Many research works have recently focused on the development of new green concretes and mortars, aiming to meet the growing interest of reducing construction industry impacts, save raw materials and prevent industrial by-products’ discard. In this contribution many experimental mortars and concretes have been produced and compared in terms of mechanical properties, using both natural and recycled aggregates coming from metallurgical industry (EAF slag), and also conventional binders and supplementary cementing material (carbon fly ash). Then Life Cycle Assessment (LCA) protocol has been used to estimate their sustainability. Between the possible environmental indicators, carbon footprint has been chosen as an overall core indicator, suitable for summarizing the environmental performance of the material. Results indicate that the use of recycled material, both as aggregate and binder, promotes sustainability and allow carbon savings