Plastics are synthetic substances derived from petrochemical sources, to be modified according to needs, proving to be a cheap substitute for certain things. But what was developed as a boon earlier has become a bane in today’s world. Incessant use of plastic now poses serious problems related to health and environment, and their being deeply ingrained into our lifestyle and usage makes it difficult to imagine a life without plastics. Many attempts have been made to curb this menace- by decreasing production, implementing a ban on the use, executing reuse of plastic material, but none have proven to be effective so far.
To deal with this menace to some extent in India, NHAI (National Highway Authority of India) recently declared development of a stretch of highway by mixing plastic in asphalt and bitumen. People who so far were unaware of such a practice will attribute this development to a country apart from ours. But this was first conceived and brought to practice in our country by a businessman located in Bengaluru. K. Ahmed Khan came up with using plastic on roads. His innovation garnered a lot of attention and praise. Its use was further developed and promoted by R. Vasudevan of Thiyagaraj College.
Plastic is used on roads by mixing with bitumen before laying roads. Usable plastic (less than 60 micrometers/microns thick) is first separated from the waste stock. Plastic with a thickness less than 60 microns is selectively shredded to pieces of a required size for further processing. It is then heated at around 160 degree Celsius and mixed with bitumen. This bitumen is then, with asphalt, laid down as roads.
Mixing plastic provides a whole range of benefits. It increases the durability of roads, decreases road fatigue, allows them to stay intact for long by acting as a binder, more resistant towards rain and temperature shock. Apart from benefits to the roads, the use of plastics in road construction also generates jobs for rag pickers, decreases the amount of bitumen used, roads run for longer and require less maintenance, and the obvious benefit is the use of plastic.
However, the pros of using plastic do not come without its cons. Plastic use in roads causes leaching of chemicals into soil on exposure to water (similar to burying plastics), chlorine present in plastics is released as toxic hydrogen chloride gas during the process of laying roads, water impervious property prevents percolation causing water logging, wear and tear causes release of polymer particles, causing particulate affected air pollution.
Adding bitumen to plastics sure appears as a solution to plastic menace, but it is just the relocation of plastic from ugly looking dump yards to somewhat cleaner looking roads. This does not put an end to the problem created by the mere presence of plastics. The plastic is still very much there and causing problems, albeit in a new fashion and with different effects. How this problem is recognized and dealt with, is a new challenge.
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