Portuguese 
English 
Spanish 
4 min of reading 
1 comment 
Princeton Engineers Create Cement for Construction, 17 Times Stronger and 19 Times More Flexible. Learn How This Technology Revolutionizes Civil Engineering
Princeton engineers, inspired by the material of oyster shells, have created a new cement compound for construction that is 17 times more crack-resistant and 19 times more capable of stretching and deforming without breaking compared to standard cement. These findings could enhance the crack resistance of a wide range of fragile ceramic materials, from cement to porcelain.
Innovation in Construction
If we can design concrete to resist crack propagation, we can make it stronger, safer, and more durable.
Shashank Gupta, Graduate Student in Reza Moini’s Lab in the Department of Civil and Environmental Engineering.
ARTICLE CONTINUES BELOWSee also
Chinese engineers begin filling a 217-meter dam at an altitude of 3,000 meters and prepare a 2,240 MW hydroelectric power plant to integrate hydropower, solar, and wind energy in the upper Jinsha.
São Paulo surprises the world and aims to become a reference in public transportation: the plan includes 200 km of new tracks, up to 14 lines, and simultaneous operation of 8 tunnel boring machines in mega projects by 2040 in the metropolitan area.
Fernando de Noronha will receive affordable houses made with lightweight concrete technology that facilitates transportation to the island; the investment is R$ 12.9 million and families must have an income of up to R$ 2,850.
New “clean concrete” uses shrimp shell waste to reinforce geopolymer, increasing strength by up to 67% and creating antibacterial material for panels, tiles, and coatings in sustainable construction.
In an article published on June 10 in the journal Advanced Functional Materials, the research team led by Moini, an assistant professor of civil and environmental engineering, reported that creating alternating layers of tabulated cement paste and fine polymer can significantly increase crack resistance and the ability to deform without completely breaking (ductility).
Biological Inspiration in Construction
Moini’s lab often seeks inspiration from biology for their work in building materials. In this case, the team developed a compound inspired by a natural material known as nacre, or mother-of-pearl, which is found within certain shells. At the microscopic level, nacre consists of hexagonal tablets of the hard mineral aragonite bonded by a soft biopolymer.
The aragonite tablets significantly contribute to the strength of nacre, while the biopolymer adds flexibility and crack resistance. The hardening mechanism implies that the aragonite tablets slide under stress, which, along with other mechanisms, allows nacre to dissipate energy. This sliding action, combined with crack deflection and biopolymer deformation, allows nacre to withstand substantial mechanical stress while maintaining its structural integrity, making it strong and resilient.
Development of the Innovative Compound in Construction
The Princeton team developed innovative compounds inspired by nacre, using conventional building materials like Portland cement paste combined with a limited amount of polymer. They alternated layers of cement paste sheets with a highly stretchable polymer, polydimethylsiloxane. The researchers created small beams of multiple layers by alternating sheets of cement paste with thin layers of polymer. These beams were subjected to a three-point bending test with a notch to assess crack resistance (or fracture toughness).
Experimentation and Results
In the experiment, the researchers produced three types of beams. The first type consisted of alternating layers of cement paste sheets and fine polymer. For the second type, they used a laser to engrave hexagonal grooves into the cement paste sheets. These grooved sheets were stacked with thin layers of polymer between them. The third type was similar to the second, but the researchers completely cut out the cement, creating separate hexagonal tablets connected by the polymer layer. These cement paste tablets were placed on top of the polymer layer in a way similar to how aragonite is positioned over the biopolymer layer in nacre. All three types were compared to a solid reference of monolithic cement paste.
The experiments revealed that the failure of the reference beams was brittle, meaning the beams broke suddenly and completely upon reaching their failure point, without ductility. The beams with alternating layers, both grooved and un-grooved, exhibited greater ductility and crack resistance.
Future Applications
The most significant results were observed in the beams with completely separate hexagonal tablets, similar to nacre. These beams exhibited 19 times the ductility and 17 times the fracture toughness while maintaining nearly the same strength as the solid cement paste beam.Construction
Our bioinspired approach is not simply to imitate nature’s microstructure, but to learn from the underlying principles and use them to inform the engineering of man-made materials. One of the key mechanisms that makes a piece of nacre resistant is the sliding of the tablets at the nanoscale. Here, we focused on the tablet sliding mechanism by designing the incorporated tabulated structure of the cement paste in balance with the properties of the polymer and the interface between them. In other words, we intentionally designed defects in brittle materials as a way to make them stronger by design.Construction
Reza Moini
The researchers noted that the findings are based on laboratory conditions and additional work and research would be needed to develop the techniques for field use. They are working to determine if the fracture toughness and ductility of the structures apply to other ceramic materials besides cement paste, such as concrete.Construction
We are just scratching the surface; there will be countless design possibilities to explore and design the constitutive properties of hard and soft materials, the interfaces and the geometric aspects that influence the fundamental size effects in building materials.
Reza Moini
More information: princeton.edu
Bom dia! Excelente e abençoada descoberta, vamos torcer para que chegue no mercado o mais rápido possível.