Last month brought news that an experiment to investigate how cement sets in low-gravity environments was included in the latest resupply mission to the International Space Station. Designed by researchers at Penn State University, led by Dr Aleksandra Radlinska, the Microgravity Investigation of Cement Solidification (MICS) experiment aims to understand how the microstructure development of cement during hydration and hardening will differ in microgravity compared to the conditions found on Earth.
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As the NASA website puts it: “minimising gravity-driven phenomena, such as thermosolutal convective flow and sedimentation, ensures crystal growth strictly by diffusion, and considerably different microstructure than that observed in typical laboratory conditions on Earth.”
Now that may sound relatively abstract (why do we need to know how cement hardens in space?) but the research could have some interesting applications. Staying in space, the MICS investigations “directly addresses the high priority need for lightweight space structures for habitats that protect crew”.
As AFP reported it: “In order for human explorers to set up camp on Mars, they will need to build habitats to live in and places to protect their gear.” Cement would be an obvious choice for such structures – but only if hardens with the same strength as it does here on Earth. MICS aims to answer that question.
It also begs other questions: could the cement be manufactured on Mars (or other extraterrestrial environments) or would it have to be transported from Earth? Which of the cement producers will be first to make the (giant) leap into space? Will we have to rename World Cement, Intergalactic Cement?
OK – so I may be being slightly facetious with those. There may come a time when cement structures in space are required; when that happens, it will be important to know ahead of time whether such structures are possible. In the meantime, the researchers also note a number of more mundane applications of the experiment. .
According to the description on the NASA website, “MICS can increase understanding and control of the crystal growth kinetics and morphology, to improve cement properties. Improved cement properties can lead to improved concrete properties, durability, and lower CO2 emissions.”
MICS thus taps into two major current ideas within the cement and concrete industries: how to make cement greener and how to make concrete last longer. .
“We have so many reinforced concrete structures and are continuing to build them,” Randolph Langenbach, a Building Conservation Consultant, told a recent CNN article entitled “Can the Building Industry Break its Addiction to Concrete?” “These buildings are all likely to have to be replaced or undergo significant structuring repairs to their reinforced concrete frames within 50 – 150 years. Your eyes grow wide when you think of the scale.” .
Greater concrete durability should therefore be a key part of addressing the sustainability challenge facing the construction industry. The experiment aboard the International Space Station may sound like something from a Star Trek movie, but maybe a dose of extraterrestrial science (the ultimate blue-sky thinking) is needed to solve some of Earth’s most intractable problems. I am certainly looking forward to the results.