Circular economy

A circular economy can be described as ‘one where materials are retained in use at their highest value for as long as possible and are then reused or recycled, with little or ideally no residual waste.’ (Ref: London Plan Guidance - Circular Economy Statements).

A major driver for the advancement of a more circular economy is the decarbonisation of a new development, with reuse of existing materials often leading to significant upfront embodied carbon savings. 

Strategies for embedding practice that support a more circular economy continue to evolve, with actions often grouped under key priorities to Reduce, Reuse and Recycle to avoid, wherever possible, resultant waste.  

The role of a  wider ‘technological eco-system’ or ‘ industrial symbiosis’ is essential for circular economy thinking. For example where the by-product or ‘waste’ from one manufacturing or industrial process is useful resource for another. It is not essential to assume that the best action to support a more circular economy is for materials to be recycled into themselves. The issues are complex and need to be considered holistically.   

Similarly, design for efficient use of resource manufacture, construction and use and beyond are all important, including waste reduction at each life cycle stage, design for a long service life and facilitating future reuse. 

Different parts of a building require different approaches to reuse or recycling in response to their differing potential life cycles. The concrete structure of a building can last for 100 years or more whilst services or internal fixtures may be replaced many times over the life of a building.  This concept of building in layers is a recognised circular economy approach for new construction. 

UK Concrete Circular Economy Framework

For well over a decade the UK Concrete industry has been collecting data, reporting against targets for improvement on a range of sustainability performance indicators, as part of the UK Concrete Sustainable Construction Strategy. These include the use of recycled content, resource efficiency and reducing waste- to- landfill.  The ready-mixed, precast and masonry sectors have also developed and acted upon Resource Efficiency Action Plans (REAP).   

The approaches, priorities and solutions for achieving more circularity within the built environment have matured since this original strategy was developed and circular economy is now one of the four areas of focus of the refreshed UK Concrete Industry Sustainable Construction Strategy Framework published in 2024. The focus for UK Concrete is to continually develop these priorities for the concrete sector and its associated supply chain, as well as collaborating with stakeholders to evolve the understanding of concrete’s role in supporting a circular economy across its whole life cycle. Read more.  

Design strategies for the use of concrete to support a more circular economy

Considerations for designers and engineers for new developments include: 

• Reuse existing concrete resources on site. Concrete typically has a long service life and requires little maintenance. There are plenty of examples of existing concrete frames and sub structure that have been retained for reuse, and the methodology for assessing their suitability is well established for structural engineers. More information on reuse of concrete can be found here. 

• Deconstruct and reuse existing concrete elements where possible. This could be onsite, or for reuse elsewhere. The durability and long service life of concrete offers benefits here, and plenty of small- scale concrete products can be reused elsewhere, such as fencing and paving. Opportunities may be limited by how the elements have been assembled. While not yet current practice, opportunities for reuse of cast in-situ concrete structural components are being investigated and examples of repurposed structural precast are emerging.  

• Deconstruct to optimise the recycling potential of the crushed concrete. The recycling and use of recycled concrete for use in construction is a well-established practice in the UK. New opportunities are arising for the use of the resultant crushed concrete, which can be facilitated by the method of demolition and processing. More information on recycling concrete can be found here. 

• Specify and design using secondary materials. All the typical materials used to make concrete include, or can include, recycled or by-product materials from other industries. These include  steel reinforcement, secondary cementitious materials and aggregates. Portland cement is also manufactured using recycled and secondary materials. More guidance is available here. 

• Improve material efficiency through structural design. Significant improvements in the material efficiency of a concrete  frame can be achieved through reducing design loads, reducing spans and selecting the most efficient structural system for the design criteria. Further guidance and resources are available here and at Concrete Compass: Material Efficiency.

• Use the concrete to avoid or reduce the use of other materials. Concrete often does not need any coatings or paint to protect it against deterioration or to meet fire performance and acoustic requirements.  Over the life of the building, exposing the surface of structural concrete reduces the resource use and waste associated with ceiling and linings at installation and over the life of buildings.   

• Design for long life and to facilitate future reuse. Concrete is highly durable, with internal concrete frames able to achieve a 100 year design life with no additional cover or concrete mix requirements when compared to a typical 50 year design life. Spatial decisions at early design stage can embed flexibility and adaptability in the design to optimise this long service life. 

• Consider design for disassembly. For some structures this might be an appropriate solution, particularly shorter lived uses such as car parks. Since the concrete structure is usually the element that is retained for longest, design should facilitate the disassembly of shorter-lived construction elements, such as partitions, ceilings and finishes. 

More resources and guidance on Circular Economy is available via the Concrete Compass on Circular Economy.