A road map to find in 3D printing a new design plasticity for construction- The state of art

Recent years are showing a rapid adoption of digital manufacturing techniques to the construction industry, with a focus on additive manufacturing. Although 3D printing for construction (3DPC) has notably advanced in recent years, publications on the subject are recent and date a growth in 2019, indicating that it is a promising technology as it enables greater efficiency with fair consumption of material, minimization of waste generation, encouraging the construction industrialization and enhancing and accelerating the construc-tive process. This new building system not only gives an optimization of the building process but provides a new approach to the building design materiality. The direct connection between design and manufacturing allows the reduction in the number of the various construction phases needed. It is opening a new and wide range of options both formal and chromatic in customization, avoiding complex formworks, reducing costs and manufacturing time. The cre-ative process has a strict and direct link with the constructive process, straightening design with its materiality. Cement-based materials lead the way, but new alternatives are being explored to further reduce its carbon footprint. In order to leverage its sustainability and enhance the system capacity, initiatives are being pursued to allow the reduction of the use of PC. Geopolimers are taking the first steps in 3DPC. Construction and Demolition Waste (CDW) materials are used to substitute natural aggregates. Even soil is being explored has a structural and aesthetic material. These research trends are opening a wider range of possibil-ities for architecture and design, broadening the spectrum of color, texture, and formal variations. The concern about textures and colours is not yet evident in many the structures already printed, opening the opportunity for future research. More can be done in the mixture and formal design of this building system, "discovering" other raw materials in others waste. This article aims to make a critical review of technologies, materials and methodologies to sup-port the development of new sustainable materials to be used as a plastic element in the printed structure. A roadmap of 3D printing for construction is presented, and an approach on mix design, properties in the fresh and hardened state, highlighting the possibilities for ob-taining alternative materials are pointed. With this review possible directions are presented to find solutions to enhance the sustainability of this system discovering "new" materiality for ar-chitecture and design.(c) 2022 Higher Education Press Limited Company. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).