Researchers have come up with a new way to store electricity in cement
science.org
science.org
Also, if it's a smart city and big tech is involved, think of the scale of the planned obsolescence issues
Typically the teams you see are being split between several projects and one construction project mnanager is managing several projects.
Then throw in city permitting and inspections which take an awful amount of time and expense.
Is there a reason it's slow? Yes, they're trying to keep budgets low. However there isn't a reason it needs to be slow.
When there's a political will and cultural to do it fast and safely, it gets done. That bridge collapse in Philly on i95 took like 10 days to repair. It also probably cost a lot to repair as well but there was a political will to do it because of how critical that infrastructure is.
Same goes for bridges and highways on California destroyed by earthquakes or landslides. Those get rebuilt quickly but the cost to do so is very high.
There is also real physical limitations when moving dirt around. If you quickly make a big pile it settle quite a bit. So instead you add a few inches at a time and bring out heavy equipment then let it settle, do some tests, and repeat.
Talk about endless construction, see London. Improvements come gradually with new construction, then the old are propped up/covered up/stripped-and-refaced as long as they are useful and upgraded when convenient.
Oxford's wolvercote roundabout took like 3 or 4 years to complete for what could have amounted to a year of work for any American crew.
Want to hear a joke? Skanska workers working.
(It's kind of sad that a publication like Science would mix these up. A road made from cement exclusively would be blown away in a minute. Cement is [just] a binding agent for the aggregate.)
One such quote, although it's throughout the article
> The problem is that cement, a primary ingredient in concrete, is normally a poor electrical conductor. So, in recent years, several groups have made structural supercapacitors by spiking cement with highly conductive forms of carbon, such as graphene or carbon nanotubes. Although these perform well, the ingredients are expensive and hard to produce in the massive volumes used in the cement industry, notes Franz-Josef Ulm, a civil engineer at the Massachusetts Institute of Technology (MIT).
> Ulm and his team mixed a small percent of carbon black with cement powder and added water. The water readily combines with the cement. But because the particles of carbon black repel water, they tend to clump together, forming long interconnected tendrils within the hardening cement that act like a network of wires.
> Ulm and his colleagues cut this wired cement into small plates, creating supercapacitors 1 millimeter thick and 1 centimeter wide, about the size of a button. After adding a membrane, an electrolyte made from potassium chloride—a simple salt—and water, the researchers sealed the sandwich structure. When they then connected a wire to the plates and flipped a switch, cement supercapacitors lit up a series of LED lights.
> To succeed, researchers will need to scale up the button-size plates. Doing that isn’t trivial, Nguyen notes. As supercapacitors get larger their electrical conductivity typically declines, making it harder to inject and extract energy from them. One solution, Ulm notes, is to simply add more carbon black to the mix—but not so much that it weakens the structural integrity of the cement. For structural concrete, the researchers found they could add up to 10% carbon black without compromising too much of its strength. Ulm says the group has patented its technology and is now working to scale it up to match the output of a 12-volt car battery.
They are well aware of the concept of structural integrity and of course the big challenge is scaling up their idea in a way that does not compromise it.
Here's my best idea: You pour regular reinforced concrete in sort of a waffle pattern, make a bunch of capacitor cells in the holes, then put another layer of concrete on top. The individual membranes have limited shear stress. Leaks are isolated. Presumably cells of mostly concrete and water still have pretty good compressive strength, so maybe it will hold together like that. I'm guessing you at least have to increase the total slab thickness, though.
I'm guessing there will be some kind of creative architecture like that before it goes to prod, anyway.
There is a similar system using foam blocks that act as forms and are left in place. Menards sells them (and may own the manufacturer).
"MIT engineers create an energy-storing supercapacitor from ancient materials", 85 comments, https://news.ycombinator.com/item?id=36951089
Where does energy want to flow, to a higher concentration of energy or a lower concentration?
I am more curious what this does to the concrete as it is not uncommon for lightning rods to be grounded to a grounding rod that is in the building's concrete foundation. I think this should be tested prior to mass adoption.
Presumably smart people would be insulating the battery from an external surge like a lightning strike.
However in practical senses the lightning would go into the rest of the ground as the grounding wire would be bypassing the concrete.
And that's just a passive circuit, with an active circuit you have a lot more options.
Note: I studied maths and computing so I could very well be wrong. I would appreciate being set straight by elec eng majors!
Why don't we put springs under massive buildings like skyscrapers that anyway move a little bit with wind?
Maybe the millions of tons compressing the springs a little bit could result in some electricity?
Or under roads and airport tarmac?
For roads, whatever power you generate from the traffic would be less than the additional power those cars require to drive on your road. It would be a net loss. Basically generating electricity from gasoline, with extra steps.
This technology is great, but the real breakthrough will be getting someone like Lennar homebuilders to incorporate this into their constructions by default.
Not yet it's not. There's a world of difference between using samples of concrete "about the size of a button" and scaling up to something the size of the foundation of a house.
And that just gets it to "buildable". To get to "ubiquitous" it also has to be cheap.
Here we go again, SolarRoads…
I know I'm being grumpy and highly skeptical, and that Y combinator is about innovation, but why not make a hackernews to compartmentalize those things?
I would be okay about a paper that discuss feasibility instead of the usual "maybe yes? maybe no." blogspam.
or some random dude (or a tree fall) punctures the wall of your house and sets it on fire