Princeton engineers develop bone-inspired cement that’s 5.6 times more resilient

Inspired by the structure of human bones, a team of Princeton engineers has developed a cement-based material with 5.6 times the damage resistance of traditional materials

A team from Princeton, using the structure of human bones, developed a new cement-based material that proved to have resistance to damage 5.6 times higher than conventional alternatives. This work addresses one of the large problems encountered with cement-brittleness. This new material, having a bio-inspired design, shows resistance to crack formation; hence, it does not fail catastrophically like conventional cements.

In a research conducted by Professor Reza Moini, along with PhD student Shashank Gupta, and published in Advanced Materials, it was shown that a tubular-based architecture can substantially enhance the crack resistance of cement by letting this most-used material in human history deform under tensile loading without any sudden fracture.

One of the major problems in the engineering of brittle materials is the possibility of their catastrophic failure.

In nature, human bones exhibit the best example of resistance and flexibility in coordination. The cortical tissue with an elliptical structure is able to deflect cracks and retard crack propagation. The idea here was human femur bones, comprising the osteon structure, as the reference model for developing a cement paste that included an internal arrangement of cylindrical and elliptical tubes.

Stronger material thanks to tubular geometry

The big challenge for the engineers was how to introduce hollow tubes into the material without weakening it. Astonishingly, the geometric arrangement and just the right decisions about the size, shape, and orientation of the tubes granted superior strength. This approach triggers a stepped reinforcement mechanism where cracks get trapped by the tubes and delayed, dissolving energy at each interaction. This mechanism prevents the material from sudden failure, turning it much more durable.

Probably the most significant innovation coming out of this study was how the team toughened cement, sans additions of fibers and plastics, but instead forced changes upon the internal structure of the material, thereby achieving remarkable improvements from design alone. They also introduced a new method for quantifying the degree of disorder within the tube arrangement-highly important when optimizing material strength.

We are just starting to scratch the surface of what is possible. The same principles could be applied to other types of fragile materials to make them more resistant to damage.

Beyond these mechanical gains, the Princeton team also develops more sophisticated robotic fabrication and 3D printing methodologies toward the creation of even more complex and resilient materials. According to Moini, this process has very good prospects for scaling the large-scale application of the bio-inspired cement-for example, in civil infrastructure.

Source: Princeton University