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Dr Alan Richardson, of Northumbria University. Credit: Northumbria University

Researchers are developing a new type of concrete that could significantly lower death tolls during bomb blasts, earthquakes and other disasters.

The international team— comprised of researchers from the U.K., India and Canada— are working to create a tougher form of concrete using 3D fiber reinforcement rather than the traditional 2D variety.

Initial trials have found that the new technique results in a concrete that is 78 percent more effective at holding together under shock waves and has far less fragmentation, meaning it would eject less material during a bomb blast, making it ultimately the safer option.

“The majority of injuries caused from bomb attacks are a result of fragmented building components energized by the blast wave, therefore it is vital to reduce fragmentation of concrete,” the study states. “It is known that fiber reinforcement can reduce fragmentation of concrete by increasing energy absorption.

“A three point beam test was conducted on two batches of beams reinforced with straight steel and 3D fibers respectively, so that flexural strength and post crack toughness could be calculated and compared.”

According to the study, 3D and straight steel fibers were embedded in cubes, so that pull out testing could be conducted and compared for the two fiber types. The 3D fibers showed higher flexural strength and post crack toughness, with a much higher pull out value.

After testing, the 3D fibers continued to span the rupture plane after initial crack formation during three-point bend testing, which held together the concrete matrix.

The additional strength also make it ideal for structures including sea defenses, motorway barriers, bridges and buildings located within earthquake zones. 

“We have seen that during terrorist attacks such as the Madrid bombings in 2004, many of the injuries that occurred were due to flying concrete shrapnel,” Alan Richardson, PhD., an associate professor of Civil Engineering at Northumbria University and Chairman of the Northern Region of the Concrete Society, said in a statement. “This is because the 2D steel fibers currently used in concrete production are randomly spread throughout the mix and may not be particularly effective at holding together the concrete in the event of an explosion.

“This has huge potential for a wide variety of applications. What we hope to do now is work with industry to develop this further,” he added.

After the 3D steel fibers are produced in India, the concrete is then mixed and tested with a loading frame at Northumbria.

The study was published in Science Direct.

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