CoRncrete: A corn starch based building material (2017)
research.tudelft.nl
research.tudelft.nl
I initially was skeptical of the utility when I saw the mention of heating requirements, but the temperatures aren’t that extreme, and seem very reasonably achieved with electrified energy sources (which in turn can easily be supplied via renewables).
Being able to produce concrete without the emissions involved with the production of portland cement is a major goal of decarbonizing the building stock, so it’s always good to see new lines of research in this front, even if still in the germinal stages!
ARPA-E Hestia has some cool alternatives (a bit further along in research stages) for those interested:
AFAICT, cornstarch has a similar emissions to portland cement:
https://apps.carboncloud.com/climatehub/product-reports/id/7...
Point still stands - it’s a major goal of building technology to mitigate the embodied carbon of buildings due to concrete.
There are more promising bio-materials for construction.
Attempts have been made to make boards from bagasse, the leftover fiber from sugar cane processing. It works, more or less. The most useful application for bagasse is making clamshell containers and plates for fast food. It's cheap, biodegradable, and non-toxic.
It’s also a major time saver since unlike concrete it doesn’t need to set, and the products are basically manufactured panels that don’t need specialized workers to install.
By 1964, not much of the colonnade was still standing. This was all that was left.[1] What you see today is a full rebuild.
[1] https://www.sfgate.com/bayarea/article/Dramatic-Palace-of-Fi...
Would be interesting if transient infrastructure and time-limited laws would lead to a more beneficial way of living.
There are many modern buildings that are built the same way as other modern cities and designed to last.
They have very modern infrastructure, and while what you're describing does exist, but is by no means the norm nowadays.
For example old roadside motels from the '50s and '60s could easily be remade into dorm style apartments with micro kitchens supplemented by communal bathrooms, but laws, especially hygiene and fire codes, currently prevent that. Those motels are built of sturdier materials than many modern homes, and only need to be refitted with fire suppression systems and heat pumps to be cheap housing.
Making temporary housing is just creating a new problem rather than solving an existing one.
But what if they disappeared entirely and we built something new in its place? What if the entire block was completely transformed at some point?
I remember a celebration in the late 1980s for a retiring British architect/art historian, who reminisced about being an architecture student during the Blitz in London. While he and his pals sheltered underground during the bombing, they shared a (slightly shameful) excitement about the prospect of rebuilding London with "something new" after the war was over.
In contrast to some European cities, where the goal was to recreate as much of the pre-war architecture as possible, postwar London was, as I understand it, rebuilt with lots of new architecture. My impression is that most people think a lot of it was pretty terrible.
I can empathize with modern attempts at buildings looking ugly and soulless. But I feel that’s part of the point of transience - the next generation can rebuild it in their style. It’s also the problem with how every city becomes overpacked and unlivable when things change, as nothing is future proof.
We shouldn’t continually impose our choices (architectural, zoning, location) on all subsequent generations.
As for building something new... What exactly would need to be new to justify the construction? Density in cities only continues to grow, but that density is solved by verticality rather than replacement. You build up and you build onto rather than build out and build over. If it's to replace architectural styles, that is something that has to be decided on an individual example, as there's things like a city's aesthetic identity, historical significance, and architectural cohesion to consider. Erasing Lancashire's infamous council houses would be decried for decades despite their homogeneity and and connections with poverty, but getting rid of the giant monobloc apartments in Sheffield likely wouldn't be opposed too much because Brutalism's never much been liked and there's plenty of examples.
I was philosophizing more about changing the way we enforce permanency of decisions taken by humans who lived before on everyone who comes after them.
The compressive strength of cornstarch concrete maxes out at 26 MPa according to the paper, while different Portland cement formulations range from 20-50 MPa, and epoxy-polymer can go up to > 100 MPa, though brittleness is a problem.
The optimal strategy for cleaning up Portland cement production is probably (1) renewable-based electrification of the kilns used to make CaO from CaCO3 (limestone), and (2) capture and stabilization of the CO2 from the kilns in a form like carbon fiber or diamond. Still a bit sci-fi but technologically feasible (but not economical at present).
https://apps.carboncloud.com/climatehub/product-reports/id/7....
Not sure I understand how, since regular concrete made from portland cement does require heating to cure - in fact it's exothermic.
The vast majority of the emissions from traditional concrete come from the manufacturing of portland cement. It's not clear how a renewable grid would significantly lower the emissions of producing cornstarch, since the majority of emissions happen at the agricultural stage, via the petroleum based fertilizers.
"regular concrete made from portland cement doesn't require heating to cure"
It's more "sand based" than "corn based".
While this certainly isn't great for most obvious building use-cases, I wonder if it would have utility for ex. building a research base on the moon someday.
I think the main challenge with your idea is that you have to get the corn starch to the moon… you really want your solution to be focused on ISRU (in-situ research utilization) as much as possible.
I think you'll find that transporting the water is far more costly, which would be the case with any lunar concrete
I don't think I have access to the full paper, but it is described as biodegradable, which seems to be the opposite of what you'd want your house to be made of?
- Global production of corn: 1.2 gigatonnes, source https://ipad.fas.usda.gov/cropexplorer/cropview/commodityVie...
- Global production of Portland cement: 4.1 gigatonnes, source https://gccassociation.org/key-facts/
And of course, cornstarch is only about 70% of the weight of corn. IIRC grain production statistics are usually by dry weight, but if we assume wet weight, it's even worse. Even if we completely obliterated the meat and biofuel industries worldwide, we would struggle to meet a quarter of the current demand for cement, which anyway is forecast to increase.
This just seems like another fake-green boondoggle, similar to ethanol.
25 mpa concrete is "i'm doing my driveway" concrete or "I bought a bag at home depot" concrete not high strength concrete.
Recalling when, after years of hype, the demand for corn-based ethanol as a fuel competed with corn for food, leading to even greater food insecurity world-wide.
Grifter's gotta grift, but that doesn't mean their BS gets to go unchallenged.
Cool research, but I'll pass on using it.
https://news.ycombinator.com/item?id=41751122
Therefore even research results that do not seem useful in normal conditions may find some circumstances where their use becomes preferable.
some more discussion on this here: https://en.wikipedia.org/wiki/Agricultural_policy_of_the_Uni...
https://smartcitysweden.com/focus-areas/mobility/biofuels/
But the numbers don’t add up. Instead, it looks like they’re simply burning less gas (biofuels or not):
"It is important to note that biofuel production and consumption, in and of itself, will not reduce GHG or conventional pollutant emissions, lessen petroleum imports, or alleviate pressure on exhaustible resources."
I.e., what the government claims it to be.
Hence my sarcastic comment about trusting the government and its "experts".
https://www.energy.gov/articles/biofuels-greenhouse-gas-emis...
Out in the country is the only place I can still find 100% gasoline.
But mandating a certain percentage of ethanol ensures a minimum level of demand, preventing that problem.
I think there is some kind of presupposition here about how voting correlates to policy as enacted. What I would put forward instead is that regardless of how rural people vote, it's Big Ag lobbying and setting the agenda/policy.
If I want to sell you raw milk from a cow on my pasture it can only be for non-human consumption. If I want to sell you beef you either have to buy 1/4 or more of the animal before its processed or I have to load it onto a trailer and allow a state or USDA facility process it, leaving me with lovely packaged cuts that have a high level of stress hormones and was sprayed down with bleach.
I want more of this kind of thing, not less. Politicians should be scared to piss lots of different voting blocs off. The way we do democracy is terrible at rewarding politicians for enacting (roughly) the will of the people.
Or big agribusiness and their campaign donations?
Cars don’t need ethanol. In fact they don’t like it. It causes problems for older cars, the auto industry had to adjust things to be able to survive a certain percent ethanol without damage.
Yes, I know there's plenty of better land, but comparing the scale needed to something we've already got likely helps change people's minds about the practicality of PV.
They're a bad fit in practice on basically every count, but the idea was interesting enough to pass the elevator pitch sniff test. Ruggidised PV as footpaths might not even suck, though I suspect even then they'd be better as roofing over footpaths rather underfoot.
Or it can go by the wayside. Both outcomes are fine. But no need to pre-emptively dismiss something that is obviously not being pitched as a production-ready building material…
Fixing waste and distribution would more than make up for it, and that’s not including the possibility of shifting corn over from ethanol instead if this proves actually useful.
"Seed Oil converts to PLASTIC"
https://www.youtube.com/watch?v=Ra_tCL5-4c0&t=1s
And earlier listened to Robert Kennedy on a podcast where he discussed how offshore wind farms, have turbines placed in the ocean with giant blades that can explode and pollute water with shards that close beaches and kill Whales. While significantly more expensive than terrestrial wind farms.
Public opinion is often swayed by such labels like "environmentally friendly", "reusable", "pro environment". Who could not support such things ... Turns out environmentally friendly products, often are just a swindle to get massive amount of subsidy money from government ... for bad ideas. It's a form of corruption, as politicians that approve these things often benefit in some way. While public loses.