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[dupe] A man who paves India's roads with old plastic (theguardian.com)
33 points by nwrk 3 months ago | hide | past | web | favorite | 14 comments



Wasn't this discussed yesterday?

https://news.ycombinator.com/item?id=17490990


But isn't the problem with plastic in the ground that chemicals would leech out of it and debris would break off from it and be ingested by animals and humans? Is a road that much better than dumping it in the ground away from humans and animals? I worry about physical changes to the road over time. Is it safe to inhale the dust that is generated from wheels rolling over a sun-burdened piece of plastic for years?


from the article:

To environmentalists who believe that the technology could be harmful because of toxic fumes from plastic residue, Dr Vasudevan points out that the plastic used is softened at 170C. “Plastic decomposes to release toxic fumes only if it is heated at temperatures above 270C (518F). So there is no question of toxic gases being released,” he says. Since plastic coats the stone and interacts with the hot bitumen, it’s properties change and it doesn’t break down when exposed to light and heat.


You don't need toxic fumes, plastic doesn't go away. It breaks down into smaller and smaller pieces and contaminates the environment.

See: https://en.wikipedia.org/wiki/Microplastics


>The bitumen-modified plastic improved the tensile strength of the road by making it more durable and flexible. Plastic also prevented pothole formation. When the layer of molten plastic filled the space between the gravel and bitumen it thwarted rain water from seeping in and causing structural defects.

Seems like it would break down less than a regular tar-only road and last longer to boot.


It seems like it will help keep the overall rigity of the road but it says nothing about how the material will break into pieces on the exterior layers. Plastics are known to cause cancer and other harm to living things when ingested, and my curiosity is if plastic could be more damaging than the thing it replaces.


Myself, I'm not convinced plastic is more harmful to the immediate environment in this application than the tar/bitumen itself. It does seem the issue of plastic shedding into the environment has not been investigated enough, but does tar not leech toxic chemicals as well?


Thanks but I said dust not fumes.


Another part of the question worth asking: is it worse than bitumen? We're already accepting an environmental impact from the roads, does this improve on that or not?


This is terrible. Plastic is forever and breaks down into smaller and smaller pieces entering the environment.


The article is discussing a technique used to dispose of waste plastic. In other words plastic that would exists in macro and micro form regardless of its use to improve roads.


It seems from the article, they have considered that and concluded that since plastic becomes part of the bitumen, and does not exist as plastic particles.


Unless it has chemically changed considerably it's a problem. My impression is they are saying "don't worry, chunks aren't going to break off because it's melted into the bitumen" and are wholly ignoring the micro scale.


That would be an improvement considering the garbage situation in India.




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