Sustainable Geometries (2025-12)¶

3D printing has become a leading trend in research and development, playing a crucial role in advancing the Construction 4.0 industry. Aligning with future sustainability goals by increasing productivity and minimising material waste, it is seen as a promising solution for sustainable construction. Concrete, valued for its availability, strength, and adaptability, is a primary material in 3D printing worldwide. However, its high usage of cement-based material, whose production leads to significant CO2 emissions, drives up its environmental impact substantially. Enhancing the thermal efficiency of 3D printed concrete structures offers a pathway to mitigate this impact. Literature indicates that thermal optimisation can be achieved by modifying structural topology or geometry. This review paper examines thermal optimisation in uninsulated 3D printed concrete walls by comparing 13 topologies referenced in the literature. These configurations were compared based on their geometric properties such as wall thickness and void percentage, as well as their U-values, to identify the primary factors affecting their thermal performance. In the cases analysed, U-values ranged between 0.61 and 3.485 W/m2K. Among them, the diamond, cob, and double-rowed configurations—featuring smaller air cavities, longer heat path distances, and more branches and intermediate barriers—demonstrated the best thermal performances within their respective studies. While findings indicated that majority of the studied topologies might need additional insulation to comply with several European U-value standards for new building envelopes, optimising wall geometry should remain to be pursued to reduce dependence on additional insulation measures.