The waste framework directive 2008/98 / EC had the objective of recycling 70% of construction and demolition waste by 2020. However, even though the raw material recovery rate is high — with an average of 88% in 2018[3], only around 50% of C&DW is currently recycled — despite the efforts of some countries — and often downcycled.[4] 

The circular construction aims to foster an economy that retains as much of the value of materials as possible, for as long as possible. This means that the quantity of recycling or reuse is no longer the only objective: the type of recycling and the avoidance of downcycling is crucial. To transit to a circular construction, action that goes beyond waste management and improved recycling is necessary, as all products’ lifecycle stages need to be involved.  

‘Circular economy inspired action made in the initial stages of a building’s lifecycle may affect the management of the building’s waste in a profound way.’ [1] 

Construction Industry Accounts for 38% Of CO2 Emissions 

The management of materials is responsible for two-thirds of the world's greenhouse gas emissions, the OECD said in Global Material Resources Outlook to 2060 report.[6] And, by 2060, the use of raw materials will double, with obvious consequences in terms of CO2 emissions.[6] 

As reported by EASAC (European Academies Science Advisory Council) in Decarbonisation of buildings: for climate, health and jobs, the construction and maintenance of buildings use up almost half of all the materials that enter the global economy — generating about 25% of all greenhouse gas emissions.[7]  

Worldwide, cementitious materials make up more than half of all the materials we use. According to the data of the International Energy Agency [5], a staggering 2.2 billion tonnes of CO2 — which is about 7% of the worlds CO2 discharges — are caused due to cement production. To make cement, fossil fuels or waste are burned to superheat lime in a kiln and produce calcium oxide — a chemical process that results in further CO2 emissions. 

What does the recovery rate mean?

Eurostat defines the recovery rate as the amount of C&DW that is prepared for reuse, recycled or subject to material recovery, including backfilling, divided by the C&DW treated.

Bar chart - Steel and cement demand

Furthermore, by 2050, the materials used for construction will result in emissions of 250 million tons of CO2 [1]. This will be the case if the current procedures of a linear economy — use of resources, the transformation of the latter, consumption of manufactured goods, waste — continue to be followed.  

And it is the raw materials and how we decide to use them that makes the difference.  

Why Are Recycling Raw Materials Crucial for the Economy and the Environment?  

Extracting and processing new materials requires a lot of energy and uses chemicals that can leak into the ecosystem, causing serious harm to the local environment. Recycling, on the other hand, reduces the need for mining and saves energy, so it is both a cheaper and more environmentally friendly choice. In other words, using secondary materials instead of virgin materials requires less energy.

Bar Chart - Comparison of the circular material use rate 2011 and 2020

For example, although steel makes up only 2% of the total weight of materials used in buildings, due to the emissions associated with its extraction and final manufacturing, it accounts for 25% of their carbon footprint. [8] Reusing or recycling steel instead of extracting the ore can significantly reduce greenhouse gas emissions. The scientists proved that using one ton of recycled stainless-steel scrap saves 4.3 tonnes of CO2 in stainless steel production. With carbon steel, the average saving of using one tonne of steel scrap is 1.67 tonnes of CO2.

This means that if you use a ton of carbon steel scrap as raw material input instead of using ores, an amount of CO2 equivalent to the emissions of an average car with a petrol engine in Germany driven over a distance of around 9,000 kilometres is saved. The research team calculated that the scrapping bonus is between 79 and 213 Euros per ton of carbon steel scrap and even between 158 and 502 Euros per ton of stainless-steel scrap used in the production of steel. [9] 

In the graph below, a circular economy scenario is shown whereby CO2 emissions from building materials could be reduced by 53% in millions of tonnes of CO2 by 2050. 

CO2 emissions from building materials - bar chart

Recycling, Upcycling, and Downcycling  

As it accounts for around 36% of all waste generated in the EU [10], construction and demolition waste are identified as a priority area in which recycling is a crucial issue. The construction and demolition sectors are also challenged to improve the quality of their products. 

However, we normally use the term "recycling" very broadly; we use the term to indicate any activity that involves the recovery and reuse of raw materials that would otherwise be sent to landfill. Such simplification should be avoided: recycling can actually be an extraordinarily complex process. 

The construction industry is notoriously fragmented. Additionally, due to poor design and lack of information about a building’s material composition, opportunities to facilitate material reuse and recycling are missed. If each component had a digital “passport” that clearly defined its material composition alongside possible reuse options, materials would be far less likely to be wasted. In Amsterdam, improving the reuse of materials in the construction of 70,000 new apartments before 2040 could reduce waste by half a million tonnes. [11] 

Reuse keeps the materials at their highest possible value, considering invested time, money, energy, and creativity. However, reuse is not possible for all materials, making recycling infrastructure crucial. Moreover, using recycled instead of virgin materials reduces CO2 emissions by 40–70% [8].

In order to develop the market for secondary materials, buildings need to be designed with recyclable, recycled, and reused raw materials. Furthermore, in order to enable these activities, recycling and reusing infrastructure must be developed, as well as the quality of secondary materials.  

Turn Waste into High-Quality Secondary Materials 

In a circular construction system, waste that can be recycled or reused is returned to the economy. Secondary materials, which are recycled, can be exchanged, and shipped just like primary raw materials. However, due to waste regulation and transportation over borders, they only stand for just a small fraction of the materials used in the EU.  

It is vitally important to increase the use of secondary raw materials in the construction industry and enable more efficient waste management with easier options for recycling and reuse towards a real adoption of circular practices in the construction industry. 

At Rockfon, we use stone wool as our primary material. It is a fully closed-loop product and can be recycled repeatedly without any degradation in quality. ROCKWOOL factories recycle wool waste to create briquettes that we use in our manufacturing process. This reduces the amount of virgin stone needed. We also upcycle secondary materials from other industries. By that, new high-quality stone wool products are produced, with a high percentage of recycled content. 

In fact, ROCKWOOL Group recycled roughly 163,000 tonnes of stone wool waste in 2020. And from 29% to 64% of our product composition is from recycled materials, depending on the product choice. We offer the possibility to our customers in many European markets to recycle old stone wool ceiling tiles or cut-offs from installation. We have established partnerships in many of the countries we operate, and we can support you with your request for recycling

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Sources: 

  1. “Construction and Demolition Waste: Challenges and Opportunities in a Circular Economy.” 2020. n.d. Eionet Portal. 2020. https://www.eionet.europa.eu/etcs/etc-wmge/products/etc-reports/construction-and-demolition-waste-challenges-and-opportunities-in-a-circular-economy. 
  2. “Construction and Demolition Waste: Challenges and Opportunities in a Circular Economy — European Environment Agency.” 2020. n.d. European Environment Agency. 2020. https://www.eea.europa.eu/publications/construction-and-demolition-waste-challenges. 
  3. “EUR-Lex - 32008L0098 - EN - EUR-Lex.” 2018. Europa.eu. 2018. https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=celex%3A32008L0098. 
  4. “Recovery rate of construction and demolition waste” 2022. Europa.eu. 2022. https://ec.europa.eu/eurostat/databrowser/view/cei_wm040/default/table?lang=en. 
  5. Bumanis, Girts, Aleksandrs Korjakins, and Diana Bajare. 2022. “Environmental Benefit of Alternative Binders in Construction Industry: Life Cycle Assessment.” Environments 9 (1): 6. https://doi.org/10.3390/environments9010006. 
  6. “Global Material Resources Outlook to 2060: Economic Drivers and Environmental Consequences | READ Online.” n.d. Oecd-Ilibrary.org. Accessed January 29, 2022. https://read.oecd-ilibrary.org/environment/global-material-resources-outlook-to-2060_9789264307452-en#page17. 
  7. “Decarbonisation of buildings: for climate, health and jobs.” n.d. The European Academies' Science Advisory Council. 2021. https://easac.eu/fileadmin/PDF_s/reports_statements/Decarb_of_Buildings/EASAC_Decarbonisation_of_Buildings_Web_publication030621.pdf. 
  8. “Building a World Free from Waste and Pollution.” n.d. Ellen MacArthur Foundation. https://ellenmacarthurfoundation.org/articles/building-a-world-free-from-waste-and-pollution.  
  9. Brunn, Michael. 2020. “Use of Steel Scrap Saves Billions in Climate and Environmental Costs.” RECYCLING Magazine. March 25, 2020. https://www.recycling-magazine.com/2020/03/25/use-of-steel-scrap-saves-billions-in-climate-and-environmental-costs/
  10. “Recycling of Secondary Raw Materials for a Sustainable Optimization of Construction Processes in Civil Engineering.” n.d. Ec.europa.eu. Accessed January 29, 2022. https://ec.europa.eu/growth/sectors/raw-materials/eip/raw-materials-commitment/recycling-secondary-raw-materials-sustainable-optimization-construction-processes-civil-engineering_en. 
  11. “Review of Completing the Picture: How the Circular Economy Tackles Climate Change.” 2019. Ellen MacArthur Foundation. https://circulareconomy.europa.eu/platform/sites/default/files/emf_completing_the_picture.pdf.