Scientists reveal 3D-printed concrete that actually gets stronger when it cracks

4 Oct 2018663 Views

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Researchers aiming to make buildings much safer during natural disasters have revealed 3D-printed concrete that gets stronger when cracked.

As the old saying goes, ‘what doesn’t kill you makes you stronger’, and when it comes to the latest concrete design, that couldn’t be closer to the truth.

In a paper published to the journal Advanced Materials, a team from Purdue University in the US revealed an advanced 3D-printed concrete paste designed to actually become stronger when it starts to crack.

The new material drew inspiration from nature, specifically the shell of arthropods such as lobsters and beetles that get tougher under pressure. In doing so, the creators hope that the concrete paste could be used to make houses and buildings stronger during wildfires and earthquakes.

With a ‘built-in’ weakness, the concrete would be able to control how damage spreads between the printed layers of the material, similar to trying to break a bundle of uncooked spaghetti versus a single piece.

Power of the ‘dactyl club’

The Purdue team is the first to harness 3D printing to create bioinspired structures using cement paste, potentially giving future engineers greater control over design and performance at a scale not achievable before.

“3D printing has removed the need for creating a mould for each type of design, so that we can achieve these unique properties of cement-based materials that were not possible before,” said researcher Jeffrey Youngblood.

The team also analysed the material using micro-CT scans to see how 3D-printed, cement-based materials behave, with their major advantage being the ability to control how they crack under pressure.

The original inspiration for the design was the mantis shrimp, famous for its ‘dactyl club’ appendage that grows tougher on impact through twisting cracks that dissipate energy and prevent the club from falling apart.

So far, using this method, the team has used the paste for a number of 3D-printed techniques, including a honeycomb design and ‘Bouligand’. This latter example takes advantage of weak interfaces to make a material more crack-resistant.

Colm Gorey is a journalist with Siliconrepublic.com

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