Preliminary Experimental Investigation on the Material Properties of a Lightweight Foamed Concrete via 3D Printing

Abstract. The integration of Foamed Concrete (FC) in 3D Concrete Printing (3DCP) processes represents a promising and forward-thinking strategy within the construction sector. This approach aims to combine the unique advantages of FC – such as lightweight nature, enhanced sustainability, and multifunctionality – with the efficiency and precision offered by automated construction technologies. Despite its potential, the use of FC in 3DCP remains largely underexplored due to the additional challenges posed by the distinct rheological and physical characteristics of FC, which affect printability, buildability, and ultimately the per-formance of hardened 3D-printed elements. Nevertheless, a deeper understanding of this research domain could facilitate the development of strategies to improve control over these factors, thereby enabling the successful use of FC in 3DCP. The present study investigates the application of a lightweight foamed concrete with a dry density of approximately 760 kg/m3 in a medium-scale 3DCP process. Some properties of the printed material were evaluated, including mechanical strength (flexural and compressive strength) and qualitative microstructural char-acteristics. The obtained results were compared with those for conventionally cast foamed concrete specimens, and, for 3D-printed specimens, two alternative cur-ing conditions were proposed. The findings highlight the main effects of 3DCP on hardened-state material performance and underscore key aspects – such as air-void shape stability and moisture control in air curing conditions – that require further optimization and control to enhance material performance in view of future applications of this emerging technology.