Reusing old materials in new buildings increases resource efficiency and makes the construction industry less dependent on such scarce resources like sand and gravel. In addition, it contributes to an improvement in the energy balance, especially if the materials are recycled and reused locally.
Many cities are still not aware of the potential and opportunities for recycling construction materials, so there is a long way to go.
Zurich, a pioneer city in recycling concrete
The Kunsthaus, the Zurich Art Museum, is undergoing expansion works. The new project uses mostly recycled concrete and CEMIII/B cement.
But this is just one example of the city’s many new public buildings that include a high proportion of recycled concrete. Zurich, which already has more than 15 years of experience in the use of recycled concrete in construction, wants to use it in all its new constructions. Newer buildings achieve rates of up to 50% recycled concrete in the final product.
The Swiss city is also using recycled materials in road construction and maintenance: up to 30% of recycled concrete is used in the foundation layer, and up to 60% of recycled concrete is allowed and used for the road base, or even up to 80% on sidewalks and places with little traffic.
From demolition to resource
A requirement for successful reuse of construction and demolition waste is proper separation of materials after demolition. In Switzerland, as well as in some other EU countries, this separation is already mandatory.
Years of experience are required to achieve these levels of recycled components in the final product. The recycling process is now at the point that the recycled mineral aggregate mix can be used without having an impact on the quality of the building material. Civil engineering, recycling companies, and other concrete specialists like jpconcrete.co.uk are pioneers in the supply of recycled aggregates for the construction sector. The process produces gravel. Constructors can replace around half of the natural sand and gravel normally used to make concrete with the new recycled gravel.
While the recycling of construction and demolition waste responds to the problem of scarce resources, it also faces new challenges, such as the problem of CO2 emissions resulting from the production of concrete. Therefore, to achieve a future in which carbon emissions are close to zero, we must seek new solutions and continue to examine new materials.