Producing something useful out of waste materials that would otherwise be discarded is the ideal scenario when it comes to sustainable recycling. One place where we could put old tyres? Literally on the surface of the road.
Using a blend of old tyres and rubble left over from construction projects, a newly developed material has been found to be able to take the pressures of traffic. It’s actually more flexible than standard road materials, and thus less likely to crack.
The mix of recycled concrete aggregate (RCA) and tyre crumbs is suitable for use as a base layer, beneath the asphalt laid on top. RCA is already used in this way, but the addition of pieces of tyre makes it even better able to cope with the elements.
“Traditional road bases are made of unsustainable virgin materials – quarried rock and natural sand,” says civil engineer Mohammad Saberian Boroujeni from RMIT University in Australia.
“Our blended material is a 100 percent recycled alternative that offers a new way to reuse tyre and building waste, while performing strongly on key criteria like flexibility, strength, and permanent deformation.”
Machines specifically designed to simulate the strains of a lifetime of passing vehicles were used to test different mixes of RCA, coarse tyre crumbs, and fine tyre crumbs.