The first road held together by a cheap, polymer glue made from shredded waste plastic is showing to be incredibly resilient. Built in 2002, the road has weathered major floods, several monsoons, recurring heat waves, and a steady stream of traffic. Even today, it still has not developed the cracks, potholes, and craters that typically appear after it rains.
The environmentally conscious approach to road construction was developed in India around 15 years ago in response to a growing problem of plastic litter. Today, there are more than 21,000 miles of plastic road in India, and roughly half are in the southern state of Tamil Nadu. Most are rural roads, but a small number that have been built in cities such as Chennai and Mumbai.
Every kilometer of this plastic road uses the equivalent of 1m plastic bags, saving around one ton of asphalt and costing approximately 8% less than a conventional road. Dr R Vasudevan, came up with the idea through trial and error, sprinkling shredded plastic waste over hot gravel and coating the stones in a thin film of plastic. He then added the plastic-coated stones to molten tar, or asphalt. The process was patented in 2006.
In India, plastic roads serve as a ready-made landfill for a ubiquitous urban trash. Single use items such as shopping bags and foam packaging are the ideal raw material. Impossible to recycle, they clog city drains and consume space in garbage dumps.
Last November, the Indian government announced that plastic roads would be the default method of construction for most city streets, part of a multibillion-dollar overhaul of the country’s roads and highways. Urban areas with more than 500,000 people are now required to construct roads using plastic waste.
Associated Environmental Problems
However, it’s important to realize that as the roads age, they are likely to shed plastic fragments into the soil and eventually runoff into waterways when they deteriorate when exposed to environmental factors such as light and heat. Once in the soil, these particles may persist, accumulate, and eventually reach levels that can affect the functioning and biodiversity of the soil.
[via The Guardian]