Totalling 750 million tonnes a year, construction and demolition waste (CDW) makes up 25-30 % of all EU waste. Giving metals, wood, glass and concrete a new lease of life, and keeping them out of landfill, is a priority for the EU. To promote this aim, its Europe 2020 Strategy requires member countries to reuse, recycle and recover a minimum of 70 % by weight of non-hazardous CDW. “Our project demonstrated that Europe can achieve that goal by constructing and refurbishing buildings using CDW,” says Sonia Saracino, project coordinator of the EU-funded RE4 project, a consortium of 13 partner institutions in eight countries.
Managing all CDW
“By reusing and recycling CDW materials and structures, we can deliver more energy-efficient buildings and minimise the construction industry’s environmental impact,” adds Saracino, senior project manager at Technologies Design and Materials European Research Centre in Italy. The project developed several innovative solutions to tackle CDW management before, during and after the sorting phases. Results were impressive. For instance, the RE4 project demonstrated how CDW-derived materials and structures can be effectively reintroduced in the production cycles of concrete and timber components, with a replacement rate of 50-85 %. “Our Spanish test site showed it’s even possible to make a prefabricated, energy efficient and fully reusable building for residential or commercial sites,” the coordinator says. For building refurbishment and construction, the project developed five new concrete materials, four new components – blocks, tiles, timber and insulating panels - and four new prefabricated elements. Using secondary raw materials like concrete, bricks, timber and roof tiles, these elements are used for façade panels or internal partition walls. Reversible connections enable complete dismantlement at their end of life.
Smart sorting robot
“We are proud of the on-site, robotic sorting system which achieved recycling rates of up to 95 %. It improves the quality of sorted materials, by focusing on those with high economic value such as sand,” notes Saracino. To fully exploit the CDW recycling potential, the project defined new quality classes for CDW-derived aggregates and identified optimal recycling strategies for each one. These quality classes have been sent to EU standardisation committees with the aim of supporting the development of standards in the field. Saracino adds: “All the project solutions were tested at four different demonstration sites under real conditions, with mock-up buildings in Spain, Italy, United Kingdom and Taiwan. Newly developed RE4 components proved flexible enough to handle different climatic conditions. They can also be used in different types of building found across Europe, as well as those meeting different structural requirements, including earthquake resistance.” The project has attracted broad interest from the technical and general communities, aided by international recognition like the Hans Sauer Award 2020, a best practices booklet and extensive coverage in scientific publications. “RE4 solutions can benefit the green economy and environment. Our new CDW-based materials and components are 20 % cheaper to produce than conventional ones, result in a more than 50 % saving on CO2 emissions, and consume less energy and raw materials,” Saracino concludes.
RE4, building, CDW, construction and demolition waste, design, development, energy-efficient, materials, prefabricated, recycling, refurbishment, reuse