Towards sustainable concrete

Every step in the life cycle of a material leaves a footprint on our planet. From the extraction or harvesting of raw materials to their conversion into familiar products, and then from the daily use of such products to their disposal, each phase has to be managed responsibly to avoid the risks related to the depletion of resources, increase in CO2 emissions and waste accumulation. Due to their large worldwide consumption, the environmental impact of some materials is particularly critical. For instance, concrete is one of the most important construction materials used in houses and infrastructure, where it is usually combined with metal alloys for structural reinforcement and decorative purposes. Metals are also used in a wide range of applications, from kitchen tools to vehicles and rocket engines. We asked experts in concrete research and metallurgy their opinions of the critical aspects related to the sustainable production, use and disposal of these materials, and their views on the strategies that are being adopted and may be further explored to decrease the environmental burden of these commodities. In the case of concrete, partial or complete replacement of one of its components, Portland cement, is essential to cut the CO2 emissions and energy consumption caused by its production. Defect engineering of metal alloys may be a viable approach to tune the mechanical response of structural materials without increasing the number of elements included in their composition.