Brick from soil simulating Martian soil: stronger than concrete

In the future, can we use this brick to build a base on the red planet?

If you think it's hard to build a house on Earth, try building a house on Mars. Every kilogram of material transported to the red planet will cost thousands of dollars, so scientists want to build future bases from materials originating in the planet itself - namely stellar dust Fire . But that is more difficult than we thought.

The temperature on Mars is very low, making 3D printing with wet concrete a challenge. We can melt the dust and rock on the surface into lava and then pour it into the mold, or melt that dust with a laser, but both of these methods will lose a lot of energy. Or another way is to bond with dirt by polymer, but it will cost a lot of money to transport polymer to Mars.

A new strategy proposed in the Nature Publisher Science Report is intriguing because of its simplicity: if we can use Martian soil to make super strong bricks? Researchers at the University of California, San Diego tested the method. Just piston presses and some soil simulate the characteristics of Mars dust, mechanical engineer Yu Qiao and his colleagues made bricks with a size of 5 cents more than reinforced concrete. .

Yu Qiao's team unknowingly discovered this unique characteristic. At first, they experimented with producing Martian bricks with a polymer adhesive. To reduce trips in the hypothesis between Earth and Mars, they gradually lowered the amount of binder in brick samples to see the minimum needed. "When we reduce the amount of binder to 0, there is still some certainty. In our opinion, the material itself has something interesting".

Bricks made from Martian soil can be stronger than concrete.This brick was broken by researchers who tested it beyond its failure threshold.(Photo: Jacobs Technical School / University of California, San Diego).

When pressed by force equal to the force exerted by the rotating hammer, the iron oxide particles in the soil simulate - the particles that bring out the characteristic red color of Mars - seem to be bound together. It is this property that makes bricks surprisingly solid.

Planetary physicist Philip Metzger, who specializes in Mars soil mechanics at Central Florida University, said the results were interesting, but also warned that real soil on Mars could have other reactions.

Qiao said: "It is also our concern."

Simulation materials used by Qiao have been developed by NASA and are considered one of the best Mars soil simulations. However, its composition differs from what we have seen on Mars - for example, the simulated material has three times the amount of aluminum oxide, and six times more titanium oxide than the dust and rock on Mars. And this land is taken from Hawaii a lot of rain, where the weather states affect the particle size and minerals are significantly different from our dry and icy neighboring planet. In other words, Metzger said: "It looks like Mars, but there's no guarantee that it reacts like Mars."

Ideally, the spacecraft will one day bring back real soil from the red planet so that scientists can learn and test the properties of the soil, but in reality there is no such mission. so mentioned. Until then, or until it is possible to send a brick-making robot to Mars, the best thing that Qiao and his team can do is experiment with a material that is not exactly the same as the chemical composition. as well as particle size and shape. Qiao said he and his team will continue their efforts.

And there is another potential limitation, Metzger said: "Iron oxides that connect bricks together are only found in a thin layer on the surface of Mars, which will make collecting enough substances It is very difficult to build a shelter for humans in most places on Mars, only where the layers of red dust overlap with hundreds of centimeters of depth are suitable for creating out the bricks from the dust layer ".

Metzger (who worked closely with NASA's aeronautics and space agency) said although the agency is more likely to invest in a technology that can be used anywhere on Mars and certainly brings effective, the research results of Yu Qiao and colleagues are still applicable on the surface of Mars.

According to Metzger, the strategy may not be good enough for NASA, because it limits the location of bases but for the famous technology entrepreneur Elon Musk, this may be the perfect solution.