A fracture-resistant cement could make mile-high skyscrapers possible

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Imagine a fracture-resistant material that could be used to create a building 10 times as high as the world’s current tallest building, without being destroyed under its own weight. That is something that researchers from the University of Konstanz in Germany have been working on. They have developed a new type of cement with impressive anti-cracking properties that is capable of resisting the kind of fractures found in regular cement. Not only could it be used for constructing incredibly tall buildings, but also more earthquake-proof structures, and new thinner building developments that nonetheless retain an impressively high level of strength.

Oh, and did we mention that it is inspired by small spiny creatures which live underwater?

“We have changed the nanostructure of cement and made it more ordered by taking inspiration from the sea urchin spine structure,” Professor Helmut Cölfen told Digital Trends. “The main novelty of our work is that the fracture resistance of calcium silicate hydrate (CSH) — the binder in cement and concrete — was significantly improved by the first reported ordered CSH nanostructure. The problem of CSH is that, although it shows good compressive strength, it presents a lack of elasticity and has a poor flexural strength. This problem is now overcome with our elastic [material].”

fracture resistant cement sketch mesocrystal formation

While next-generation cement and sea urchins spines aren’t a natural pairing, Cölfen explained that both operate on the same principle. Sea urchin spines are mostly made of a delicate brittle crystalline material called calcite. However, the spines are more durable than the raw material because of the brick wall-style architecture they employ. By synthesizing cement to resemble this structure at a nano level, the researchers were able to develop a material that is immune to cracking in the way that regular cement does.

It might not be used exactly in its current form, though. “Our work shows what is possible in principle if ordering of the nanoplatelets and interspacing with a soft material can be achieved,” Cölfen continued. “But our study does not yet have an application since the dimensions of our mesocrystals are small, and the polymer mortar would likely be too expensive to be used on a large scale. But it would be easy to simply mix the mesocrystals as an additive for improving cement as potential crack stoppers.”

In tests, the team found that the cement can be used to create concrete between 40 to 100 times stronger than current mixes.

A paper describing the work was recently published in the journal Materials Science.