Additive Manufacturing of Sustainable Clay Bricks: A Critical Review of Technologies, Challenges, and Opportunities

Conventional fired clay brick production is energy-intensive and associated with significant carbon emissions due to kiln firing and mass molding processes. In this context, extrusion-based additive manufacturing (AM), particularly Direct Ink Writing (DIW), has emerged as a potential alternative for shaping clay-based building units, enabling reduced material waste, the use of locally sourced clays and recycled additives, and the fabrication of complex geometries with enhanced thermal and structural performance. However, despite these advantages, the application of AM to clay bricks remains limited, as key challenges persist in terms of material rheology, interlayer bonding, production scalability, and the continued need for high-temperature firing, which constrains its environmental benefits. This study presents a scoping review of AM technologies applied to clay brick manufacturing, focusing on their technical feasibility, material requirements, and sustainability implications in comparison with conventional processes. Furthermore, current research trends are analyzed to identify existing gaps, particularly regarding industrial scalability and life cycle assessment (LCA), and to outline future research directions required for the development of a new generation of sustainable clay bricks.