The latest "Global Resource Outlook 2019. Natural resources for the future we want” presents a potential future circular economy plan that fits within planetary boundaries. The report states that 50% of total emissions is related to material use: mining, transport, production of goods and waste disposal. 90% of biodiversity loss and water stress are caused by resource extraction and processing. From 2000 to 2015, climate change and health impacts from extraction and production of metals doubled. The most used material by far, second to water, concrete has far reaching environmental impacts. In fact, if it were a country the industry would be the third largest carbon emitter after the US and China. Various safety and quality rules in EU and national legislation apply to buildings. Yet the number of EU initiatives that address sustainability issues in this sector are much more limited.
Closed material loops
The built environment consumes 40% of natural resources globally and produces 40% of global waste and 33% of emissions; construction and demolition waste (CDW) making up up to 30% EU waste. But reuse and recycling of material so as to improve circularity can be done in many innovative ways. The efficient use of room space and multi-purpose buildings provide opportunities for new multifunctional furniture and fixtures, and reduces the need for more buildings. New market opportunities related to recycled material-based products also arise in the field of building components. For example, ecological wood stone – a stone made of recycled fibres (Destaclean, 2016), biocomposite products for outdoor construction and cladding (UPM Profi, 2016) or other similar products could also be utilised in public buildings and spaces. Techniques such as recycling materials like ash and soil from nearby construction sites into roads and tarmac in Finland as well as roofing felt waste into asphalt make use of materials while minimising transportation. Currently recycling of doors, windows or frames does not take place at large scale, which could also be explored.
Concrete example: Paris’ recycled public works materials
The City of Paris carries out public works by obtaining local recycled materials. All the finest materials (flagstones, sandstone or granite borders) are recovered from building sites, and once treated, are re-used for refitting or maintenance operations instead of new materials. This demand is formalized in the public procurement contract. Pursuant to Paris public works regulations, penalties are incurred if suppliers fail to deliver natural stone materials to be recycled. In addition to the financial gain, this practice prevents natural quarry mining and the transportation of materials over several kilometers.
Building construction in Berlin
In 2013, the City-State of Berlin launched a pilot project with the aim of encouraging greater reuse of recycled concrete in building construction. A total volume of around 5,400m3 of certified ‘circular economy’ recycled concrete was used in the construction of a slurry wall and building shell of the new life science laboratory building at the Humboldt University. In comparison with concrete made from primary aggregates, the recycled concrete alternative saved 880m2 of virgin gravel, 66% of the energy required for production and transport, and 7% of the associated CO2 emissions. If a product cannot be reused then designing for recycling is the next alternative in making it circular. This means ensuring that the product purchased contains materials that can be easily and effectively recycled into a new product. Alternatively, or in addition to the previous point, the product could be made from recycled content and thus further contribute to resource efficiency.
Zurich: A pioneer is sustainable building material
The City of Zurich is a pioneer in concrete recycling. As part of the European project UrbanWINS, a study trip was organised for practitioners from across Europe to learn about Zurich’s experiences. The European expert group exchanged about how to handle construction and demolition waste, how to procure public buildings that contain recycled concrete and how to involve architects and builders in the process. More information about Zurich’s concrete recycling experience and the study trip can be found here.