PAVING ROADS WITH TIRES

by Bennett Daviss
The rubber is hitting the road.
Engineers at Australia’s RMIT University have developed a paving material made from ground-up tires and crumbled building materials.
The project stems from concerns about the billions of old tires trashed annually and the mountains of useless rubble left over from constructing and demolishing buildings.
Building waste can be crushed and reprocessed to make a material called recycled concrete aggregate (RCA). This can be blended with other building materials for specialized uses such as drainage or filtering, or to reduce the amount of mined and quarried materials needed to pave roads.
The researchers found RCA works nicely as a roadbed for asphalt topcoats. But when the engineers added “crumb rubber” from granulated tires, the combination of 0.5 percent old tires and 99.5 percent RCA was stronger as well as more flexible, meaning it can last longer without cracking or breaking apart than conventional materials.
The blended material is the first of this kind of combination to meet road engineering safety standards.
TRENDPOST: Traditional roadbeds are made of rock and sand, costly to mine and impossible to replenish. The RMIT composite can replace those materials while also repurposing trash that otherwise might languish in landfills.
This new material takes us further along the way toward a circular economy, in which trash from one process is feedstock for another.
The recycled road material undergoes shear strength testing at RMIT.
Photo credit: RMIT University