Techniques and strategies in extrusion based 3D concrete printing of complex components to prevent premature failure

Extrusion based 3D Concrete Printing (E-3DCP) is a rapidly growing method of construction due to its ability to manufacture bespoke architectural and structural elements without incurring the additional time and costs typically associated with the manufacturing of the formwork of these components. However, Complex geometries such as overhangs, bridges, and cantilevers pose significant challenges to E-3DCP, increasing the risk of premature failure during 3D printing and complicating the integration of longitudinal reinforcement. In response to these challenges, researchers have developed various techniques and strategies to mitigate these complexities and failures. This paper provides a comprehensive review of these methods, evaluating their advantages and disadvantages, and identifying research gaps in the current literature.