Identifying barriers and enablers for emerging value chains in open-loop mineral wool waste recycling within the construction sector

Abstract

Global objectives to mitigate climate change, minimise waste, and ensure the efficient use of resources require urgent actions in multiple sectors, including construction and buildings. Currently, rock wool and glass wool are widely used as insulation materials in the building stock across Europe, while in multiple countries are still landfilled at their end-of-life. Within a recent research project, mineral wool waste has proved to be recyclable as a precursor in an alternative binder to carbon-intensive conventional cement, such as alkali-activated materials (AAMs). This open-loop recycling of mineral wool in AAMs is associated with the creation of new value chains within the circular economy that can trigger symbiotic relationships between urban areas and industries. Stakeholders who produce mineral wool waste–based alkali-activated construction materials at a pilot scale in 5 European countries were interviewed to evaluate their environmental, economic and social performance using selected circular economy indicators. Strengths, weaknesses, opportunities, and threats (SWOT) analysis was applied to identify common trends across pilot-scale productions and potential industrial up-scales. While common barriers include limited economic viability at the pilot scale, which can be addressed through industrial upscaling with optimised supply chains, there is also variability in consumer acceptance of waste-based materials across countries. Finally, potential solutions to the identified barriers along each step of the value chain are proposed. The results show that combined actions of industry, cities, and policymakers are required to overcome barriers and nudge the transition towards a circular economy. This can be achieved by using economic incentives to enhance the cost-competitiveness of alternative construction materials, promoting green public procurement, and raising public awareness.