Printability and Mechanical Anisotropy of 3D Printed Concrete with Manufactured Sand Derived from Basalt (2024-07)¶

3D-printed concrete (3DPC) technology based on layer-by-layer stacking has received increasing attention owing to its ability to produce customized formwork-free products. In this study, basalt-derived manufactured sand (MS) was used as a replacement for natural sand in 3DPC mixtures. Tests on printability, green strength at varying curing times, hardened mechanical properties, and characterization of the microstructure were conducted. The results demonstrate that the incorporation of MS into 3DPC produces an increase in fluidity and a reduction in unconfined compressive strength. Incorporation of MS enhanced the flexural strength of 3DPC along the printing direction, that is, the interlayer bonding strength, while decreasing its compressive anisotropy from 0.81 to 0.29. This partially compensates for interlayer defects in 3DPC, thereby benefiting for overall performance improvement of structures.