Robotics and additive manufacturing produce tougher concrete

This is the claim of researchers at Princeton Engineering whose designs are said to have increased resistance to cracking by as much as 63 per cent compared to conventional cast concrete. The team’s work is described in Nature Communications.

The researchers were inspired by the double-helical structures that make up the scales of an ancient fish lineage called coelacanths. Research lead Reza Moini, an assistant professor of civil and environmental engineering at Princeton, said nature often uses ‘clever architecture’ to increase material properties such as strength and fracture resistance.

To generate these mechanical properties, the researchers proposed a design that arranges concrete into individual strands in three dimensions.

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The design uses robotic additive manufacturing to weakly connect each strand to its neighbour. The researchers used different design schemes to combine many stacks of strands into larger functional shapes, such as beams.

The design schemes rely on slightly changing the orientation of each stack to create a double-helical arrangement (two orthogonal layers twisted across the height) in the beams that is key to improving the material’s resistance to crack propagation.