Industry drives the next turn in India's plastic waste roads innovation

A chemistry professor's technology, developed more than 20 years ago, is being improved upon

It all started more than two decades ago when A P J Abdul Kalam, as a government scientist before he became India’s President, noticed a new technology developed by Rajagopalan Vasudevan, who was then dean and chemistry professor at the Thiagarajar Engineering College in Madurai, that used recycled and shredded plastic for building roads. 

The technology is being used across India to make plastic roads now. Corporate majors like engineering and construction conglomerate L&T have adapted it for their purpose. “For one kilometre (km) of road, I need one tonne of plastic. India has 6 million km (of roads), so the quantity of plastic needed is huge,” said Vasudevan, fondly remembering Kalam, who persuaded Thiagarajar college’s management to construct the first plastic road in the campus as a trial. Vasudevan, now known as the plastic man of India, patented his technology in 2006.
 

While the initial technology mixed bitumen (a black gooey substance combined with gravel to lay roads) with plastic, L&T has improvised it. By combining plastic waste with fly ash and powdered glass, the company makes lightweight, vibration-absorbing blocks that are durable and eco-friendly when building roads. The use of single-use plastic (low-density polyethylene, LDPE) in the process makes the blocks “an excellent choice” for eco-conscious road construction, the company said.
 

“The road is built with two layers: A strong base and a top layer using a mix of hot bitumen and shredded plastic from items like carry bags and milk pouches. The final layer, called bituminous concrete, is made by blending shredded plastic derived from LDPE at a mixing plant and then laid using pavers. Currently, this methodology has been tested on some roads including service roads in highways to see how well it works,”said S V Desai, whole time director and senior executive vice-president (civil infrastructure), L&T.
 

The quality and durability of roads using L&T’s technology is being studied, but presently the cost of production is higher than the regular method that does not use waste plastic. “Using this technology will reduce the mixing plant's production capacity due to increased mixing time to melt and suspend the waste plastic in the mix. L&T is researching this subject to find out if this process can be made more viable as we are committed to sustainability and are pursuing to set new standards in eco-friendly construction and waste management,” said Desai.
 

Vasudevan said some 11 states in India have implemented the plastic technology. According to L&T, this technology has been used to build the Mumbai-Nagpur Expressway Project and in some other projects of the Maharashtra State Road Development Corporation and National Highways Authority of India.
 

“We have laid about 10 km of two-lane service roads using this technology. We have been researching this subject for a while. Our endeavour to build sustainable roads using industrial by-products led to this technology,” Desai added. 

According to industry sources, L&T's effort may make the technology available for mass use. 
 

A blog post on the World Bank’s website said last year India has built more than 2,500 km of plastic roads since 2006 and globally too, plastic roads are “proliferating” in more than 15 countries with projects being piloted or under construction. 
 

“While conventional roads and tire wear constitute a significant source of microplastics, microplastic generation from plastic roads specifically needs to be better understood,” said the blog post.