The bitumen which is usually used for South Africa’s tarred roads is strengthened with expensive imported polymers, says Georges Mturi, manager of CSIR’s Advanced Material Testing Laboratories,, but the “rubber road” uses locally available additives.
He added that the experimental road, which is frequently used by heavy vehicles, hadn’t sustained any damage or deformation in its year of use.
“Any recycled product is a more sustainable solution because you are creating a new end market to reduce waste material, and it’s economical given it’s a waste material,” Georges says.
“The major benefit of this invention will be an increase in the recycling of waste tyres in the road industry, for the benefit of building better-performing roads.”
As is often the case with breakthrough inventions, the road project was motivated by a shortage of bitumen (a petroleum byproduct also known as asphalt) from refineries, which meant that it had to be imported at great expense.
It’s a joint project between the CSIR and Much Asphalt Gauteng Regional Laboratory.
The road was made from two asphalt layers. The bottom layer is a 60mm layer of bitumen and the top 40mm-thick layer, on which vehicles drive, is made from bitumen modified with recycled tyres and specialist polymers.
It’s not the first road that’s been constructed using recycled tyres, but it uses more recycled materials than previous efforts.
“The technology applied in this research was aimed at the further recycling of waste coming from the bitumen-rubber binder for other roads once it’s no longer usable. We’re re-recycling the binder that already contains up to 20% of recycled tyre material.”
Not only is this new type of road economical, it’s also environmentally friendly, Georges says.
“We need to create new sustainable markets to inspire new industries to create employment, construct better-performing roads as well as reduce the global challenge of accumulating waste streams.”
RECYLED ROADS Last year, the first-ever South African road to be made with plastic containing asphalt was paved in KwaZulu-Natal. The 80m road in Cliffdale was constructed to tackle two serious issues – too much plastic waste and damaged roads. It was made from locally recycled plastic, which makes it an affordable option. Other countries such as the US have used this method before, but it was the first of its kind in SA.
Jeffreys Bay in the Eastern Cape also has its own stretch of road made from recycled plastic asphalt. Constructed in 2009, the 300m stretch is said to have saved costs of up to R5.5 million compared to a normal tar road of the same distance.
The world’s first road made from recycled plastic was constructed in the Netherlands in 2018. The 30m bike path was manufactured in a factory and didn’t contain any asphalt. It was carried to the site and assembled at the location.
While the road is made almost entirely from recycled plastic, it’s expected to last three times longer than conventional asphalt roads, according to ecoist.life.
SOURCES: heraldlive.co.za; shisalanga.com, ecoist.life