In the quest to establish sustainable habitats on the Moon, researchers have made a significant stride in developing construction materials that can withstand the harsh lunar environment. Zihan Zhou, a researcher at the School of Urban Rail Transportation, Shanghai University of Engineering Science, and his team have published a study in the journal *Case Studies in Construction Materials* (translated as “Case Studies in Building Materials”), focusing on the dynamic mechanical properties of lunar regolith-based geopolymer. This research could have profound implications for the energy sector, particularly in the development of extraterrestrial infrastructure.
The study utilized a high-fidelity lunar regolith simulant, GCD-2, which closely mimics the physicochemical properties of lunar samples retrieved by the Chang’e-6 mission. The team synthesized a lunar regolith-based geopolymer (LRG) using a “one-part” method, combining a dry mixture of GCD-2 and solid sodium silicate with water. The dynamic mechanical properties of the LRG were then evaluated using the Split Hopkinson Pressure Bar (SHPB) apparatus.
Zhou and his team systematically investigated the influence of precursor Ca/Si and Al/Si ratios in the lunar regolith simulant, as well as lunar thermal cycling, on the dynamic compressive strength and energy absorption capacity of the LRG. “We found that increasing the Ca/Si ratio to 0.35 markedly enhanced the degree of geopolymerization, promoting the formation of abundant C-(A)-S-H gel and resulting in a denser matrix with significantly improved dynamic elastic modulus and peak compressive strength,” Zhou explained.
The researchers also discovered that adjusting the Al/Si ratio to 0.50 facilitated the crosslinking of [AlO4] units within the (C)-N-A-S-H gel network, further improving the dynamic mechanical performance. However, excessive Al/Si ratios hindered geopolymerization kinetics and increased porosity, thereby reducing the compressive strength of the LRG. “There is a synergistic effect between Ca and Al that intensifies geopolymerization and yields a highly compact microstructure,” Zhou noted.
The study identified the optimal time window for mixing and casting LRG on the lunar surface to be within 100 hours prior to the high-temperature phase of the lunar daytime. This finding is crucial for planning construction activities on the Moon, ensuring that materials are used efficiently and effectively.
The implications of this research extend beyond lunar habitats. The development of impact-resistant construction materials could revolutionize the energy sector, particularly in the construction of offshore wind farms, nuclear power plants, and other infrastructure projects that require materials capable of withstanding extreme conditions. As we look to the future, the insights gained from this study could pave the way for innovative construction materials that are not only durable but also sustainable.
In the words of Zhou, “This research provides both theoretical insights and practical guidance for the development of impact-resistant construction materials to support sustainable extraterrestrial habitat engineering.” As we continue to explore the possibilities of space habitation, the work of Zhou and his team serves as a beacon of innovation and progress.