That it can be made into something more expensive doesn't imply that it is also environmentally sound.
In fact, those are almost always mutually exclusive goals.
My question is about what will be used for roads, and whether acquiring that product will be more environmentally sound.
I'm not immediately opposed to the technology. I'm just at least as skeptical as all scientists should be.
it's possible i'm misunderstanding, but you seem to be asking whether making crushed stone is more or less environmentally damaging than recycling old concrete. the answer is that neither of them results in significant environmental damage in itself, but trucking them to construction sites does
also can you elucidate which goals you meant to say were usually mutually exclusive? it isn't clear from context
also, i asked two questions in my previous comment that you haven't answered: are they offering you money for your old concrete? how much are they paying?
They are offering money. As for how much, I imagine it depends on the area. All things gravel and stone are expensive at the moment. People are getting caught stealing sand, that's the world we're in today.
it's not true that gravel, crushed stone, and sand are expensive, by most definitions of 'expensive'. they cost pennies per kilogram. yes, that's enough for people to make a profit from stealing
something like 15% of the material that gets carted to landfills is old concrete
generally speaking, old concrete is used in new concrete as (very) coarse aggregate. alternative coarse aggregate is mostly angular crushed stone, like the track ballast you see around railroad tracks. this is made by dynamiting deposits of limestone, granite, or basalt and feeding it through a rock crusher. while this sounds violent and energy-intensive, it's nothing compared to running a cement clinker kiln. most of the cost of coarse aggregate is from the cost of shipping it, not the cost of the energy needed to crush it; as wp says
> Large stone quarry and sand and gravel operations exist near virtually all population centers due to the high cost of transportation relative to the low value of the product. Trucking aggregate more than 40 kilometers is typically uneconomical