Awesome. Outside of a few strange political situations like HK/Singapore we probably don't actually need to build structures higher than 12-18 stories as well - most examples I can think of are vanity projects.
It strikes me that there might not be a replacement for concrete in other forms of building though - what about dams, bridges, etc?
This is interesting, I didn’t know that desert countries were actually importing sand for construction! Here’s a relatively recent paper looking at the suitability of desert sand to replace the fine aggregate in cement: https://www.sciencedirect.com/science/article/abs/pii/S09500..., concludes that it can be used in small percentages.
Idea: It would be useful to have global competitions with hefty prizes, e.g > $1M, for process inventions that address scarcity problems like this to spur independent young researchers.
In Serbia local mafia is controlling river sand excavations ever since mid-90s, and the most of these sites work completely illegally all this time. Beside the obvious problem of exploiting natural resources, causing erosion of river banks, and destroying the river ecosystem, this also has a much wider negative influence on the society as it's creating a huge chain of corruption of government officials and police. And this is a serious business with a lot of money in the game, to the point that all drug lords there are also in the sand business.
Same in Romania, the local mafia is controlling all the legal and illegal tree cutting with help from the politicians and forest rangers since exporting it to Western countries is lucrative enough to grease the whole chain.
The taxpayers then have to deal with the aftermath of deforestation.
I envision a machine that takes in desert dune sand, arranges four individual grains into a tetrad, and uses concentrated solar light to melt some sand into glass, to bind the tetrads together. Then it ejects the tiny glass-bound pyramid into a collection bin and repeats.
Like a Spacechem/Opus Magnum puzzle that has a dune sand input and a construction sand output.
Sounds cool, but very expensive. Energy spent in essentially building sand. Instead of the current process of just finding it lying around and hauling it to where its needed.
An, no, 'solar light' isn't free. There's a cost in collecting it. And even then, it's worth something as electricity. Probably worth more than the resulting sand is (currently) worth?
Basic mining and minerals is all, entirely and totally about the cost of extraction. It has to pay.
Particle size also matters. Even if your split sand didn't cross the threshold from "sand" to "silt", the coarser sand is still better for construction, IIRC.
One thing I found interesting when visiting the Bahamas is that every few years some entrepreneurial locals pitch the idea of using the sand from the beaches to turn it into glass. Only problem with that: the "sand" is made up of crushed coral and seashells (probably some limestone in there, too), so it's not possible to furnish glass from it.
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[ 2.2 ms ] story [ 70.6 ms ] threadI believe it's available on Prime.
Edit: It seems I am shadow banned. I am going to take this as a deep insult.
Cross-Laminated timber or CLT.
https://en.m.wikipedia.org/wiki/Cross-laminated_timber
12 and 18 storey structures have been built.
As far as fires go, yes, they will burn eventually, but they won’t weaken as quickly as steel. You get more time to evacuate.
It strikes me that there might not be a replacement for concrete in other forms of building though - what about dams, bridges, etc?
https://doi.org/10.1016/j.conbuildmat.2017.08.181
Yeah, wood, too.
https://www.wired.com/2017/05/wood-skyscrapers/
Idea: It would be useful to have global competitions with hefty prizes, e.g > $1M, for process inventions that address scarcity problems like this to spur independent young researchers.
The taxpayers then have to deal with the aftermath of deforestation.
Like a Spacechem/Opus Magnum puzzle that has a dune sand input and a construction sand output.
An, no, 'solar light' isn't free. There's a cost in collecting it. And even then, it's worth something as electricity. Probably worth more than the resulting sand is (currently) worth?
Basic mining and minerals is all, entirely and totally about the cost of extraction. It has to pay.
Alternatively, I wonder if just splitting spherical sand in half would work?
If that ever happens, history does rhyme.
Audio -> https://www.npr.org/sections/money/2018/07/13/628894815/epis...
Transcript -> https://www.npr.org/templates/transcript/transcript.php?stor...