When plastic was first discovered, it was considered to be a revolution in the world’s industries. It was extremely durable, light weight, water and chemical-resistant, insulator and versatile. It could be moulded into almost any shape. Its properties could be modified to satisfy particular technical needs. Deemed as a boon for the packaging industry, it was readily adopted.                                                     

However, the very same qualities of plastic have now become a menace for this planet. Due to the ability of plastic to withstand extreme physical conditions, it is non-biodegradable. This means that it cannot be broken down into simpler substances by microbial action. Hence, a plastic bag once manufactured, will not decompose and stay in the environment for years together, doing it great harm. They cause both environmental and aesthetical damage to our surroundings.A large number of fish, marine birds and animals like cattle and turtles are choked to death everyday by swallowing plastic bags. As many as 1000 plastic pieces have been found inside dead animals.

In order to rid the environment of plastic garbage, Ahmad Khan of India has developed a technology to burry plastic bags with roads. He has developed a processed plastic called Polyblend, which modifies bitumen’s properties and increases road life and performance.    

Invention of Polyblend

Ahmad Khan, owner of KK Polyflex, a firm based in Bangalore, India had been manufacturing plastic sacks for over twenty years. He came to realize the hazards of plastic and the gravity of plastic solid-waste disposal problems. Ahmad Khan, along with his brother Rasool Khan and a chemical Engineering friend developed a recycled modified plastic with some proprietary stabilizers, called Polyblend. Subsequently, Ahmad Khan sought help from Prof CEG Justo of Bangalore University and Chemical Engineering students of R.V. College of Engineering. They conducted various experiments with blends of Polyblend and bitumen coal. It was concluded that polyblend, when mixed with bitumen, enhances its properties, thereby increasing road-life and performance.

Basic Process

The raw material for Polyblend is any kind of plastic film waste. However, different types of plastic wastes, like plastic bags, bottles, buckets are segregated. The waste plastic is fed into shredding machines. Once powdered, the different types of plastic wastes are mixed together. This powder is mixed with hot bitumen and other prescribed additives in a specific proportion to form aggregates used for laying roads. The final step is carried out in the same way as ordinary tar roads are laid. Since the plastic is only shredded, and not burnt, the process eliminates chances of release of toxic gases into the atmosphere.

Collection of Waste Plastic

The city of Bangalore produces over 35 tonnes of waste plastic every day. However, out of this, only about two tonnes of plastic manages to reach the waste management company for the manufacture of Polyblend. In order to encourage more collection of plastic, KK Plastic Waste Management Company collaborated with many schools and the Karnataka State Pollution Control Board. They have installed dustbins in schools where children bring and dump their household plastic waste. Apart from this, Ahmad Khan employed junk dealers who collect plastic wastes from homes and pay in return for the waste.

Moreover, rag-pickers who collect garbage from the streets earlier used to be paid about 40 paise per kg of waste. KKPWM now offers them Rs.6 –Rs. 12 per kilogram of plastic waste, depending upon the quality of the waste.

Advantages

Plastic serves as a modifier for bitumen and alters its properties to increase the road life and performance. Plastic enhances the binding capacity of bitumen which enables the roads to withstand higher loads. This also increases the effective road and fatigue life. Usually highway roads last for about 4-5 years. However, the average life of plastic roads is expected to be about ten years, just double of that of ordinary tar roads. Plastic also increases tar’s ability to withstand high temperatures. Plastic-bitumen mix stays stable at temperatures as high as 55 C.

Since plastic is resistant to water, it makes the roads more impervious to water. Plastic roads are three times more water repellant than the ordinary tar roads. They prevent water-logging and hence, decrease the number of road repairs required. These roads can therefore be of immense help in hot and humid tropical countries where high temperatures and heavy rains adversely affect road life. After conducting vigorous tests in the laboratory, The Central Road Research Institute in New Delhi, India has endorsed this technology. The experiments revealed that the Marshall Stability Value of polyblend-bitumen blend is almost thrice that of ordinary bitumen.

Success Story

After 2002, when the first 1 km long plastic road was laid in TV Tower Road of Bangalore, KK Plastic Waste Management Company  laid 40 more km of roads in the next two years at twelve different places around the city. This year, about 47 roads in Bangalore will be upgraded and turned into plastic roads. The waste management company now also has an agreement to lay down 800 km more of Polyblend roads around the city

Impressed by the success of plastic roads, Sheila Dikshit, the chief minister of New Delhi, also agreed to lay plastic-bitumen roads in the national capital. The advent of plastic roads has also spread to other states of the country, like Tamil Nadu and West Bengal. In West Bengal, the Hubli Mahanagar Palika (meaning: Hubli Municipal Corporation) laid down 20 km of plastic roads to test their viability for the future.