If there’s one thing humanity is good at it’s making plastic really cheaply and using vast amounts of the stuff — so good, in fact that landfills are choked. But here’s an eco-friendly solution to a toxic problem: using waste plastic to pave roads.
Two projects, one in KwaZulu-Natal and the other in the Eastern Cape, are testing the use of melted plastic as the binding to pave roads. This dramatically reduces the need for bitumen, a by-product of the process of refining crude oil that is normally used as the binding agent.
In KwaZulu-Natal a road is being built at the Hammarsdale interchange on the N3, by local company Shisalanga Construction, a subsidiary of Raubex, an asphalt manufacturing and paving company.
Construction on the pilot project, which began on September 10, will use 200 tonnes of plastic sourced from local recyclers to pave the road.
A second plastic road, which began construction on August 5, is being built in the Eastern Cape municipality of Kouga. About 1.7km of Woltemade Street in Jeffreys Bay will be covered with plastic asphalt.
Gareth Nel of MacRebur, an international company leading this project, said the plastic roads are more flexible, meaning they can cope better with contraction and expansion caused by changes in the weather, reducing cracks and potholes.
“The road will work in South Africa’s climate because the product has been used in roads around the world such as the UK, Russia, Turkey, Canada, Australia, New Zealand and North America,” he said, adding that these countries have a wide range of different climates and that Australia and California have a similar climate to that of South Africa.
But don’t expect the plastic roads to look like a mash-up of Coca-Cola and Lipton ice tea bottles: the pundits say there is no difference in appearance. And whereas burning plastic releases harmful toxins, there is no toxicity produced by melting the plastic.
Marketing and communications executive from Plastics SA, Monya Vermaak, said that when “burning plastic in a high temperature in the presence of oxygen, all sorts of molecular interaction can take place and certain plastics may release toxins — carbon dioxide and methane being the most common”.
Nel said independent testing has been conducted to ensure that no micro plastics are released when the product is mixed with the asphalt.
Shisalanga’s financial manager, Lisa Mills, said: “The effects of plastic on the environment is devastating and companies cannot afford to continue ignoring the problem. Through this process there is the opportunity to utilise recycled plastic in a manner that will add value to the economy and society as a whole.”
She said since plastic is derived from petroleum it makes sense that it creates the same binding effect of bitumen with asphalt.
Mills said the percentage of bitumen that can be substituted with recycled plastic is dependent on the type of asphalt mix that is manufactured, which varies depending on factors such as traffic use and terrain on which the road is constructed.
Contractors canvassed by the Mail & Guardian said at this stage there is no cost advantage to using plastic.
South Africa is only just embarking on using plastic for paving roads, but India built its first plastic road 17 years ago. Pioneer Rajagopalan Vasudevan told The Guardian that the idea came to him when there was a call to ban plastic in India.
If the plastic were banned, it could severely affect the quality of life for a low-income family, he thought, but if you burn it or bury it, it’s bound to affect the environment.
So far, 16 000km of plastic roads have been paved in Tamil Nadu and the Indian government has granted approval for at least another 13 000km of roads across the country to be constructed using this material.
In his experiments, Vasudevan found that molten plastic was an excellent binder. The Guardian reported that when mixing plastic with bitumen he found that plastic stuck fast and bound the two materials together.
Mills said plastic roads are stronger than some asphalt roads and can be exposed to the same conditions as other asphalt blends. She said plastic roads can withstand temperatures as high as 70°C and as low as -22°C. “The product can also withstand high vehicle usage so would be considered good for use on highways with high traffic volumes,” Mills said.
Kouga municipality is governed by the Democratic Alliance. Its leader, Mmusi Maimane, visited the area on Monday. He said the party welcomes “new ideas and new technology that can open doors to investors, as well as deliver services to citizens”.
Maimane said if the road project is a success, it will open a window of opportunity in the region, which has an unemployment rate of 46%, with the potential for creating hundreds of jobs — not only in the construction of the roads, but also upstream in the collection and sorting of the waste.
The Council for Scientific and Industrial Research (CSIR) is working with the department of science and innovation to evaluate the feasibility of using waste plastic in local road construction.
The CSIR wants to identify waste plastics that are not currently attractive to the recycling sector, and evaluate their use for building plastic roads.
In a statement on Wednesday, the CSIR’s Georges Mturi, said the idea is to support industry and the government in finding new and local end-use markets for waste plastic. The CSIR “will ensure roads are built using quality materials that comply with proven performance criteria”.
Saied Solomons, chief executive of the Southern African Bitumen Association said: “Unless we are targeting the specific waste problem that we have in South Africa, there is no other need to use plastic material in our roads.”
He noted that it was not sensible to use plastic that was already being recycled for other purposes. “This is the general view of the asphalt road industry, which is also participating in this project,” Solomons said.
Tshegofatso Mathe is an Adamela Trust business reporter at the Mail & Guardian