After introducing ingenious plastic-reuse mechanism in road construction, Bengaluru is now falling behind

In a shop on a narrow lane in Jolly Mohalla in KR Market, Asif Ali Khan monitors workers segregating plastic cups, covers, broken buckets and pipes from a heap of plastic waste. His 30-year-old shop is among the many plastic collection centres in the city that collect, clean, sort and send the plastic for recycling.

Until 2015, Khan had two prominent customers for his plastic waste: plastic recycling units and those supplying plastic mixed bitumen for road construction. While recycling units continue to be his customers, the business from road construction has stopped. In 2015, the city’s prominent promoter of plastic roads – KK Plastic Waste Management – stopped laying plastic roads. And, that was because its MoU with the BBMP to supply plastic mixed bitumen expired. The BBMP did not renew the agreement.

KK Plastic built many roads in the city using plastic waste as part of its agreement with the BBMP. The stretch of Jayamahal Road near the TV Tower was arguably the first Indian road built using plastic waste. KK Plastic still holds the patent for KK Poly Blend, a polymer made of plastic carry bags and packing material that is blended with bitumen.

India’s first commercial experiment with building plastic roads was carried out in Bengaluru. That was in December 2002. Although a few players emerged later, the city where the technology took birth seems to have quietly abandoned the idea. As irony would have it, this simple solution to plastic-disposal did not gather momentum even at a point when disposing used-plastic has become a huge challenge in cities.

That the Bengaluru International Airport — which sought and received five tonnes of plastic waste from the city corporation last week — is reviving the idea has come as a ray of hope as far as disposal of plastic waste is concerned. Interestingly, BIAL borrowed KK Plastic’s technology for the purpose. “We require over 50 tonnes of plastic to pave approximately 50 km of internal roads. This will go a long way in reducing the carbon footprint,” said a spokesperson.

Meanwhile, the roads built with plastic have stood the test of time. A 2009 study carried out by the Central Pollution Control Board observed that polymercoated bitumen roads “were performing very well in spite of their age” and “under similar conditions most of the bitumen roads are not performing well at all. These (polymer-coated bitumen) roads have not developed even small cracks and potholes,” the study found.

Prof Sridhar Raju, head of civil engineering at BITS Pilani, Hyderabad, said his research had shown that polymerised roads work best in cities. “The durability is high as the plastic component stiffens the bitumen, providing no room for water to seep in. I, however, do not recommend such components on highways as frequent movement of heavy vehicles will create cracks in the road,” he observed.

Those involved in the business of making plastic roads say that cost is not a factor either. “Ideally, mixing plastic in bitumen can save up to Rs 10,000 per kilometre. But, often, contractors add cost of plastic without deducting the amount on bitumen saved,” Rasool Khan, proprietor of KK Plastic, said.

KK Plastic, which supplies this product to projects in Karnataka and elsewhere, claims to have laid 3,500 km of polymer roads using about 15,000 tonnes of plastic. While those in the industry say “using plastic is not the problem, but disposing it is,” the counter argument follows that laying roads using plastic will not solve the mounting plastic problem.

“I agree constructing polymer roads is a feasible model and is being used extensively, but polymer roads alone will not solve the plastic problem. Since the quantity of plastic used in making roads is very less, we cannot be under the impression that a heap of plastic is absolved by a road,” said Capt RR Doddihal, retired chief engineer with the state’s Public Works Department.

According to plastic bitumen manufacturers, the quantity of processed plastic shreds required for laying one kilometre of road is about 1.5 tonnes. The actual waste plastic required to generate 1.5 tonnes of processed plastic is about three to four tonnes. While the exact figure on the plastic waste generated in Bengaluru is not available, plastic amounts to approximately 20% of about the 3,000 tonnes of waste that goes to landfills every day.

Shekar Prabhakar, cofounder and managing director of Hasiru Dala Innovations, said that about 4,300 tonnes of recyclable plastic is traded in Bengaluru every day and is sourced from both inside and outside the state.

Though polymer roads are economical, the challenge is in following the specifications of road laying, said Prabhakar. “The heated plastic has to be used in a particular way so that it bonds with bitumen. It requires a good contractor who precisely follows the road-laying specifications (heating bitumen up to 80 degrees centigrade), failing which it might result in a shoddy job,” he said.

While KK Plastic says the BBMP has not sourced the material since 2015 and has stopped making roads using plastic, BBMP officials claim they are continuing to make plastic roads. “For two years between 2015 and 2017, we did not make plastic roads as the MoU between KK Plastic Manufacturers and BBMP lapsed. But in the last two years, we have asphalted about 200 km of the 1,400 arterial and subarterial roads. Of them, about 70% of the roads were asphalted using plastic and bitumen components,” S Somashekar, chief engineer (road infrastructure), BBMP, said.

Asked where BBMP sources the polymer material, Somashekar said there were 2-3 suppliers and that KK Plastic was the major supplier. The company however denied this.