2020 marked a major milestone in driving forward the circular economy approach for sustainable growth and development when the potential for construction and demolition waste (CDW) was showcased through the construction of prefabricated and energy-efficient building concepts – all derived from our most abundant waste stream.
It has been said before that sand and stone resources recovered from CDW are suitable for high-value construction and infrastructure projects when supported with the appropriate processing practices and technology, but that a behavioural shift is also required to tackle reluctance within the construction industry towards the adoption of recycled sand and aggregate.
Now, with the support of our industry-leading wet processing technology, a team of researchers have demonstrated how CDW can be utilised for the construction of residential and non-residential buildings rather than being destined for landfill or low-value applications, such as backfill.
RE4, the EU-funded initiative behind the project, first launched in 2016 with the aim to champion the potential of CDW in support of the EU’s ambitious targets to reuse, recycle and recover a minimum of 70% (by weight) of non-hazardous CDW by 2020.
Its purpose was to design and develop a prefabricated energy-efficient building concept that could be easily assembled and disassembled for future reuse.
CDE was one of 13 partner institutions from eight different countries involved in the project, which spanned three and a half years from September 2016 to February 2020.
Our solution significantly improved the quality of sand recovered from CDW compared to typical recycling plants commissioned at the time. Its solution would underpin the future success of the project and its aims to minimise the environmental impacts of the construction industry through the reuse and recycling of CDW.
Prior to material being processed through the CDE solution it was passed through a robotic sorting system, designed by RE4 project partner STAM, to remove contaminants. After intensive testing in the SIIT (Sistemi Intelligenti Integrati Tecnologie) laboratories in Genoa, Italy, the robotic sorting system was deployed at the site of one of CDE’s long-term customers, Sheehan Group, in Oxford, where it was assembled and tested in a real-world setting to process incoming CDW material typical of most active CDW processing sites.
With a proven solution now developed and contaminants effectively removed, CDE supplied the recovered CDW material from another of its customer sites, Brewster Bros. in Scotland. Over 200 tonnes of recovered CDW would be shipped to Creagh in Northern Ireland to produce the innovative concrete building solutions used in the development of the RE4 project’s ground-breaking prefabricated and energy-efficient building materials and components.
Creagh manufactured all pre-cast wall panels, columns and beams for the RE4 project using high-grade recycled sand and aggregate products recovered using our industry-leading wet processing technology.
As well as high-strength and lightweight concrete products derived from CDW, the project also highlighted how plastics, wood fibres, tiles, bricks and more can be returned to good use in the construction of prefabricated and reusable buildings.
Using CDW, the RE4 partners developed a suite of concrete products, components and prefabricated building elements, such as concrete and timber façade panels, load-bearing concrete elements and internal partition walls.
Originally targeting up to 65% (by weight) of recycled materials from CDW in the design and manufacture of both structural and non-structural prefabricated building elements, the project achieved up to 85% of recycled materials, a major achievement in lowering the burden on finite virgin resources.
Importantly, the prefabricated building concept resulting from the RE4 project is 100% reusable, helping to break the unsustainable take-make-waste cycle.
RE4 solutions are both less impactful on the environment and economical; its CDW-derived components and materials cost 20% less to produce when compared to conventional ones and save more than 50% in CO2 emissions.
What the RE4 project has demonstrated is that CDW can be applied to higher value construction applications, including both residential and non-residential buildings. Its results have the potential to completely reimagine how we utilise material in the construction of our future homes and offices, highlighting how recycled sand and aggregate can achieve the same standards of quality and strength as virgin material when tested and, importantly, when supported with the right practices and processing technology.
Our consumption of finite sand resources is directly linked to population growth and soaring urbanisation. By 2050, the world’s population is projected to reach 9.8 billion at a time when 68% of the population will also inhabit urban settings, the equivalent of around 87% of the world’s population today.
As our population grows, so too will the need for sand and aggregate to build more homes, more offices, roads and infrastructure to commute to those offices, places to shop, eat and more.
Through the RE4 project, material recovered from CDW is proven, both technically and economically, as a sustainable solution for building a greener future. CDE has long advocated for CDW and now that its potential is available for the industry to see the challenge remains one of an industry’s willingness to adapt or change.