Try building a house without any of the materials mere Earthlings use to build houses.
That’s the challenge facing astronauts as they move forward with colonizing Mars. They’ll either need to bring materials with them, which will be wildly expensive and generally unreliable (what if you need a spare part?), or make use of the Red Planet’s rugged, inhospitable terrain. NASA recently rewarded a design for a 3-D-printed ice house as a promising use of Martian water deposits to make a safe, radiation-proof habitation. But water will be scarce and better used for sustaining the lives of the space settlers.
Researchers from Northwestern University have an alternative proposition: sulfur concrete. Most Earth concrete, the primary building block of modern construction, requires water mixed with cement and gravel. Sulfur, which is widely available on Mars, can take the place of water and bind the concrete together. In a study submitted to Construction and Building Materials last month and posted online, the scientists tested out different mixes of simulated Martian soil with sulfur and found the optimal concrete recipe for a sturdy Red Planet abode.
Sulfur concrete has been around for decades—it’s been used for pipelines and artificial reefs, the study notes—so the methodology was relatively straightforward. Simulated Mars soil, which has the same chemical and mineralogical properties as real Mars soil, is readily available for purchase. (Time to start that Martian terrarium you’ve always dreamed of!) So the researchers heated it up with sulfur in different ratios, then they stress-tested the concrete, both physically and through computational analysis.