3D Concrete Printing in the Waste Hierachy: Reduce, Reuse and Recycle

Reduce, Reuse, and Recycle are core principles of the waste hierarchy. This scoping review evaluates the sustainability of 3D concrete printing (3DCP) within the circular economy framework, focusing on these principles. A systematic analysis of 143 papers, divided into three groups focusing on Reduce, Reuse, and Recycle, evaluates developments, constraints, opportunities, and requirements for 3DCP. For Reduce, 3DCP provides significant benefits in material reduction and structural optimisation through its geometrically flexible nature, on condition practical constraints, such as overhang angles and printing system limitations, are addressed. For Reuse, functional examples of reusable 3DCP elements have been successfully created, however, the potential for 3DCP in reuse is reduced by durability concerns and standardisation efforts. For Recycle, high cement content poses environmental challenges, yet advances in incorporating recycled aggregates and supplementary cementitious materials demonstrate viable pumpable, extrudable and buildable mixes with sufficient long-term strength for structural applications. These advancements position 3DCP as a transformative technology for minimizing waste and promoting resource efficiency. Nevertheless, challenges remain, including the need for standardized testing protocols, robust regulatory frameworks, and improved durability to fully realize 3DCP’s circular economy potential. This review, among the first to systematically apply the waste hierarchy to 3DCP, underscores its promise for advancing Reduce and Recycle principles, with Reuse requiring further development.