Mix Design of Geopolymeric Formulations for Environmentally Sustainable Structural Applications

Traditional binders, such as Ordinary Portland Concrete, suffer for hygrometric shrinkage and require high production temperature, involving high energy consumption. It is therefore necessary an integrated approach, leading to new solutions for the optimization of the physical and mechanical characteristics of alternative binders, raw materials, by-products and for the implementation of the available technologies. The present work aims to explore the field of binders obtained by geopolymerisation, which has been gaining increasing interest in recent years, due to their lower process temperatures compared to traditional cementitious binders, and their reduced carbon footprint. Geopolymers could represent valuable alternative to products normally used in mortars and concrete production. Their use as a printing material in 3D printing technology is also promising in the field of sustainable construction for the valorisation of wastes from building industry and the production of high quality and readily available products. In this work, a basic geopolymer mix design is proposed to meet the specific requirements dictated by the 3D extrusion printing process. Alkali activated metakaolin and fly ash are considered as binders. Powders of marble waste are selected as aggregate for the achievement of both functional and high aesthetic value in the final products.