Komkova, Anastasija; Andersen, Birgitte Holt; Habert, Guillaume

An increasing global population leads to a higher degree of urbanization and growing demand for construction materials. As concrete is the most widely used material in the construction sector, its production continues to grow, leading to depletion of natural resources and environmental degradation. The production of Ordinary Portland Cement (OPC), which is the most conventional binder for concrete, contributes to approximately 8% of global anthropogenic CO2 emissions. In order to reduce global CO2 emissions, alternative binders, such as alkali-activated materials (AAM) are being developed. The AAM technology allows utilization of industrial by-products (ground granulated blast furnace slag, fly ash) and waste materials (municipal solid waste incineration ashes, glass fiber waste, sewage sludge ashes, mineral wool waste) in concrete production, thereby contributing to circular economy principles. The LCA of AAMs shows that open-loop recycling of waste materials in AAM concrete leads to up to 70% lower CO2 emissions, compared to cement concrete. However, in order to match the growing demand for sustainable concrete with the supply of AAMs solution, it is important to examine the regional availability and potential supply of industrial by-products and waste materials that can be used as inputs in AAM concrete production. Assuming that the annual production of fly ash and slags in Europe will decrease in the future due to the projected phase-out of coal power plants and the decreasing domestic production of steel, in this study is examined the availability of alternative resources. The LCA approach is combined with the assessment of stocks and flows of waste materials to examine the sustainability of AAM concrete technology within the circular economy. The results will indicate the potential for industrial symbiosis among the relevant value chains.