Sustainability New flexible solution for old rubber tyres Flexiroc and Tyre Stewardship Australia join forces to ramp up Australia’s use of end-of-life tyres.
Blast testing at Australia’s only national blast simulation facility, at the University of Wollongong
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USTRALIAN entrepreneur Gary Bullock has come up with an ingenious way to make buildings fire and blast-proof. His invention, Protectiflex, is a concrete material that combines recycled rubber tyres and composite fibres in a cement matrix that can be sprayed onto buildings. Bullock, a structural engineer, established his company Flexiroc Australia in 2014, after he bought the rights to a rubber concrete made from recycled tyres. The company is recycling 10,000 tyres from Australia and another 500,000 tyres from around the world to include in blast-proof materials. Protectiflex has been tested at Australia’s national blast facility at the University of Wollongong and has so far delivered results beyond Bullock’s expectations.
38 APRIL 2020 Manufacturers’ Monthly
“In a normal explosion, that block work would disintegrate,” he explained. “What it does is it takes all the energy from the blast and it holds it all together. “So effectively, it’s enhancing the blast protection of that wall. If you have an existing wall, it means you can spray that wall and make it blast resistant.” Protectiflex can be used for a wide range of purposes where blast protection is needed, such as defence, heavy industry and in the petrochemical industry. It is also environmentally friendly, durable, light weight, and about 30 per cent lighter than concrete which can be used to make thinner lighter structures. “You can apply this material to either to an existing building or to a new building and do it as part of
the new building structure,” Bullock said. “Basically, it will enhance the blast resistance of that structure.” Testing panels from various building parts made up of concrete masonry blocks are coated with a thin layer of thin, which enhanced brittle block works. Professor Alex Remennikov from the University of Wollongong’s Faculty of Engineering said masonry walls form a common building component that are vulnerable to blast loads, created by terrorist attacks or accidental explosions. “The blast simulation facility was established to overcome the challenges associated with live explosive testing, such as very high cost, safety, efficiency and repeatability of test results,” he said. “We’ve used a blast simulator,
which is the only available facility in Australia and the southern hemisphere for blast testing of elements of buildings.” Protectiflex panels were tested at pressures 50 kilopascal and 100 kilopascals at the University of Wollongong, home to Australia’s only national blast simulation facility. “These panels have demonstrated exceptional performance because they didn’t develop any damage, cracks, and stayed intact,” Remennikov said. A coated masonry wall will endure far larger blast loads than a standard wall, Bullock said. “We’re getting very good protection of the masonry wall with smaller deflections and it’s totally intact,” he said. During test runs, sprayed Protectiflex walls were hit with shock loadings similar to a car bomb explosion from 20 metres away. In the past, Protectiflex walls have been used in either castin-place or precast construction methods. The spray on product provides another construction method to the technology making it more cost and time effective, especially when integrating with other construction materials. The spray-on application can be applied to both new and existing walls and buildings to develop or enhance their blast, ballistic and fire-resistance ratings. “We are confident these tests will prove the spray-on composite creates blast resistant walls,” he said. “The ProtectiFlex blast tests will demonstrate how spray-on retrofit could add strength and stiffness to concrete masonry walls, protecting occupants behind it from the blast loads. ProtectiFlex can be applied across a range of sectors including defence, government, critical manmonthly.com.au