Engineering Properties of Magnesium Phosphate Cement Lunar Soil Concrete Under Vacuum Conditions and Its 3D Printing Application for Lunar Dome Model (2025-08)¶

To tackle the extreme environmental challenges and sustainable extraterrestrial construction material supply issues for lunar base development, this study fabricated a magnesium phosphate cement-based lunar soil concrete (L-MPC-LSC) following in-situ resource utilization (ISRU) principles and integrated it with 3D printing construction technology. This paper investigates the effects of lunar soil (LS) content on the microstructure and mechanical properties of L-MPC-LSC under both standard atmospheric and simulated lunar vacuum conditions, while evaluating the engineering feasibility of 3D-printed lunar dome model for lunar surface construction. X-ray diffraction (XRD) and scanning electron microscopy (SEM) show that LS enhances the mechanical properties of L-MPC-LSC by simultaneously modulating Dittmarite and K-struvite crystallization with providing a micro-aggregate packing effect. When the lunar-soil-to-magnesium-oxide mass ratio (LS/M) ranged from 0 to 3, Dittmarite crystals dropped from 42.43 % to zero. K-struvite crystals first increased and then decreased, peaking at 45.80 % the changes in the microstructure lead to a nonlinear increase in the contribution rate of LS to the compressive strength of the material (67.9% to 77.3%). Vacuum curing caused rapid dehydration, reduced K-struvite crystals, greater porosity, and 19-52 % strength loss, yet the LS/M = 3 specimen still achieved 4.1 MPa after three days—surpassing the minimum requirement for lunar-base structures and yielding 60 % ISRU. Printing trials with a lunar dome model confirmed excellent printability and the feasibility of robot-assisted construction, offering an integrated material-structure-process solution for future lunar habitats.