Recycling opens new road to stave off plastic threat
But Centre’s guidelines for laying roads with shredded plastic have been ignored by civic bodies and others despite benefits of a patented process
Since 2001, R. Vasudevan, Dean, Thiagarajar College of Engineering, Madurai, and his team at the Centre for Studies on Solid Waste Management (CSSWM) have come out with a research finding that promises to address two pressing problems together: bad roads and burgeoning plastic waste.
Dr. Vasudevan, known as the ‘Plastic Man of India,’ has been praised by Prime Minister Narendra Modi and also awarded the Padma Shri this year.
His process, patented in 2006, involves mixing shredded plastic with hot gravel and adding it to molten asphalt. Plastic and bitumen bond well because both are petroleum products. This combination enhances the road’s ability to carry weight, as well as its life.
‘Plastic roads’ constructed since 2002 have not developed blisters or potholes, says Dr. Vasudevan. One tonne of plastic waste is used with nine tonnes of bitumen to lay 1 km of road. This means a saving of one tonne of bitumen (approximate cost ₹50,000).
The only unusable plastics are polyvinyl chloride, which releases harmful dioxins when heated up.
The plastic road technology, when it was patented, evoked excitement as it came as an answer to the nagging problem of waste plastic disposal. A performance appraisal by the Central Pollution Control Board (CPCB) showed that plastic roads did not develop familiar defects: potholes, rutting, ravelling or edge flaw, even after four years.
Besides opening up an avenue to use plastic waste, the roads built with polymerised asphalt last longer. The waterproofing quality ensures that the water doesn’t seep down, thus reducing wear and tear.
While asphalt roads are expected to last for three years, roads with plastic as an addon aggregate ensures longevity of seven years. The waterproofing makes the roads ‘pothole-proof’. Roads with the polymerised mix also don’t crack or melt under extreme heat conditions.
An estimated 15,000 tonnes of plastic waste is generated in India every day. If all the roads built in the country between 2013 and 2016 had used 6%-8% plastic waste, as stipulated by the Indian Roads Congress (a standards body of engineers and professionals) the country could have managed to take care of more than 330,605 tonnes of plastic scrap, according to an expert.
“This is a conservative estimate. Roads consist of many layers. If we factor in all the layers with bitumen and upto-date data about roads, the volume of plastic waste removed from the environment would be much higher,” according to an engineer, who did not wish to be identified.
Fails to take off
Over the years, however, adoption of the technology has been spotty. In some States, such as Tamil Nadu, nearly half the roads are made of plastic, as per official figures. In Delhi, on the other hand, it has not moved beyond pilot demonstrations.
In Tamil Nadu, the late Chief Minister Jayalalithaa instructed the District Rural Development Agency to use the plastic road technology. Such roads made up about 1,500 km in 2004-05, says Dr. Vasudevan. According to an official report, over 16,000 km of plastic roads were laid in Tamil Nadu till 2014. Roads are constructed using waste plastic in Himachal Pradesh, Madhya Pradesh, Kerala, Meghalaya and in neighbouring Bhutan.
The Centre told Parliament in August that the Roads Ministry “encourages” the use of waste plastic in National Highways construction, especially on National Highways within a 50 km periphery of urban areas that have a population of 5 lakh or more. The guidelines for the use of waste plastic stipulate a stretch of at least 10 km as a pilot project for assessment, so as to make it compulsory in highways contracts. So far, however, no National Highway has been constructed with waste plastic and no target has been set for it during 2017-18.
It isn’t that the Centre is not convinced of the technology. The Indian Roads Congress has released the standard, IRC: SP: 98: 2013, for application of plastic road technology. In 2015, the Union government issued guidelines on plastic use with hot mixes for bitumen roads around urban areas. In case of non-availability of waste plastic, the road developer would have to seek approval from the Ministry of Road Transport and Highways for bitumen-only roads.
So, why haven’t civic bodies, road contractors and the Public Works Department followed the guidelines?
“The Central government has issued a directive that by default, plastic waste should be part of the bitumen mix while laying roads…be it panchayat, Public Works Department or even public-private partnership projects like the Outer Ring Road in Hyderabad. It would save valuable foreign exchange as well. But the directives have been ignored,” says Dattu Panth, Superintendent Engineer, Greater Hyderabad Municipal Corporation.
“The first to cry off the plastic-mix stipulation are the contractors who say they will suffer a loss if they follow the procedure. Part of their fear is that the roads will last longer and they will not be able to make money. Urban civic bodies are spending thousands of crores of rupees on roads and this revenue stream will dry up. The other part of the problem is that shredded plastic is not easy to come by,” says a civic engineer who declined to speak on the record.
Contractors say they will suffer a loss if they follow the procedure. Part of their fear is that roads will last longer and they will not be able to make money
Satish Chandra, Director, Delhi-based Council of Scientific & Industrial Research (CSIR)-Central Road Research Institute says there are enough enabling legislations to require use of plastic in road laying. But lack of enforcement of rules by municipal authorities means that there isn’t enough shredded plastic available. “Segregation, cleaning, and cutting of plastic is necessary to make it available as a raw product. The technology is well understood and scalable but, like the helmet law, needs enforcement,” he adds.