Sulfur concrete made with Martian soil came out twice as strong as its Earthly counterpart, says corresponding author Gianluca Cusatis, an associate professor at Northwestern’s Department of Civil and Environmental Engineering. He thinks this is because the sulfur bonds chemically with the minerals found in Martian soil, whereas on Earth the sulfur only serves as glue for the gravel. Furthermore, since gravity on Mars is one-third what it is on Earth, the strength is effectively tripled.
This material, then, has the strength needed to construct a shelter. But it also solidifies in an hour or less. Even fast-setting concrete takes 24 to 48 hours, Cusatis says, and regular concrete needs up to 28 days to set. That makes sulfur concrete much more attractive for 3-D printing, which is likely to play a role in construction on other planets. Probably most significant, though, is the farm-to-table aspect.
“All the materials are in situ, so there is no need to bring them, which makes the construction also sustainable,” Cusatis says. “You might need a solar panel to use solar energy to melt the sulfur, but that’s about it.”