Influence of the construction process parameters on the mechanical performance and durability of 3D printed concrete (3DPC): A systematic review

The parameters of the 3D printing construction process are interdependent variables that significantly influence not only the mechanical performance of 3D printed concrete (3DPC), but also its long-term durability the overall life cycle. Despite the growing interest in this field, no systematic review has yet been conducted to specifically evaluate the influence of these parameters on both mechanical behaviour and durability. To address this gap, a systematic review was performed using data extracted from the Web of Science, Scopus, and ScienceDirect databases. Based on the collected literature, key construction process parameters were identified, including the printing interval between layers (PIBL), printing velocity (PV), pumpability, nozzle geometry (NG), and layer geometry (height and width). The findings reveal that variations in printing systems substantially affect the optimization of process parameters. Moreover, while mechanical properties have been extensively studied, their relationship with durability has often been overlooked. The most influential parameter affecting durability was identified as the printing interval between layers, followed by printing velocity. Notably, these parameters are often adjusted based solely on the fresh-state performance of the material. To reinforce the findings, an experimental demonstration was conducted by the authors with a 3DP-ECC, highlighting the practical implications of optimizing these process variables. This study provides a scientific foundation for future studies and encourages both academic and industrial researchers to consider the durability-performance correlation in 3DPC structures.