Low binder content bricks: a regolith-based solution for sustainable surface construction on the Moon

This work proposes a composite construction material made by a blend of lunar regolith and thermoplastic binders in dry powder form. This solution offers advantages over regolith sintering or melting by requiring lower power consumption and simplifying the manufacturing process. However, its sustainability depends on minimizing the content of the binder material. Drawing from validated concepts used on Earth, such as polymeric concrete and compressed Earth bricks, this paper suggests that binder optimization can be achieved by simplifying and streamlining the manufacturing process, targeting parts with predefined shapes. Standardized elements like bricks or tiles ease production and assembly automation, especially when incorporating interlocking features, simplifying the payload concept transition. After drafting the process with a minimum number of basic steps, this work studies the effects of some process parameters to minimize the weight percentage of the matrix while maintaining reasonable mechanical properties. The compressive and the flexural strength are the targets of an orthogonal array Design of Experiment. Through comparison with reference values for civil engineering, the process demonstrates promising results within an organic phase as low as 10 wt%. A manufacturing process easily scalable to larger-sized products is proposed for a regolith-rich composite material. Adjusting the binder weight percentage, compaction pressure, and regolith grain size improves the mechanical properties. A minimal binder allows for reaching possible compression and flexural strength requirements for lunar construction.