alt Hacker NewsOf course, you need "forever plastics" to make this work long term. It's like everything else where you have a material with decent compressive strength but weak tensile strength. You need something with some tensile strength to hold it together. That's what rebar does. It's why rebar rusting out destroys concrete structures. The same problem applies to geotextile containment of dirt. If the textile degrades, it's just a pile of dirt, in a place where a pile of dirt isn't enough.
The more traditional approach is to surround dirt or rubble with something that has more tensile strength. Some Egyptian pyramids were built that way. One of them fell down because the outward pressure from the load above was not sufficiently contained. Traditional stone construction of large structures is all about containing that outward push. That's what flying buttresses and bridge abutments do.
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There appears to be a bamboo-derived plastic out there with high tensile strength, but I don't think it'd work for this application, because it degrades within 50 days of being buried in soil. I wonder if being in gravel would delay that, due to the different microbes present?
It seems like there are usually biobased solutions out there, but they aren't as cost-effective or easy to procure as the forever plastics, so organizations don't bother with them. Perhaps some kind of incentive would get us moving in the right direction.
Yep, my first thought when I saw this was "and everywhere this is used, microplastics out to wazoo."
> It's why rebar rusting out destroys concrete structures
That isn't really why. The loss of tensile strength from rebar decomposition isn't what kills it.
Steel expands as it rusts. It breaks apart the concrete via expansion just like freezing water would. If you had a mix of steel and stainless steel rebar, the rusting of the normal steel would destroy the concrete all the same.