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

Question

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

Answer 1

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.