Marscrete: A Martian Concrete for Additive Construction Applications Utilizing In Situ Resources

Astronauts in the Apollo Moon landings were provided a prefabricated habitation structure for the short duration on the lunar surface. While the Apollo Lunar Module was designed to house astronauts for only 75 h, a Martian habitat will require a much greater lifespan. For humans to thrive on Mars for any extended period, semi-permanent structures will have to be erected. Such a large and robust habitat would be impractical to transport prefabricated; thus, utilization of local geo-environmental resources is desired. This study presents recent research performed at Northwestern University towards the formulation and characterization of a Martian infrastructure material, called Marscrete. Marscrete is composed, in its simplest version, by sulfur and Martian regolith with a 50-50 mass ratio. Sulfur is plentiful in compounds on and below the surface of Mars, and regolith is a ubiquitous material. Marscrete is the Martian version of traditional sulfur concrete, which is manufactured by melting sulfur and mixing it with sand with approximately a 25-75 mass ratio. Results on compression strength tests, splitting tensile strength, and fracture tests show that Marscrete has significantly better mechanical properties than traditional sulfur concrete and even standard Portland cement concrete. While a generically suitable construction material, Marscrete, when modified with mission-recycled polyethylene fibers, also demonstrates high capabilities for 3D-printing applications—a likely automated construction technique of Martian structures. This paper will discuss the rheological behavior of fresh printable Marscrete, structural performance of the hardened composite, and pose an apparatus to produce 3D-printed Marscrete.