Pouring concrete is part science, part art. The mix has to be given time to cure at a proper temperature and humidity; if it isn’t cured properly, the concrete can be prone to cracking.
Improper curing can lead to delays in builds being completed and can even make structures prone to damage and collapsing.
Enter the concrete-printing robot. Mechanical arms swing back and forth, programmed not to collide, mixing and pouring concrete into large-scale structures. The robot’s optimisation means that the mix is blended evenly to ensure consistency and for a faster curing time, speeding up the strengthening process.
In 2018, a team of researchers at Nanyang Technological University (NTU) in Singapore, led by Pham Quang Cuong, an associate professor at the School of Mechanical and Aerospace Engineering, achieved just this.
Using two robotic arms, the NTU researchers were able to print a concrete structure measuring 1.86m by 0.46m by 0.13m in just eight minutes. The structure took two days to harden and a full week to reach its full strength – in standard industrial cases, concrete can take up to 28 days to achieve its maximum strength, although this isn’t a hard-and-fast rule.
According to Pham, the ability to use 3D-printing dexterous robots could give architecture and construction companies the option to pour more complex designs.
The NTU team haven’t been the only people innovating in this area – Netherlands-based CyBe and Swiss firm Sika are specialists in 3D concrete printing. But the NTU’s invention is smaller and lighter, which would make it easier to transport if the technology were ever to be scaled up.
“We imagine it could be used in a situation where the robots are transported to a construction site, deployed to print the concrete structure that is needed and then they’re transported onto the next site,” said Pham, who is also the founder of an NTU spin-out, Eureka Robotics.
The construction industry is notoriously slow when it comes to embracing and implementing innovations. The reason being, said Andreas Velling, a mechanical engineer at sheet-metal fabrication company Fractory, is that construction sites are full of people, moving objects and heavy machinery, which makes testing technology tricky.
“Any new technology usually requires a controlled environment. A construction site is pretty much as far from this definition as you can go,” added Velling.
The industry has also long been seen as one of the slowest to adopt digitisation, preferring instead to rely on paper-based processes and work off paper-based blueprints.
One study, by KPMG, found that two-thirds of 200-plus construction and…