Plastic bag ban triggers innovative asphalt

How a possible ban on plastic bags in Karnataka caused two brothers to rethink the potential of urban waste.

Being environmental entrepreneurs was never on the minds of brothers Rasool and Ahmed Khan: they were content running their plastic bag business. Until, that is, a possible ban on plastic bags in Karnataka compelled them to do a rethink. Instead of shutting up shop, they scouted around for viable alternatives.

Intrigued by stories of plastic being used as a constituent of road tar, they began to experiment. With advice from experts at Bangalore University, they started with pothole repair, using a mix of plastic, tar, stones and aggregate. The results were encouraging: the holes stayed filled. Soon their company, now reborn as KK Plastic Waste Management, had won the backing of the Central Roads Research Institute in Delhi, and a patent, too.

The process works like this. Plastic bags are shredded, stored for a week to remove moisture, then mixed with asphalt to produce a tough polymerised compound. The resultant substance is stronger than conventional road surfaces, and lasts twice as long (around six years rather than the conventional three) before starting to degrade.

Since plastic has a tendency to act as a binding agent, it increases the ability of bitumen to hold together, even at higher temperatures. (Plastic melts at 130-140°C degrees, bitumen at half that.) And plastic's water resistance helps prevent the roads from becoming waterlogged, even in heavy monsoons. This means they have fewer potholes, so need repairing less frequently than normal surfaces. All this makes the additional 3% construction cost a wise investment.

Thanks to the backing of Karnataka's Chief Minister, SM Krishna, the brothers were able to resurface a (highly symbolic) 500m stretch of road outside the Rajarajeshwari Nagar Gate, and have since covered 1,500km of the state's roads, using 5,000 tonnes of plastic in the process which would otherwise have gone to landfill – or more likely been burnt.

People give us their plastic waste – they like the idea that it ends up building their roads

They've also boosted the livelihood of traditional kabaadiwalas (waste collectors) and rag pickers, who are paid INR6/kilo for the waste. "People in apartments and schools in Bangalore even give us things like biscuit packet wrappers and milk packet covers", adds Rasool Khan. "They like the idea that what was rubbish ends up in the road."

Rasool is a strong opponent of banning plastic bags. "It's just eyewash. It won't be enforced", he insists. Instead, he advocates collecting plastic from people's doorsteps on a contract basis. This will not only help in the safe disposal of these bags but will also give companies like his the raw material to lay roads successfully. "If the Government takes the initiative, the problem of disposing plastics can be solved in no time. Banning [all] bags is definitely not a solution."

Sapna Gopal is a Hyderabad-based journalist specialising in energy and environmental issues.

This feature appeared in ‘India: Innovation Nation’, a Special Edition produced in collaboration with TERI, Unilever, Interface and Mlinda.

Photo: KK Plastic Waste Management