When the rubber hits the road

The TopCoat asphalt team achieved a ‘first’ for Adelaide when they successfully paved warm mix dense graded asphalt in the leafy suburbs of Mitcham Council last week. This is a big step forward in improving the performance of asphalt and helping reduce the disposal of old tyres to landfill. Approximately 1.5 end of life tyres was used in every tonne of asphalt paved. 10% RAP was also used in the manufacture of the asphalt to improve its performance. The asphalt was manufactured at 160 degrees and paved at a temperature around 140 degrees without any workability or fuming issues.

By producing asphalt at lower temperatures from rubber recovered from used tyres and reclaimed asphalt TopCoat where able to improve the sustainability of the asphalt by:

• Reducing the amount on non-renewable raw materials required i.e. bitumen, aggregates and polymers in the asphalt
• Reducing the amount of energy required versus using virgin materials
• Providing an asphalt which is more durable and requires less maintenance because it is less oxidised, is more flexible and less prone to cracking or rutting.

Reusing rubber from old tyres in asphalt has a proven track record of rendering improved performance of up to 50% against conventional asphalt. For this reason, the State of California have legislated that 30% of their asphalt must be modified with rubber from used tyres. Not only does this reduce road maintenance costs but also helps keep used tyres out of landfills.