Walls built from used tyres packed with earth are as structurally sound as conventional walls used in residential buildings, according to a new study by the University of South Australia (UniSA).
The waste from used tyres is a major sustainability challenge globally, with Australia alone generating an average of 55 million end-of-life tyres (450,000 tonnes) each year.
Tyre walls, packed with rammed earth or other materials, have been used for decades in alternative buildings, including retaining walls and earth-sheltered homes.
However, a lack of strong empirical data has limited their wider adoption by architects and engineers. There are also currently no certified design guidelines or code provisions available for tyre wall systems.
With support from Tyre Stewardship Australia, a research team from UniSA assessed the structural integrity of a test tyre wall, and examined how the structure performed under various stressors.
The researchers built a load-bearing test structure by laying the earth-filled tyres in a staggered manner similar to masonry walls. They then tested its strength by applying both top-down loads (to simulate a roof) and horizontal force.
UniSA industrial design lecturer Dr Martin Freney said the research showed the material offers benefits over some traditional building approaches, particularly for retaining walls.
“Not only are the tyre walls as structurally sound as concrete or wood sleeper retaining walls, they are also extremely resilient,” Dr Freney said.
“Unlike a concrete wall, we found these walls have the ability to ‘bounce back into shape’ following impact, such as from an earthquake.”
An added benefit is the walls can also offer excellent drainage if a material such as recycled concrete rubble or crushed bricks is used to fill the tyres, Dr Freney said. This can be advantageous in retaining walls.
“The wall we tested was the first of its kind to be scientifically tested in this fashion, and all the data indicates tyre walls can be extremely strong and safe structures,” Dr Freney says.
“We’re hoping this study will change that and expand the range of projects in which these walls are used.”
Alongside Dr Freney the UniSA team consisted of Yachong Xu, Reza Hassanli, Yan Zhuge, Mizanur Rahman and Rajibul Karim
In the next phase of the research Dr Freney will engage with industry to develop a range of real-world applications for tyre walls.