Bond behaviour between 3D printed steel and concrete elements for advanced composite slabs

Additive Manufacturing in Civil Engineering embodies an opportunity to implement components with complex geometries and improved structural performance, while promoting a more sustainable material use and production. In this context, 3D-printed composite slabs represent a viable alternative to the conventional approach. Despite these benefits, documentation and methodologies for such systems remain limited. This thesis investigates the potential of 3D-printed composite slabs, with the primary focus on experimental testing. The research begins with a literature review on additive manufacturing technologies relevant to the study, such as Wire Arc Additive Manufacturing (WAAM), and concrete extrusion by means of 3D-printing systems. Building on this foundation, the thesis covers in detail the fabrication of hybrid steel-concrete elements, including the production of thin steel walls through an additive manufacturing process, and the layer-by-layer concrete extrusion. The core part of the thesis is dedicated to experimental testing, with the purpose of assessing and analysing the bond behaviour between 3D-printed steel and concrete elements. The research underlines the sensitivity to different manufacturing parameters, such as the printing layer orientation or the adhesive application at the interface, which impact performance and bond behaviour. Failure modes are documented in order to capture the aspects affecting structural performance and understand the mechanisms governing the composite action of additively manufactured slabs. Finally, the thesis contributes to the ongoing research on the topic, reinforcing the need for further development of design frameworks and methodologies to ensure a safe application of additive manufacturing in construction.