The abundance of plastic waste dumped into the environment and its harmful effects require urgent action. In response, many countries have actively taken responsibility for recycling as much plastic as possible. There are different ways of using recycled plastic, one of which is to use it in the construction of roads.
India is one of the few countries that has started using recycled plastic in road construction in recent years. In fact, a November 2015 government order made it mandatory for the country's road developers to use plastic waste along with bituminous mixtures for road construction. On the other hand, some similar projects are also being initiated by other countries.
Feasibility of the Idea
Plastic being used in road construction (Image courtesy: indiatimes)
Plastic is a man-made material, but it is also something that cannot be destroyed. Most of the waste created by humans contains plastic waste that ends up choking stray animals to death, clogging sewers and just causing mayhem. Clogged drains lead to flooding, while plastic in fields blocks germination, thus preventing the absorption of rainwater.
Considering the complexity, it seems like a perfect solution to put plastic into the heated mixture of bitumen and coating and use it in road construction. But how practical is this? Well, the answer is quite positive. While some may point out that spreading an environmentally harmful material on the roads could be even more disastrous; The truth is that many roads built in India in recent years have deposited plastic waste on the roads without any problems being reported.
How is it different from the conventional method?
View of an Indian road built from plastic waste (image courtesy: thebetterindia)
Building one kilometer of standard bitumen road requires 10 tonnes of bitumen, while using recycled plastic can build a 3.75 meter wide road, using 9 tonnes of bitumen and 1 tonne of plastic waste for each kilometre. Interestingly, 1 ton of bitumen costs between INR 50,000 and INR 60,000 (in India). So for every 1 kilometer you save thousands of rupees.
Furthermore, 1 tonne of plastic waste is equivalent to 10 Lacs carry bags and hence people are forced to sell the plastic they use for domestic purposes. This has led to thousands of people getting involved in collecting and destroying plastic waste.
Road construction process using plastic waste
Plastic Waste Collection: The first step involves collecting items categorized as plastic waste. It includes 60-micron-thick bags and cups, hard and soft foams, laminated plastics like biscuits and chocolate wrappers.
Crushing:
The collected plastic is cut into sizes from 2.36mm to 4.75mm using a shredder.
Heating:
The aggregate mixture is then heated to 165 to 170 degrees Celsius and transferred to a mixing chamber while the bitumen is heated to 160 degrees Celsius to prevent weak bonding.
Coating:
In the mixing chamber, the crushed plastic evenly covers the aggregate in 30-60 seconds and has an oily appearance.
Construction:
The plastic waste mixture is combined with the bitumen mixture and the resulting aggregate is used to build the road at 110 to 120 degrees Celsius.
Plastic Road Projects:
Across the world, there have been independent attempts to bring a change to the conventional road construction method while making better use of recycled plastic waste. Listed here are some of those prominent projects that have been initiated and implemented to date.
1. Initiatives taken by Plastic Man of India:
Prof. Rajagopalan Vasudevan, India's Plastic Man (Image courtesy: thebetterindia)
Professor Rajagopalan Vasudevan, Dean and Head of the Department of Chemistry, Thiagarajar College of Engineering (TCE), Madurai, is known as India's Plastic Man for introducing a revolutionary solution to plastic pollution. In 2002, he built the first plastic asphalt road within the university campus which has remained intact to this day. Although TCE holds the license for this technique, it is generally licensed free of charge. The same technique was adopted by the Central Pollution Control Board and the Indian Highway Congress.
To date, more than 3,000 miles of roads have been built in 11 states across the country using shredded plastic waste. He even developed a plastic monoblock technology that uses only plastic and stones at high temperatures to build monoblocks, with a load capacity of 300 tons.
two. KK Plastic Waste Management
While the above attempt by Prof R Vasudevan was made to develop the technology, another attempt was made by a company called KK Plastic Waste Management Limited to take care of recycling. It is the only company with exclusive patented technology for reusing plastic waste for road construction since 2002.
The company has plastic recycling plants in Bengaluru that process up to 30 metric tonnes of plastic daily. The organization is responsible for collecting plastic waste from all possible sources, concluding contracts and then supplying the product to authorities who use this mixture in road construction.
3. The PlasticRoad Consortium
The PlasticRoad Project (image courtesy: plasticroad)
The PlasticRoad Project is a group effort where the goal is to design each necessary road component with as much recycled plastic as possible. Unlike the previously mentioned methods where plastic waste was mixed with bitumen, here the approach is to construct hollow spaces with recycled plastic. The project is the result of a partnership between three companies, namely:
• KWS : It is the market leader in asphalt production in the Netherlands as well as in road construction. It is committed to building large, complicated and multidisciplinary projects along with small projects for governments and individuals.
• Wavin : It is the European market leader in the supply of plastic pipe systems and also offers a wide range of products for sustainable stormwater management.
• Total : It is the global energy producer and supplier, a leading oil and gas company and the second largest solar energy operator in the world, along with SunPower. It deals with oil and gas production, refining, petrochemicals and marketing.
In this project, the objective is to build prefabricated and hollow spaces and lay them in the form of blocks for road construction. Furthermore, if the plastic does not have the necessary rigidity, the plan is to add sand or gravel to the mix.
• The project states that the plastic roads will feature:
• 70% faster road construction
• Dual use of hollow space for cables, pipes or water storage
• Little or no maintenance
• Expected useful life of roads 3 times longer
• 4 times lighter than traditional road structure
Although the partners have announced the project publicly, they still have to wait to prove whether the idea is sufficiently viable and the aim is to build a prototype by the end of this year. The idea has also received some criticism for not being practical enough due to the nature of plastic and its unsuitable properties. The project even has a chance to change the way people think about road construction.
Conclusion
Plastic is non-biodegradable waste and using it in road construction can actually solve several problems globally. With the advancement of technology and engineering techniques, nothing seems impossible. By now, it is quite clear that humans have ruined the environment in every possible way through excessive use of technology and now it would be interesting to observe how they use the same technology to solve the problems they have created.