A Government order in November 2015 has 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 India. The technology for this was developed by the 'Plastic Man' of India, Prof Rajagopalan Vasudevan, and Professor of Chemistry at Thiagarajar College of Engineering, Madurai.

Plastic has slowly become an integral part of all human requirements. Plastic carry bags, packaging material, bottles, cups, and various other items have slowly replaced everything made of other material due to the advantages of plastic. Plastic is durable, easy to produce, lightweight, unbreakable, odorless, and chemical resistant. But it doesn't decompose, that is its major problem. Plastic garbage is commonly seen around the country and has started causing several problems. Plastic waste clogs drains, causing floods. It chokes animals that eat plastic bags, etc. Plastics found in fields blocks germination and prevent rainwater absorption. Recycling plastic can be done only 3-4 times and melting the plastic for recycling releases highly toxic fumes.

By the turn of the century, a lot of noise was being made to reduce the use of plastic and control the waste it was generating. It was during this time when, one evening, Prof. Vasudevan saw a doctor on a TV program saying that plastic 'dissolved' in water bodies caused pollution. Since plastic is a product of petroleum this theory of the doctor had to be false. There was a lot of serious talk about banning plastics all over the country and finding solutions to the waste plastic strewn all over. Laboratory results of mixing waste plastic with heated bitumen and coating the mixture over stone proved positive. He implemented the use of plastic waste on a road constructed inside the premises of his college in 2002. In 2006, the Thiagarajar College of Engineering received the patent for this technology.

The entire process is very simple. The plastic waste material is first shredded to a particular size using a shredding machine. The aggregate mix is heated at 165°c and transferred to the mixing chamber, and the bitumen is heated to 160°c to result in good binding. It is important to monitor the temperature during heating.

The shredded plastic waste is then added to the aggregate. It gets coated uniformly over the aggregate within 30 to 60 seconds, giving an oily look. The plastic waste coated aggregate is mixed with hot bitumen and the resulting mix is used for road construction. The road laying temperature is between 110°c to 120°c. The roller used has a capacity of 8 tons. The advantages of using waste plastics for road construction are many. The process is easy and does not need any new machinery. For every kilo of stone, 50 gms of bitumen is used and 1/10th of this is plastic waste; this reduces the amount of bitumen being used. Plastic increases the aggregate impact value and improves the quality of flexible pavements. Wear and tear of the roads has decreased to a large extent," explains the proud Plastic Man of India.


Source: https://www.thebetterindia.com/43685/plastic-waste-in-road-construction-plastic-man-india-prof-vasudevan/