Eli5: Why can’t plastic be recycled and used as a road or concrete floor base?


When I was a builder we used to pour a concrete ring foundation with reinforcing steel in it and then fill up the center of the ring with river stone and compact it. Then we would pour a 100mm (4inch) thick slab on top with reinforcing mesh in it. Is there any reason the hard fill under the concrete couldn’t be recycled plastic chips the size of stones? (Same with under road surfaces). I feel like this would solve our plastic waste problem.

In: 5

4 Answers

Anonymous 0 Comments

Plastics can be recycled into all sorts of stuff. The problem is that is just too expensive to do it. Pretty much everything about recycling plastic and such you ever been fed is mostly BS. Its very difficult and expensive to recycle plastic and very little of it is/was every recycled. The plastic that was recycled was often done in China (China would import waste plastic from the rest of the world to recycle) but the economics are so bad that this is no longer viable.

Its a money problem. People are trying to solve this now across the world, but right now its just not hitting the right financial numbers to make recycling plastic a profitable venture, so many recyclers are subsidized to offset losses… but mostly, plastic just goes into landfills.

Anonymous 0 Comments

This is one of the ways to recycle plastics. And it is done in some cases. Both as a simple fill and as agregate for concrete or resin. However the material properties of plastic is far from tha material properties of stone. Plastic will usually deform under pressure. While gravel stay porous and support the weight over time the plastic will sag as it collapses into the pores. So the slab you poar over top will start to crack as it becomes uneven and the drainage will be destroyed so the water will flow over top of the slab, or under the entire site digging out the dirt. So you can not just simply replace the gravel with plastic waste.

Anonymous 0 Comments

Hint. Any plastic that has been in contact with oil food, greases, and it’s smeared with anything that sticks to it, turns it into a unrecyclable thing. No matter how much you wash it, it will have something ELSE that make it worse or impossible to reuse.

Most of our thrash ends up so dirty it doesn’t makes any sense to recycle it. Like 90% or more.

Aluminum has to be molten back and most stuff ends up burned on the heat. The rest floats over the alu, and it’s just removed. Alu is soon much better to recycle. Same as glass. Need so much temp.

Anonymous 0 Comments

You could probably grind up the unrecyclable plastic and use it as a road base. But that doesn’t really solve the problem of microplastics getting into our ecosystem.