Current Developments in the Application of Extrusion-Based 3D Concrete Printing (2024-11)¶

Automation technology for construction applications is gaining significant attention, contributing to economical and sustainable construction practices. Extrusion-based 3D concrete printing (3DCP) is one of the widely adopted automation processes allowing to built intricate geometries with a freeform construction method. However, despite its potential, the large-scale application of extrusion-based 3DCP still poses significant challenges in developing high-strength, sustainable printable concrete mixes and feasible reinforcement methods. This study discusses the current developments in sustainable printable concrete mixes, assessing their pumpability performance and exploring the in-process reinforcement methods for 3DCP structures. Recent advances in alkali- activated printable mixes using fly ash and slag instead of cement have paved the way for high- strength sustainable printable mixes. Moreover, employing vibration-induced active rheology control during pumping enhanced the lubrication layer properties, thereby improving the pumping efficiency by reducing the pumping pressure and mitigating the clogging issues along the pipeline. Apart from the advancements in printable mixes, the in-process reinforcement method utilising textile reinforcement and recycled plastic fibres has shown promise in improving the mechanical properties of 3DCP structures. Incorporating plastic fibres significantly improved the flexural and compressive strength of 3DCP elements, along with improving thermal resistance. This paves the way for building energy-efficient and aesthetically pleasing structures. Moreover, incorporating high-strength flexible textile reinforcements (like AR-glass, carbon and basalt) improves the flexural and tensile capacity of 3DCP structures and facilitates the construction of slender structures, thus reducing the overall carbon footprint. These advancements in sustainable concrete mixes and reinforcement methods expand potential of 3DCP for large-scale construction, offering opportunities for efficient and aesthetically pleasing structures.