5 ms·

Given that asphalt construction is made out of mostly waste materials, is nearly 100% recyclable, can be patched in-situ, requires very little maintenance, requ

by deelowe 11y ago

Given that asphalt construction is made out of mostly waste materials, is nearly 100% recyclable, can be patched in-situ, requires very little maintenance, requires very little skill to install/maintain, and is much more durable than glass, there's no way the TCOs are even remotely comparable.

deleted 11y ago
[deleted]
Retric 11y ago
Asphalt is a product from crude oil; as such it's got finite supply and is likely to go up significantly in costs over time. It's actually used on roofs which are becoming less common for various reasons and breaks down in sunlight. PS: Nothing says they need to use glass, just a cheap durable and translucent substance.
- bzbarsky 11y ago
  OK, can you name a cheap, somewhat durable, and translucent substance that's not glass? The typical translucent substances people use in practice are various kinds of glass, plexiglass (not durable; scratches up a lot), transparent ceramics of various sorts (generally not cheap), gems like sapphire (not cheap, especially for large-scale applications). Anything I'm missing?
  - Retric 11y ago
    Lacquer wood finish comes to mind, though tar is hardly durable. Not 100% on the specifics but people already use concrete sealant on roads so traction and cost wise it's in the ballpark. Don't forget Silicon is really quite tough so your really looking for something that can sit outside for 20 years vs. trying to protect fragile components.
    - bzbarsky 11y ago
      Silicon is not necessarily tough in the sense of https://en.wikipedia.org/wiki/Toughness https://en.wikipedia.org/wiki/Toughness -- it really depends. The hard problem in road surfaces is not the sitting outside for 20 years. Glass, even cheap crappy glass, handles this last just fine; see windows in houses. The hard problems are dealing with repeated time-varying mechanical stress and dealing with thermal expansion (windows can play fast and loose with this by leaving expansion space around the glass inside the frame).
      - Retric 11y ago
        Crystal silicon not steel, but it's reasonably close to concrete. And concrete is the high end road surface vs. asphalt. Crystal silicon [.6 - 1.3KIc (MPa · m1/2)] https://lirias.kuleuven.be/bitstream/123456789/355152/1/Thermomechanical+properties+and+fracture+in+single+crystal+silicon+-+REVIEWED.pdf https://lirias.kuleuven.be/bitstream/123456789/355152/1/Ther... (Page 12) Concrete [0.2-1.4 KIc (MPa · m1/2)] https://en.wikipedia.org/wiki/Fracture_toughness https://en.wikipedia.org/wiki/Fracture_toughness
- deelowe 11y ago
  Asphalt is nearly 100% recycled.

by deelowe 11y ago

deleted 11y ago

[deleted]

Retric 11y ago

Asphalt is a product from crude oil; as such it's got finite supply and is likely to go up significantly in costs over time. It's actually used on roofs which are becoming less common for various reasons and breaks down in sunlight. PS: Nothing says they need to use glass, just a cheap durable and translucent substance.

bzbarsky 11y ago
OK, can you name a cheap, somewhat durable, and translucent substance that's not glass? The typical translucent substances people use in practice are various kinds of glass, plexiglass (not durable; scratches up a lot), transparent ceramics of various sorts (generally not cheap), gems like sapphire (not cheap, especially for large-scale applications). Anything I'm missing?
- Retric 11y ago
  Lacquer wood finish comes to mind, though tar is hardly durable. Not 100% on the specifics but people already use concrete sealant on roads so traction and cost wise it's in the ballpark. Don't forget Silicon is really quite tough so your really looking for something that can sit outside for 20 years vs. trying to protect fragile components.
  - bzbarsky 11y ago
    Silicon is not necessarily tough in the sense of https://en.wikipedia.org/wiki/Toughness https://en.wikipedia.org/wiki/Toughness -- it really depends. The hard problem in road surfaces is not the sitting outside for 20 years. Glass, even cheap crappy glass, handles this last just fine; see windows in houses. The hard problems are dealing with repeated time-varying mechanical stress and dealing with thermal expansion (windows can play fast and loose with this by leaving expansion space around the glass inside the frame).
    - Retric 11y ago
      Crystal silicon not steel, but it's reasonably close to concrete. And concrete is the high end road surface vs. asphalt. Crystal silicon [.6 - 1.3KIc (MPa · m1/2)] https://lirias.kuleuven.be/bitstream/123456789/355152/1/Thermomechanical+properties+and+fracture+in+single+crystal+silicon+-+REVIEWED.pdf https://lirias.kuleuven.be/bitstream/123456789/355152/1/Ther... (Page 12) Concrete [0.2-1.4 KIc (MPa · m1/2)] https://en.wikipedia.org/wiki/Fracture_toughness https://en.wikipedia.org/wiki/Fracture_toughness
deelowe 11y ago
Asphalt is nearly 100% recycled.