DELRA (2026-02)¶

The emergence of concrete 3D printing (3DCP) has enabled the fabrication of geometrically complex and material-efficient structures, offering substantial benefits in terms of sustainability, automation, and design flexibility. However, 3DCP remains constrained by the layer-by-layer deposition process, where frequent print-head stops and starts—common in complex geometries—can lead to material inconsistencies and structural vulnerabilities. While existing research highlights interlayer bonding and anisotropy as general challenges, there is a specific lack of path-planning strategies capable of maintaining continuous material flow for intricate lattice structures. This study introduces a heuristic-based algorithm, DELRA, specifically developed to generate continuous, optimised print paths for complex lattice structures, addressing the current lack of specialised solutions in this domain. The structural performance of lattice elements printed using DELRA is compared with conventional crossing and abutting printing path strategies. Experimental results, validated against numerical models, demonstrate that DELRA maintained near-ideal structural integrity with only a 0.4% loss in flexural performance. In contrast, the crossing and abutting paths exhibited significant performance reductions of 9.15% and 16.23%, respectively. These findings highlight the mechanical improvements provided by DELRA, resulting from the continuity and uniformity of the extrusion process. Thus, by bridging the gap between structural optimisation and continuous print path planning, this work advances the practical realisation of complex lattice geometries in 3D concrete printing, contributing to more efficient, reliable, and high-performance construction solutions.