Soil grows not only fruits and vegetables, but also homes

 The soil in your backyard could be used to build a home, thanks to 3D printing technology.

Researchers from Texas and San Fransisco have come up with a way to turn soil into ink for 3D printing, according to a BBC report. By extracting clay from soil and mixing it with sodium silicate, the researchers created a material that could easily flow through a 3D printer, and harden shortly to form a strong, load-bearing structure.

 

Although 3D printed buildings are not new, the structures are often made of concrete, which accounts for 7-8 percent of global carbon dioxide emissions,according to some studies. Worse still, it’s currently not possible to reuse the building material.

“The environment impact of the construction industry is an issue of growing concern,’ said Sarbajit Banerjee, principle investigator on the clay-based 3D printing project.

Banerjee added:” Some researchers have turned to additive manufacturing, or building structure 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. “

In search of greener alternatives, scientists at Texas A&M University collected a soil sample in a colleague’s backyard. They extracted clay from the sample and mixed it with a non-toxic substance called carboxymethyl (trimethyl) ammonium chloride (CTAC),a by-product of the sugar beet processing industry, which “screens” the microscopic surface layer of the clay. This prevents the clay from absorbing water and expanding.

The scientists also added sodium silicate particles and cellulose fibers, which help the clay stick together so it can be more easily extruded through a 3D printer’s nozzle.

So far, the researchers have produced small-scale test structures made of processed clay. They want to improve the structures’ load-bearing capacity before trying something bigger.

Eventually, the team hopes to develop a “toolkit” that can be used to turn any type of soil into a usable ink for 3D-printing. Not only would this eliminate the need for cement, but it would also minimize the energy bills and greenhouse gas emissions associated with transporting heavy building materials long distances to construction sites.

Also of appeal is the opportunity for those in extreme or hostile environments to print large-scale structures, write 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.

The research, led by Professor Sarbajit Banerjee, will be presented this week at an online meeting of the American Chemical Society.

Source: tech.sina.com.cn; sciencefocus

Photo credit: sciencefocus.