From Pumping to Deposition (2024-01)¶

3D concrete printing (3DCP) technology has gained significant attention in the construction industry due to its potential to revolutionize the way buildings are designed and constructed. However, successful application of 3DCP requires robust standard test procedures to characterize the printability of concrete. Printability is a measure of workability for a printing material in the 3DCP process, which is characterized by pumpability, extrudability, and buildability. This paper presents a comprehensive review of the test methods that could be used for material characterization during various printing steps, including pumping, extrusion, and layer deposition. The underlying mechanisms relevant to each step, key governing factors, and prediction models are highlighted. The influence of the variation of material and process-induced parameters on the properties of fresh concrete are explained, and the optimum parameters that will lead to an extrudable yet shape-stable printing material are discussed. The recent research on the pumpability, extrudability, and buildability of printed concrete is critically discussed, and future research needs for testing and evaluating 3DCP are identified.