This concrete is significantly more robust and break-resistant due to its special design and manufacturing process. It resists cracks up to 63 percent better than conventional cast concrete.
This is made possible by a newly developed combination of geometrically precise 3D printing in large industrial robots and chemical additives that accelerate the hardening of the concrete. By mixing these additives into the concrete immediately in the spray nozzle during printing, the material can be molded into the desired shape without deforming under its own weight.
The researchers led by Arjun Prihar from Princeton University were inspired by nature when it came to the structure of the new type of concrete: it resembles the double helix structure of the collagen fibers in the break-resistant scales of an ancient species of fish called the coelacanth. The chitin shell of some crabs also has a similar structure. To imitate this, each concrete strand is first printed into shape so that it is loosely connected to its parallel neighboring strand. Twisted in a helical shape and stacked on top of each other, the individual layers then form any shape, such as beams or columns.
This geometric structure stops or redirects cracks in the concrete at the transitions and the fracture surfaces become angled, making it harder for cracks to spread. The technology is therefore a kind of natural reinforcement mechanism for concrete.