In a post-COP26 society, architects are faced with the moral responsibility of reaching net-zero carbon waste. In 2016, 62% of the total waste produced in the UK was generated by construction and demolition waste, emitting 3.5 million tonnes of CO2 (CLC, 2021). Circular materials such as glulam and cross-laminated timber offer a cradle-to-cradle solution whereby the material is recycled at the end of its life. Given a blank canvas to construct our built environment with these renewable materials, the carbon emissions would take leaps towards net-zero. In reality, we live in a world comprised of endless ‘concrete jungles.’ Concrete is the most widely used construction material in the UK - as a result, we are faced with the question of what will happen to these buildings at the end of their lifespan?
Concrete Recycling Optimisation with Sika's Innovative reCO₂ver Process
The CO2 uptake of concrete significantly increases after demolition. The crushed fragments absorb CO2 and recarbonate to create a higher quality reusable material (Holcim, 2021). This negates the need to manufacture new cement for concrete structures, which generates 2.8 billion tonnes of CO2 every year (Wired, 2021). Up until recently, limitations to this process meant that secondary concrete was only suitable as base aggregates for road structures and paving’s. However, recent innovations from Holcim and SIKA have introduced potential of recycling demolished concrete for structural purposes. Holcim has developed a technology that improves secondary aggregate by adding untreated CO2 to the old concrete. This expands the potential of reusing concrete for necessary structural purposes in a building such as vertical concrete cores. SIKA have explored a similar process, ‘reco2ver’, that extracts clean aggregates from concrete waste, reducing the cement requirements for recycled concrete and in turn reducing CO2 emissions.
Developments in these technologies offer a promising outlook on the future of existing concrete structures. Not only will producing high quality recycled concrete reduce CO2 emissions in the production of new concrete. It will also cut back on the amount of concrete waste being sent to landfills.
BACK TO TOP