Out with the old

New equipment is providing a much-needed boost to research infrastructure in the transport and construction space. University of South Australia Professor Yan Zhuge explains.

Research is a fundamental aspect of the transport and construction sector.

The sector has universities to thank for seemingly everyday materials and methods, such as Recycled Asphalt Pavement, prefabrication and modular construction, digital twins, sustainable timber and more.

The University of South Australia’s newest addition, the Hopkinson bar, will help to greatly accelerate and validate such research. So, what is a ‘Hopkinson bar’ and what does it help to do?

The Hopkinson bar is a specialised scientific piece of equipment used to simulate and study dynamic loading conditions, particularly impact loading.

Primarily used in civil engineering to test how materials perform under sudden, high-speed forces, the Hopkinson bar has previously been used to simulate impacts from earthquakes, car crashes, bombings and other impact-related events.

The mechanical device was invented in 1914 by British electrical engineer Bertram Hopkinson, originally used to measure the pressures created by small explosions and projectile impacts. In 1949, Herbert Kolsky improved the technique by using two bars to measure the stress and strain that materials can withstand.

In the intervening years, the Hopkinson bar has been modified to allow for tensile, compression and torsion testing.

The existing bar is not advanced enough to test new materials that have different impact energies, hence the need for improvements.

University of South Australia Professor Yan Zhuge. Image: ASTE.

The current generation of Hopkinson bars in Australian universities also have accuracy issues and are time-consuming to use. That’s why the University of South Australia is developing a new version with improved technology to overcome these limitations.

This technology comprises a $720,000 new-generation biaxial Hopkinson bar that uses electromagnetics to apply pressure in two directions, investigating how well the materials stand up to a high-impact force.

The new bar will help researchers better understand how materials like concrete and infrastructure components respond to dynamic loading conditions, ultimately leading to more resilient and safer design of roads, bridges, tunnels, and other critical infrastructure.

The equipment is partly funded by a $420,000 ARC Linkage Infrastructure Equipment Facilities (LIEF) grant and supplemented with $300,000 cash from eight Australian universities. As University of South Australia Professor Yan Zhuge explains.

“Australia urgently needs more effective design methods to ensure its ageing buildings, bridges, and roads can withstand a projected increase in natural disasters by 2050 due to climate change,” she says. “It is essential that we create sturdy structures and systems to protect against a whole range of events, including human-made disasters. The existing testing methods for construction materials are not only time-consuming but often inaccurate.”

More resilient infrastructure not only provides benefits in terms of durability and performance, but it also helps to aid the overall sustainability of infrastructure development.

“If you have a resilient structure, that’s also sustainable, the structure can last 100 or 200 years, instead of designing it for 50 years,” she says. “That’s truly sustainable in its own way.”

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Similar to sustainable practices, the adoption of new technology has traditionally been a challenge in the sector, Zhuge explains. She hopes that once universities can validate their claims with research, stakeholders will show greater buy-in.

“I want to talk to all these civil and construction companies to encourage them to try to adopt new technology, because I think the people in this field are pretty traditional,” she says. “It’s very difficult for the Australian infrastructure and construction industries to adopt new technology. That’s our aim, to develop and investigate new technology and methods, in the hope of developing new, resilient and green infrastructure. After all, resilient structures are greener structures.”

On top of trialling the new Hopkinson bar, Zhuge and the rest of the University of South Australia team are looking into alternative materials and manufacturing processes that the market could adopt.

Just one of these is research into low-carbon materials, with the end goal being the development of concrete materials with reduced carbon emissions, by using waste materials to partially replace cement.

Zhuge says the key objectives of such research, in addition to reducing the carbon footprint of these materials, are maintaining high stress performance while preserving durability.

University of South Australia will also benefit from a $402,221 ARC Discovery Project grant, which has been awarded to Professor Zhuge. This funding will help investigate the viability of three-dimensional (3D) printing reinforced concrete.

3D printing is now common in digital construction, but it is currently restricted to printing concrete, not the reinforced material, so cannot be applied in a real-world setting. The project will also investigate a sustainable 3D printing alternative to Portland cement – an alkali-activated slag binder that hardens quickly and has significantly lower CO2 emissions.

“This is the first research project in the world to see if it’s possible to simultaneously print fibre-reinforced polymer along with concrete,” Zhuge says.

“We’re excited for the future in the transport space, especially with Artificial Intelligence and automation technology coming in. It’s research like that of UNISA’s doing that will lead to these significant changes.”

This article was originally published in the June edition of our magazine. To read the magazine, click here.