The news, and my comments on that news, have been pretty bleak of late, so I thought I would look for evidence that good things are also happening in the world. (Probably even in the U.S.)
And I found some things!
I particularly looked for technological breakthroughs that might mitigate climate change or otherwise represent environmental progress, and this one struck me as especially promising, not least because I’ve been driving in “pothole city”–aka Indianapolis.
Jambulingam Street, Chennai, is a local legend. The tar road in the bustling Nungambakkam area has weathered a major flood, several monsoons, recurring heat waves and a steady stream of cars, trucks and auto rickshaws without showing the usual signs of wear and tear. Built in 2002, it has not developed the mosaic of cracks, potholes or craters that typically make their appearance after it rains. Holding the road together is an unremarkable material: a cheap, polymer glue made from shredded waste plastic.
Jambulingam Street was one of India’s first plastic roads . The environmentally conscious approach to road construction was developed in India around 15 years ago in response to the growing problem of plastic litter. As time wore on, polymer roads proved to be surprisingly durable, winning support among scientists and policymakers in India as well as neighboring countries like Bhutan. “The plastic tar roads have not developed any potholes, rutting, raveling or edge flaw, even though these roads are more than four years of age,” observed an early performance reportby India’s Central Pollution Control Board. 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 have also been built in cities such as Chennai and Mumbai.
According to this and other articles, so-called “modified” asphalts, consisting of virgin polymers (and sometimes ground-up old tires), have been used here in the U.S., and have been found to perform well: Illinois has used them to build high-traffic roads used by lots of trucks, and Washington State uses them for noise reduction. They tend not to buckle in extreme heat the way conventional roads do.
But the modified asphalts being used here are pretty costly–they can increase the cost of a road anywhere from 30-50%. The paving being used in India costs less than conventional roads.
While polymer roads in the US are made with asphalt that comes pre-mixed with a polymer, plastic tar roads are a frugal invention, made with a discarded, low-grade polymer. Every kilometer of this kind of road uses the equivalent of 1m plastic bags, saving around one tonne of asphalt and costing roughly 8% less than a conventional road….
In India, plastic roads serve as a ready-made landfill for a certain kind of ubiquitous urban trash. Flimsy, single-use items like shopping bags and foam packaging are the ideal raw material. Impossible to recycle, they are a menace, hogging space in garbage dumps, clogging city drains and even poisoning the air.
That same plastic trash has become a huge hazard in the oceans.killing marine life and littering previously pristine beaches. In the middle of the Atlantic, there is an area that spans the distance between Virginia to Cuba called the Great Atlantic Garbage Patch: it has up to 26 million plastic particles per square kilometer.
Turning plastic trash into cheaper, longer-lasting roads–now that should make us smile! (At least until civil engineers and construction special interests block adoption of the technology here….)Comments