One of the most straightforward, easiest to access, and cheapest route to recycling tyres is to use them as they come off the vehicle.

Whole tyres that need no prep and no processing offer an ideal material if only there were a use for them. Of course, there has long been a use for whole tyres. They can be used to build retaining walls rammed with earth. In embankments, they can also be planted to create a green wall of reinforcement to prevent landslips.

However, with a little thought, they can be used as construction materials to create buildings, sometimes known as Earthships.

Now, a new study by The University of South Australia has tested and verified the structural integrity of walls constructed from tyres packed with earth, with the results potentially providing new opportunities for the reuse of end-of-life tyres in the construction industry.

According to the University’s Dr Martin Freney, a wall created using tyres and rammed earth proved to be as structurally sound as conventional walls used in residential applications.

“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.

“While that structural integrity has been observed for many years in applications such as the retaining walls in earth-sheltered, Earthship homes, the lack of supporting data has prevented wider uptake of tyre walls by engineers and architects, and we are hoping this study will change that and expand the range of projects in which these walls are used.”

In considering expanded uses for tyre walls, Dr Freney suggests several unique characteristics of the structures may offer 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, but they are also extremely resilient.

“Unlike a concrete wall, we found these walls have the ability to ‘bounce back into shape’ following impact, such as from an earthquake.”

“And if a drainage material such as recycled concrete rubble or crushed bricks is used to fill the tyres, they also offer excellent drainage, which can be a major consideration in many retaining wall scenarios. Furthermore, using recycled fill materials reduces the wall’s environmental impact.”