"All we need now are a new generation of Martian architects to design buildings made of Martian concrete that will be suitable structures for humans to live and work in," concludes the MIT Technology Review in their report on a new type of concrete designed for use on Mars.
Developed by scientists led by Lin Wan at Northwestern University, this "Martian concrete" is just one of many scientific developments that will be required for the increasingly popular goal of sending humans to, and eventually colonizing, the Red Planet (apparently the un-colonized Moon is already old hat - just ask Matt Damon).
Reasoning that when we finally do colonize Mars, water will be one of our most precious resources, the team from Northwestern University sought an alternative to the usual cement mix required to make concrete. They settled on a technology that has been in development since the early 1970s: sulfur-based concrete.
The material is made by heating sulfur to around 240 degrees Celsius, mixing it with an aggregate and allowing it to cool - however, this process has occasionally proved problematic on earth, with the sulfur shrinking during cooling and causing cavities and internal stresses that weaken the final material. Lin Wan and his team, though, found that with an aggregate which emulates Martian soil (containing silicon dioxide, aluminium oxide, iron oxide and titanium dioxide) they were able to produce a concrete two-and-a-half times as strong as the minimum compressive strength required for building codes on earth.
They also found that the mixture, composed of 50% martian soil with a maximum aggregate size of 1 millimeter, would hold together in Mars' less dense atmosphere - circumventing problems that would be seen on the Moon, where the vacuum of space would cause the sulfur to sublimate into a gas and turn any freshly-built sulfur structure into nothing more than a pile of aggregate. "Both the atmospheric pressure and temperature range on Mars are adequate for hosting sulfur concrete structures," concluded Lin Wan.
Furthermore, reheating the sulfur again to 240 degrees would cause it to melt, meaning that the concrete is fully recyclable - therefore not only does Martian concrete eliminate the expense of transporting materials from Earth, but it also eliminates the expense of demolishing and discarding construction materials in a rapidly growing and changing Martian colony.
In October, NASA awarded $25,000 to Clouds AO and SEArch as the winners of their Mars Habitat Competition. Little did we know that they could be the first of a wave of new Mars-based practices, who are already being armed with the tools to make great architecture on a faraway world. Apparently, materials scientists are already waiting for us.
Story via MIT Technology Review