ECO HOUSES
Clay used in 3D printers could replace concrete
Your next home could be made of mud! By extracting the clay component from soil and mixing it with sodium silicate, researchers from Texas and San Francisco were able to produce a material that could flow easily through a 3D printer, but hardens quickly to form a strong, load-bearing structure.
The composition of a soil sample can vary greatly, containing any mixture of clay, rock and organic material. So, the researchers aimed to develop a tool that would turn any type of soil into a useable ‘ink’ for 3D printing.
They say that after a quick analysis of the soil, their toolkit could figure out how much sodium silicate was needed to be added to the sample, in order to turn it into a printable building material.
The ability to 3D print buildings has been around for a few years, with large robots using concrete to create frameworks for houses. However, many are concerned with the environmental impact of relying on concrete – it’s estimated that 7 per cent of global carbon dioxide emissions come from the cement industry, and it’s not currently possible to recycle the building material.
“The environmental impact of the construction industry is an issue of growing concern,” said Sarbajit Banerjee, principal investigator on the clay-based 3D printing project. “Some researchers have turned to additive manufacturing, or building structures
“The materials used in 3D printing need to be sustainable”
layer by layer, which is often done with a 3D printer. That advance has begun to transform this sector in terms of reducing waste, but the materials used in the process need to be sustainable as well,” he cautioned.
The team say that using a local soil source can cut transport emissions while helping the surrounding community. The technology is also of interest for those in extreme or hostile environments to robotically print largescale structures, say the researchers in their paper, such as building clinics in times of war or in disease-ridden jungles, or even in extra-terrestrial planetary environments such as Mars.