Inspired by the tough outer layer of the human bone, engineers at Princeton University have developed concrete that is much more resistant to damage.
The research team led by Reza Moini, an assistant professor of civil and environmental engineering, and Shashank Gupta, a third-year Ph.D. candidate (pictured), has demonstrated that cement paste deployed with a tube-like architecture can significantly increase resistance to crack propagation and improve the ability to deform without sudden failure.
A/Professor Moini said the key to the improvement lies in the purposeful design of internal architecture, by balancing the stresses at the crack front with the overall mechanical response.
“We use theoretical principles of fracture mechanics and statistical mechanics to improve materials’ fundamental properties ‘by design’,” he explained.
The team was inspired by human cortical bone, the dense outer shell of human femurs that provides strength and resists fracture. Cortical bone consists of elliptical tubular components known as osteons, embedded weakly in an organic matrix. This unique architecture deflects cracks around osteons and this prevents abrupt failure and increases overall resistance to crack propagation.
The researchers’ design incorporates cylindrical and elliptical tubes within the cement paste that interact with propagating cracks. They expected the material to become less resistant to cracking when hollow tubes are incorporated, however, they learned that tube geometry, size, shape and orientation promoted crack-tube interaction to enhance one without sacrificing the other.
The team said there are more variables to investigate and more possibilities to explore. For further information search: Tough Cortical Bone-Inspired Tubular Architected Cement-Based Material with Disorder, published on September 10, 2024, in Advanced Materials.
About the author
Desi Corbett
Desi is the Editor of Concrete in Australia and at the helm of our magazine for 8 years. She was behind the Institute's weekly news bulletins from 2016-2021 and is now writing our focused news items. Desi has been an engineering news and features journalist/editor across all disciplines since 2013 - part of a 30-year career writing for a wide range of industries.