Changing the Paradigm of Structural Concrete Construction: 3D Printing Application to Arch Beams

A paradigm change in the construction sector is represented by the switch from traditional concrete construction to extrusion-based 3D concrete printing (3DCP), which is motivated by the need for automation, geometric freedom, material efficiency, and less environmental impact. However, because of its anisotropic behaviour, which results from the multilayer deposition method and the quality of interlayer bonding, 3D-printed concrete’s structural use is still difficult. In the present research, compressive and flexural tests were used to characterise the mechanical characteristics of both binders before and after printing. This allowed for the evaluation of the impacts of extrusion and layer orientation on strength development. A 3D-printed arch beam made entirely of CEM I 52.5 R was evaluated under three-point bending at the structural level. In order to minimise tensile demands and lessen the impact of anisotropic flaws, the arch design was chosen to align internal force flow primarily in compression. Extrusion can improve mechanical performance in high-clinker systems; however, anisotropy has a considerable impact on flexural performance depending on loading direction and layer orientation, according to the results. When anisotropy is appropriately taken into consideration, low-carbon binders’ behaviour remained within acceptable ranges for structural applications, despite their decreased early-age strength. This study also shows an application in the structural design of 3D-printed concrete arches, using classical finite element tools, normally used by structural designers.