Let's get empirical. The good news is research into martian concrete has been done.
Researchers think regolith on Mars could serve as a replacement for concrete components. The Mars rovers have used gas chromatography, mass spectrometry, and laser spectrometry to determine the composition of martian soil. Mars regolith is mostly silicon dioxide and ferric oxide, with a fair amount of aluminum oxide, calcium oxide, and sulfur oxide. The composition varies from place to place on the planet’s surface because of variability in asteroid collisions and the weathering by wind and water, in ancient oceans and in some modern water flows. But no spacecraft has returned to Earth with actual samples of the material.
But will it be easy? Perhaps not. There's a lack of water.
On Earth, concrete cures and strengthens thanks to the chemistry of cement, which consists of limestone and water. However, most limestone on Earth was formed by sea creatures, which Mars never had. Martian soil has the calcium and carbon found in limestone, but the elements are scattered around the planet. And Mars has water but it’s not plentiful. “It’s going to be a long time before we can produce cement on another planet,” says Gianluca Cusatis, a professor of civil and environmental engineering at Northwestern University.
However, sulpur can be used as an alternative.
What Mars does have is a lot of sulfur in its soil, and molten sulfur has been used to bind some concrete on Earth. To test the possibility of using it to make martian concrete, Lin Wan-Wendner, while a Ph.D. student in Cusatis’s lab, melted sulfur and mixed it with JSC Mars-1a in a ratio of 1:3, the same recipe used for sulfur concrete on Earth. She then subjected the concrete to standard tests of its strength under compression, bending, and splitting.
Using Earth sand, that recipe produces a compression strength of about 30 megapascals, similar to that of cement-based concrete. But the simulated martian concrete was much weaker, which may have been because the material was more porous than the Earth version, Cusatis says. More porous concrete is usually a result of larger particles in the sand.
Fortunately, this problem of weaker sulpur-based concrete can be overcome.
When Wan-Wendner, now a researcher at the University of Natural Resources & Life Sciences, Vienna, and colleagues tried a sulfur-to-sand mix of 1:1 and compressed the mixture to break down grains and drive out air bubbles, the resulting concrete had a strength of 60 MPa, twice as strong as standard concrete. Sulfur-based concrete also hardens quickly, in the time it takes for the mixture to cool. Regular concrete takes 28 days to completely cure and gain its full strength. The quick setting may be an advantage for 3-D printing, Cusatis says, because it means each layer of the material will almost immediately be strong enough to hold the layer printed on top of it.
This isn't the only way to make martian concrete.
Another proposal for martian building materials eliminates a binder altogether. UCSD’S Qiao discovered that he could turn a regolith simulant into bricks by simply compressing the material rapidly. The soil is full of iron oxide and oxyhydroxide particles about 25–45 μm across. “If you compress the soil grains at high enough pressure, you are going to cleave those iron oxide nanoparticles,” Qiao says.
The reason for this stronger martian concrete is considered to be:
The breakage gives the nanoparticles clean, flat surfaces. Under further pressure, they rotate so that the tiny, freshly cleaved facets press against each other and form a bond. Qiao believes the nanoparticles bind to each other through a mix of van der Waals forces and atomic bonds, though he hasn’t tested that assumption. What’s more, the binding happens in just about a millisecond under 400 MPa of pressure. That is about the same amount of pressure produced by dropping a hammer on the soil, Qiao says. And that is essentially what his team did.
Similar processing can be used on other forms of martian soil too.
Another type of soil common on Mars is a sedimentary, claylike material formed in ancient oceans. It has the same chemical composition as other regolith, but weathering by water long ago means it has a fine-grained structure with no nanoparticles and an electrostatic surface charge. Qiao found that compacting layers of a replica of this dry Mars clay under high pressure also created a solid material. The layers of the clay became naturally aligned under pressure so that electrostatic forces held them together. But rather than striking the material rapidly, the researchers slowly squeezed the clay layers together. The two soils produce “similar strong solids,” Qiao says.
Other methods for making concrete have been considered. This involves 3D printing techniques.
In Mueller’s lab at NASA, researchers are testing polymers as a binder for the regolith. It should be possible to manufacture polymers, such as high-density polyethylene, on Mars using carbon dioxide from the atmosphere and hydrogen from water in the soil, Mueller says. With a 3-D printer, his lab built a dome 1 m in diameter out of their simulated Mars concrete to show what they hope to do on a larger scale. Of course, 3-D printing with concrete is challenging, Mueller says. The deposited material has to be thick enough to hold its shape during the printing process but thin enough that it doesn’t clog the machine or dry so fast that it cracks. “The trick is getting a material that has the right consistency so that it can be extruded and it can cure,” he says.
Mueller would like eventually to skip the polymer binder and instead harden the soil by sintering it—that is, heating and compressing it until it becomes solid. That should be possible using a laser beam, a solar concentrator, or a microwave system. But until researchers develop that technology, they’re using the polymer binder to test their 3-D-printing ideas.
In conclusion, there are number of possible proposed methods of making concrete on the planet Mars. Research has already been conducted. The results are promising. presumably more research will be needed. There are questions about durability that may need to eb resolved. It is feasible concrete will be made from regolith on the Red Planet. As shown by preliminary research.
Neil Savage, "To build settlements on Mars, we’ll need materials chemistry," Chemical & Engineering News, Volume 96, Issue 1, pp. 16-18.
(Issue Date: January 1, 2018 ; Web Date: December 27, 2017).
Lin Wana, Roman Wendner b, Gianluca Cusatis, "A novel material for in situ construction on Mars: experiments and numerical simulations," Construction and Building Materials, Volume 120 (2016) pp. 222–231.
Nilesh Biswal, Rushikesh Badnakhe, Sanket Sawarkar, "Construction Material on Mars," International Journal for Scientific Research & Development, Volume 5, Issue 10, 2017