Next-Generation Green Construction (2025-12)¶

The rising demand for sustainable construction has spurred interest in 3D-printed concrete (3DPC), a technology enabling automated, material-efficient, and geometrically flexible building solutions. Conventional 3DPC, however, relies heavily on Portland cement, contributing significantly to carbon emissions. 3D-printed geopolymer concrete (3DPGC), synthesized from industrial and construction by-products, has emerged as a low-carbon alternative with substantial environmental benefits. This review critically consolidates recent advances in 3DPGC, focusing on the influence of waste-derived precursors on rheology, buildability, mechanical performance, microstructure, and sustainability metrics. Key insights reveal that printability and structural integrity are highly sensitive to mix composition, rheological tuning, and particle packing. The incorporation of supplementary materials such as slag, ordinary Portland cement, or waste glass powder modulates yield stress, viscosity, and interlayer bonding, directly impacting shape retention and interlayer adhesion. Moderate reactive filler content promotes geopolymerisation and microstructural densification, whereas excessive inert additions reduce performance. Mechanical behavior exhibits pronounced anisotropy due to interlayer weaknesses, with strength predominantly arising from amorphous gel formation.