Researchers at the Royal Melbourne Institute of Technology just invented a building material that could make construction projects stronger and more sustainable—and it’s based on the skeleton of an invertebrate that lives at the bottom of the ocean.
The material, recently presented in the journal Composite Structures, was developed by RMIT University engineers. It’s inspired by the skeleton of the deep-sea sponge, whose lattice-like internal structures, which have been optimized over millions of years in the ocean, allow it to thrive thousands of feet underwater.
The material’s unique structural properties make it simultaneously lightweight, strong, and extra resilient under pressure, meaning that it could eventually help make buildings sturdier with less steel and concrete.
How are steel and concrete damaging the environment?
For years, engineers have been researching new ways to cut down on steel and concrete in construction. That’s because both materials are produced at a massive scale, with equally massive impacts on the environment.
As of 2023, annual global production of concrete was around a whopping 30 billion tons, and the production of cement—one of concrete’s key ingredients—was responsible for between 5% and 10% of global CO2 emissions. Meanwhile, the steelmaking industry churns out about 2 billion tons of the metal per year, accounting for around 7% of greenhouse gas emissions.
Scientists have explored a wide range of alternatives to traditional steel and concrete, including a steel alternative made out of plastic and a form of concrete stabilized by recycled diapers.
Biomimicry as a basis for design
The RMIT team’s sponge-inspired material could help reduce steel and concrete use in construction because of something called “auxetic behavior.”
The word “auxetic” is a structural descriptor which means that, instead of becoming thinner when stretched and thicker when compressed, the material actually becomes thicker when stretched and thinner when compressed. A honeycomb, for example, is typically auxetic, as are biological materials like cat tongues and human muscle tendons. In the manufacturing world, auxetic materials are often used on the bottom of running shoes, allowing the footwear to expand while walking or running.
Auxetic patterns are desirable in construction because they can absorb force and maintain their strength under intense pressure, just like the deep-sea sponge. Existing man-made auxetic materials typically use a honeycomb pattern, but RMIT’s new material uses a double lattice design supported by diagonal beams. Based on the team’s testing, the innovative structure makes the material 13 times stiffer than other fabricated auxetics.
For this reason, the new pattern could be used in construction to enable “thinner load-bearing walls and slimmer columns without compromising structural integrity,” according to Jiaming Ma, the lead author on the new study. That would cut down on the amount of steel and concrete necessary to achieve a sturdy result.
The material is still in the testing phase, so it’s too early to predict what wide-scale commercial use might look like. Still, Ma believes it could eventually have applications across a wide range of industries, from creating earthquake-resistant buildings to improving vascular stents and strengthening protective sports gear.
