Innovative development of geopolymer-based lunar high strength concrete for sustainable extra-terrestrial construction using large-scale regolith simulants

The quest for viable construction materials for lunar bases has directed scientific inquiry towards the lunar in-situ resource utilization (ISRU), notably lunar regolith, to synthesize concrete. This study develops an innovative lunar high strength concrete (LHSC) utilizing lunar highlands simulant (LHS-1) and lunar mare simulant (LMS-1) as both precursors and aggregates within the concrete matrix. Mixtures were cured under the conditions simulating the lunar surface temperatures, enabling an evaluation of properties such as flowability, unit weight, compressive strength, modulus of elasticity, and microstructure patterns. Test results indicated that the LMS-1 mixtures exhibited a better flowability and higher unit weight as compared to LHS-1 counterparts. Moreover, the highest 28-day strength was 106.7 MPa and 98.7 MPa for LHS-1 and LMS-1 derived LHSC, respectively. Microstructure analysis revealed that under the identical simulant additions, LHS-1 mixes exhibited superior structural compactness with denser amorphous gels and fewer microcracks. In addition, it possessed a lower Si/Al ratio and diffraction peak of calcite, along with a greater Ca/Si ratio and hump intensity of amorphous gel phases. The development of this cement-free LHSC, incorporating up to 80 % large-scale lunar materials in the total binder mass, plays a critical role in advancing ISRU on the Moon, thus boosting the viability and sustainability of future lunar construction and habitation while significantly reducing transportation and fabrication costs. • Innovative LHSC utilizing large-scale lunar soil simulants is developed. • The highest compressive strength for LHS-1-derived LHSC is 106.7 MPa. • LHSC with LHS-1 has better compactness and fewer unreacted simulant than LMS-1. • LHSC with LHS-1 possesses lower Si/Al and higher Ca/Si ratios than LMS-1. • LHSC containing up to 80 % lunar soil plays a critical role in advancing ISRU on the Moon.