Guwahati: A pilot project to construct 100 metres of road using waste plastic mixed with bitumen was launched by PWD minister Himanta Biswa Sarma on the Kahilipara-Dakhingaon road on Thursday.

Sarma said, "This technology is suitable for Assam as we have heavy rainfall which damage roads. The project will help decrease environmental impact from plastic waste, reduce construction costs and build stronger and durable roads. If the pilot project is successful, we will apply this technology while constructing roads across the state."

This is the first time that the Assam public works road s department is using this technology, following the example of the Meghalaya government which constructed 1km of a road in Nongkynjang using plastic waste. Altogether 4,000km of such roads have been also laid in Madhya Pradesh.

Manipur is also planning to use plastic waste in building roads. Manipur will be the second in the Northeast after Meghalaya to use plastic waste in road construction.

A study by a city-based NGO revealed that 22,000kg of plastic waste are generated here every day. The environment department estimated that only 60 per cent of this waste is recycled. The rest is deposited in garbage dumps or burnt, causing environment pollution.

Plastic pollution affects wildlife, marine life and their habitat while discarded plastic clogs drains, resulting in artificial floods.

PWD assistant executive engineer (new technology cell) Prahlad Kakati said, "The process is very simple. Waste plastic bags are collected from households, roads, garbage trucks, dumping grounds, rag-pickers and waste buyers. The collected plastic is sorted according to their thickness. Generally, polythene of 60 microns or below is used in road construction. The plastic is cleaned and shredded to a size between 2.36mm and 4.75mm. The aggregate mixture is heated to 165 degrees Celsius, bitumen of standard specification is added and then the shredded plastic is added. The amount of plastic to be added is 8 per cent of the bitumen. The resulting mixture is laid on the road surface at 110 degrees to 120 degrees Celsius."

Waste plastic bituminous mixture helps build stronger roads with better load-carrying capacity, resistance to rainwater and water stagnation, increased binding and better bonding of the mixture, reduction in pores and potholes, reduced cost of construction and insignificant maintenance costs, apart from no plastic waste disposal problems.

Replacement of bitumen by plastic waste will lead to a saving of around Rs 21,000 in cost of bitumen per km (single lane of 3.75 m width).

An Indore-based company has supplied the shredded plastic for the pilot project and is in talks with the government to set up a plant here.

A central government order in November 2015 had made it mandatory for all road developers in the country to use waste plastic, along with bituminous mixes, for road construction. This is to help overcome the growing problem of plastic waste disposal in the country.

The technology for this was developed by the Plastic Man of India, Rajagopalan Vasudevan, a professor of chemistry at Thiagarajar College of Engineering, Madurai.