Two-pronged approach to strengthen concrete

RESEARCHERS at Princeton University in New Jersey, US, are making significant strides in developing tougher concrete through two distinct, but complementary, approaches - a bio-inspired tubular design and double-helical design with robotics.

These two research projects offer promising avenues for developing next-generation construction materials with superior resistance to cracking and damage.

BIO-INSPIRED DESIGN

Inspired by the architecture of the human bone's tough outer layer, engineers at the private Ivy League research university in Princeton have developed a cement-based material that is 5.6 times more damageresistant than standard counterparts. The bio-inspired design allows the material to resist cracking and avoid sudden failure, unlike conventional, brittle cement-based counterparts.

In a September 10 article in the journal Advanced Materials, the research team led by Reza Moini, an assistant professor of civil and environmental engineering, and Shashank Gupta, a third-year PhD candidate, demonstrate 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.

"One of the challenges in engineering brittle construction materials is that they fail in an abrupt, catastrophic fashion," Gupta said.

In brittle construction materials used in building and civil infrastructure, strength ensures ability to sustain loads, while toughness supports resistance to cracking and spread of damage in the structure. The proposed technique tackles those problems by creating a material that is tougher than conventional counterparts while maintaining strength.

Moini said the key to the improvement lies in the purposeful design of the 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 the materials' fundamental properties 'by design'," he said.