How lobster shells are teaching scientists to make stronger concrete

Jonathan Tran spends a lot of time thinking about lobster. Not steamed with butter, or with mayo on a toasted rollthe Australian engineer is using the design of the lobster's shell to make concrete stronger.

Researchers have marvelled at the lobster's ability to withstand the pressure of tonnes of water pressing on it as it lives on the sea floor.It does not get crushed by the weight.And if you've ever opened one, you know how tough those shells are to crack.

"The secret is, if you look into the microscope, [the shell] is not a single layer," Tran, a professor at the Royal Melbourne Institute of Technology, said in an interview with CBC's Island Morning.

"It's actually ...multiple, hundreds of layers that stuck together."

The layers are also not oriented in the same direction, but twisted around.

Researchers wanted to mimic that pattern but could not find a way to do it until larger 3D printers were constructed, Tran said.

Some of these very large printers are now able to construct homes in about 24 hours.

The robot arm can move in a programmable way so that it can be controlled by a computer, said Tran.

That lets operators attach a nozzle with a concrete pump. "The combination of the concrete pump and the robot arm allow it to control the direction where we print the material layer by layer."

The result is concrete that is stronger and can be used in complex building projects where arches or intricate shapes are needed.

Tiny steel strands can bemixed with the concrete to make it able to withstand extreme weather and temperatures something that has caught the attention of NASA.

Eventually, Tran said, they might be able to build "resilient structureson the moon or Mars in the future, because it is a very harsh environment. But we have to develop the way that we print."

Tran said the new method eliminates the need for moulds, instead precisely placing multiple layers of concrete from the printer into place.

He says the team will now focus on how to make the concrete strong enough that it won't need any extra support while it cures.

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