Hyderabad: What once was an environmental menace could be a practical infrastructure solution as India leads the mission of transforming plastic waste into plastic roads. Instead of piling up in landfills, floating in oceans, cluttering city streets, littering beaches, and filling up gutters, waste plastic is now being repurposed for road construction, emerging as a promising remedy to the pressing ecological hazard.
Since 2016, India has seen increasing support and involvement from both state and local governments, resulting in the construction of thousands of kilometres of roads with waste plastic-infused bitumen mix. The central government has asked all states and UTs to use plastic waste up to 8 per cent of the weight of bitumen in roads within cities, including internal roads of housing colonies and office complexes.
Such roads aren’t just proving effective against plastic waste but have also been found to feature additional benefits, including lower construction costs, increased load-bearing capacity and durability, and lower environmental impact.
Where it all began
Rajagopalan Vasudevan, a professor at Thiagarajar College of Engineering in Tamil Nadu, introduced the idea of combining plastic waste with road construction materials. This method created a durable, eco-friendly alternative to traditional roads. Vasudevan patented the technology in 2006, and it gained widespread adoption across India in 2015, thanks to government support.
Chennai took the first step in 2004, constructing 1,000 kilometres of plastic roads, demonstrating the technology’s potential. Since then all major municipalities in India have experimented with the technology including Pune, Mumbai, Surat, Indore, Delhi, Lucknow, and more.
Across the nation, nearly 40,000 kilometres of rural roads have been constructed under the PMGSY programme. According to the Ministry of Road Transport and Highways, as of February 2024, about 2,900 km of National Highways have been constructed using waste plastic, marking an exponential rise over a 703 km stretch in July 2021 and over a 1700 km stretch in December 2022.
Vasudevan’s work earned him the Padma Shri award in 2018, recognising his valuable contribution to waste management and road construction.
Talking to ETV Bharat's Sivakumar, Vasudevan applauded the government’s initiatives and directives related to the adoption of plastic roads. “This is a great leap for a small work done at the Thiagarajar College of Engineering, Madurai. Now, more than 3 lakh kilometres of roads in India have been converted into plastic tar roads, including the roads at the border.”
Vasudevan also highlighted the plastic road technology being adopted overseas. “We have extended our technology to Malaysia and Indonesia via an MoU. We also have MoUs with many South African countries, including Congo,” he said.
The idea of plastic roads
Even though plastic roads are providing a more durable form of traditional roads, the primary reason for their adoption continues to be the eradication of plastic waste. Talking to ETV Bharat, Professor Vasudevan reflected on how the problem of plastic waste gave birth to plastic road technology.
“Around the year 2000, there was a move to ban plastic by the Tamil Nadu government. This created fear in the minds of plastic manufacturers. There were more than 7,000 manufacturers in the state alone, with more than 1 lakh people working in the industry. They feared for their jobs and livelihoods,” Vasudevan said. “If plastic was banned, what would happen to them? This was in the minds of many people, including myself.”
Thinking about the problem, an idea struck Vasudevan, making him see plastic as a by-product of petroleum, which also produces petrol, diesel, kerosene, tar, and plastic materials. He noticed that plastics such as polyethylene, polypropylene, and polystyrene all belong to the petroleum family. “Therefore, as a chemist, I thought that plastics should be soluble in bitumen, otherwise called tar. If it is soluble, we can use plastic-modified bitumen for roads,” he said.
“I tested this idea in the laboratory and was able to dissolve plastic in bitumen to the tune of 3 to 4 per cent. After testing the quality of the polymer-modified bitumen, we concluded that this plastic-modified bitumen is better than pure bitumen,” Vasudevan explained.
“Therefore, bitumen can effectively be used for roadway construction,” he added, highlighting that bitumen is the major material used for road construction, and the quality of the road improves with plastic-modified bitumen.
The development of plastic-infused bitumen
Vasudevan thanked late President APJ Abdul Kalam for encouraging him and appreciated the idea of roads made with plastic-infused bitumen. This helped Vasudevan and his team continue their work, who then noted that polymer-modified bitumen worked very well. However, scaling up the process of dissolving plastic in bitumen proved difficult and they had to modify their approach.
“We developed a technique where, instead of dissolving plastic in bitumen, we coated molten plastic over stones. In hot conditions, bitumen is added to the mixture, and it is used for road laying. We took stones and heated them to 170 degrees. The plastic films, cut into 2 to 4 mm sizes, were coated onto the stone,” Vasudevan explained.
“When plastic is added at this temperature, it melts and coats over the stone, forming a plastic-coated stone,” he added. “Once the stone is coated with plastic, bitumen is added, and this mixture becomes the road-laying material. This simple technique makes the road-laying process easier and more effective.”
Vasudevan also highlighted the advantages of plastic-coated stones, saying they stop water from seeping through, thus preventing pothole formation. The plastic holds the bitumen in place, ensuring the road’s durability, he added.
Even though several studies confirm the increased durability and load-bearing capacity of plastic roads, the highlight of such roads is their ability to transform unwanted plastic waste into a valuable resource. While other countries have started to adopt the construction of plastic-infused roads, the only reason hindering their widespread adoption is concerns regarding microplastic pollution.
The next part of the story talks about the waste plastic problem, the effectiveness of plastic roads against plastic waste, and the microplastic concerns associated with plastic roads.
| Plastic Road Series | |
|---|---|
| Part 1 | The Idea and Development of Plastic Roads |
| Part 2 | Plastic Roads Against Plastic Waste |
| Part 3 | Benefits of Plastic Roads Beyond Waste Control |
| Part 4 | State of Plastic Roads in India |
