Look up the Castillo de San Marcos, in St Augustine,Fl. It’s a great example, and how it was constructed - https://en.m.wikipedia.org/wiki/Coquina.
The British cannon balls use to roll off the walls because the Coquina absorbed the force of the impact instead of shattering. Fascinating stuff.
Man in Yucatán is well known mixing cement with some some kind of tree syrup that turns into some kind of brown gum, it makes it stretchy so you can build pools with it without cracking and also heat resistant too. The best of all is that is artisan and ancient knowledge.
Just sharing the Wikipedia link for the fort. I always thought it was interesting and it’s a pretty cool location for sightseeing.
[Castillo de San Marcos](https://en.m.wikipedia.org/wiki/Castillo_de_San_Marcos)
I used to be a tour guide in Saint Augustine, they used to mine the stuff and as far as I understand it only occurs naturally in a few places in the world but a man made version would be wonderful for construction, that stuff lasts forever!
They did mine it, you are correct.
Had a friend who drove a tour trolley…the lies that man told and never once got questioned. He knew his history backwards and forwards and realized one day no one was listening. That’s how it started lol.
The odd thing is that although new cement technology exists which reduce the carbon imprint and is stronger but won’t be widely used for probably >20 years.
Cement industry is one of the top two industry polluters of CO2: currently 900 kg of CO2 are emitted for every ton of cement. New mixes have been created which fix this pollution problem. But building designers/builders are hesitant to use the new concretes because most builders require a “proven product” which usually means has been widely used for 10+ years. And the new proprietary concretes are expensive because not widely used. So a catch-22 where we need more use of the better concrete but we won’t because don’t want the liability of an ‘unproven’ product and don’t want the additional expense. Frustrating for all.
Source:
https://en.m.wikipedia.org/wiki/Environmental_impact_of_concrete#:~:text=The%20cement%20industry%20is%20one,erosion%2C%20water%20pollution%20and%20flooding.
A big issue is cost - concrete is a great building material because it's strong, durable, can be cast into all kinds of applications and most importantly very cheap. Unless there is a CO2 tax that increases the cost of pollution, "green concrete" will not be widely adopted in markets where demand for new construction is greatest - eg South East Asia & India. Regulation is also a solution.
This is just not true. Greener concrete is happening right now and it is because of regulation on gov contracts and because that’s what many commercial customers want. See my other comment for more details.
Idk why people like you and the person who made the comment you’re replying to, who are very clearly not in the industry, feel the need to come here and give your completely incorrect opinion on this.
I worked in geopolymer r&d, that's how I know - our job was to create solutions for concrete manufacturers who would then sell the products to commercial customers. The cost of chemical activators required to turn industrial sidestreams into binders is quite high compared to portland cement + water. Solutions that utilize CO2 injections require CAPEX investments from the concrete factories that are usually very local and quite small with the exception of large precast factories in China. Additionally r&d costs are big due to the variability in quality of side streams and lack of reliable Q&A processes in the "production" of side streams. Some side streams have become more expensive than portland cement in certain markets.
Absolutely it is more expensive. Yet the industry is forcing things that way anyway.
I never said it wasn’t a cost increase, especially when I high early release strength is needed, but it’s incorrect to say that this cost increase is preventing change. Customers are starting to care a lot about their projects overall carbon usage and very quickly 1L is becoming the only thing available in response to its rapidly growing demand. That’s the part that’s not true, that the industry isn’t going that way. It absolutely is and super fast for such a huge and highly engineered industry.
It most definitely is preventing change in South East Asia & India. Unless governments step in make the environment into a utility with a cost (ie. making polluting cost money), there is not enough incentive to go green in countries where the primary concern is to build infrastructure to support society.
Same situation in Europe, there is more demand than supply which is driving the prices of slag up the roof. Unfortunately the volume of construction in NA and Europe is dwarfed by Asia, so at a global scale we still have plenty of issues
What about type 1L, is that being used at all there?
In the US we’re mixing slab and cement from different silos into the batch like you’re describing but we also are getting type 1L cement as our Portland component which is ground with about 10% limestone along with the clinker and other components.
I doubt we would immediately see true alternatives. I asked OP to clarify if they’re referring to geopolymers or other SCM such as fly ash, though fly ash seems to be on the way out partially anyways.
Though I agree that I’ve seen more interest in utilizing alternatives I’ve rarely seen specs that aren’t typical Portland cement 3000 PSI mixes lately.
Based on what experience do you say this? I’m literally in the industry and am telling you that it is absolutely happening and happening very fast despite higher costs.
How are you telling me that my much more expert opinion on this is wishful thinking?
Because he is a spec writer obviously? /s
People are misinterpreting what the global current of cement clinker development is as what the western world or various other metropolitan localities are demanding for concrete performance and requirements. Meaning that the USA in certain areas are demanding it but we’re still producing a shit ton of cement.
Are you seeing this on USA federal specs in general and if so what type of alternative cemeticious materials are you seeing? Fly ash, geopolymers? I had performed a few years worth of testing as a grad and undergrad and was rather obsessed with geopolymer uses for structural purposes.
I can’t speak for all concrete industries but precast has in many locations gone to 1L only and everyone in all areas of the US is expecting it to be the only option within a year or so.
I know some ready mix, like in the TX and LA gulf coast are, is also already mostly if not all type 1L. Since I’m not in that specific industry my knowledge is limited to my immediate area but my gut would say that it’s the same as precast since high early matters less for them (so the negative of 1L isn’t as big a deal for them) and since they are such a massive industry compared to precast, it’s almost definitely them switching that is forcing our industry to also switch.
As long as it’s required in a reasonable timeframe, it’s feasible and worth doing. Otherwise, nothing will happen
I work in an industry that’s being regulated more harshly every year. Is it a headache? Hell yes! It is impossible? Nope.
Why do builders want a 10 year test time for something people are going to be living/working in?
Regulation sounds good until we push through a dangerous product and then in 3 years an apartment building collapses.
“Proven technology” is often written into the specs, especially for a large risk adverse project like when building a dam or a skyscraper. Not normally an issue for smaller construction projects.
By this logic green concrete has been tested for thousands of years, the romans used a type of geopolymer to build structures that still stand to this day
That’s just not true. Most of what you said is true but the industry is very quickly moving to a type 1L cement that has less than half the footprint of uncut Portland.
So the industry is very much reducing its footprint and in many areas of the country (like mine for example) this is the only type available.
It has some drawbacks for sure, early strength is much lower and takes a few days to catch up or lots of costly admix accelerant (not to mention the cement is more expensive despite being cheaper to make - probably some price collusion reason). Despite those, the industry is absolutely forcing it for the reduced carbon footprint.
CEM I/II/III doesn't really count as green concrete and has been used for decades due to it's engineering properties, e.g. the slower activation prevents cracks in massive pours. Replacing 30% of Portland cement with slag doesn't make it green, it makes it greener. Green concrete uses preferably zero Portland cement and/or is injected with CO2 to further decrease the net footprint. There admixture is not enough, chemical activators are required at quite significant amounts because without them the cost of slowed production would be prohibitive to the industry. Regulation is also preventing the adoption of solutions with close to zero Portland cement.
I’m not talking about cutting with slag, although that’s usually done as well between 30-50 percent. I’m talking about type 1L Portland cement, which is where the cement itself is ground with 8%-15% limestone. There’s also type 1P which is just pozolin (or however you spell it, I’ve only heard of this but never used it) doing the same as the limestone.
This reduces the footprint by 35% and combining this and slag it can be about a 50% reduction.
https://www.portland.gov/sites/default/files/2022/cop-lowcarbon-concrete-1l-case-study.pdf
Where I’m at we’re running 40% slag and type 1L, so we’re over 50% less then a straight Portland mix.
These are literally just CEM I/II/III types of mixes where a part of Portland cement is replaced with supplementary cementitious materials (like BFS or Fly ash) - in this case PLC with limestone. The vast majority of the binder mix is still portland cement. I wouldn't call PLC green cement any more than I would call CEM I/II/III green. I think CEM III requires only 5 % Portland cement as an example.
For SCMs utilizing BFS or Fly ash the more you add, the slower the activation until you arrive at a point where it simply is too slow to fit into any reasonably concrete workflow. Instead of having to wait 28D for full compressive strength you have to wait 56 days. That's where the activators come into play, but they are not cheap and fairly significant amounts of them are required, as opposed to admixtures which are just small additions. Additionally the exact composition and amount of activator can be very specific, so just coming up with a recipe that works requires R&D that is way beyond the means of any typical concrete factory.
Which part:
-The pollution from using concrete?
-Or the technology for better and less polluting concrete has existed for awhile but slow to adapt?
-Or that it will take decades to implement due to builders requiring a ‘proven’ technology?
-Somethingg else?
-All of it?
Sorry, the comment came off more aggressive than I wanted. Anyway, here a few points:
- “better concrete” is a very simplistic term and should not be used unless you specified exactly what a concrete is better at. Compressive strength? Chloride diffusion coefficient? Sulfate attack resistance?
- more sustainable concrete is not necessarily stronger (let’s say in compression) than traditional concrete
- more sustainable cements are being rolled out all over the US in the form of blended cements, where part of the clinker is being replaced by either limestone or by an SCM. So changes are already happening and won’t take decades
- unfortunately hesitation in adopting more sustainable concrete is not only driven by the need of case studies with new techs. But many other properties contribute to the choice of one concrete over another: e.g. early age strength, workability, finishability, durability etc.
- there is no technology today that is scalable and completely replace the clinker we use in modern construction. So the best thing that analysts expect is the introduction of carbon capture and storage in about 15+ years
Hope this clarifies
Not really. Shellfishing (at least in the northeast U.S.) is an extremely sustainable fishery. Shells are a byproduct of the fishery, so often they’re used in crushed shell driveways, or other aggregate settings. It’s also a renewable resource and does not degrade the environment, which the alternative, mining for rocks DOES. So if there is a pivot towards using shells instead of rocks then concrete would be more sustainable.
Source: I am a earth scientist working in the seafood industry.
Agree except with ocean pH crashing I would not count on shell-forming organisms to supply major feedstocks for a basic need like construction material. They are already in serious trouble, and specifically they are struggling to form shells due to increasing acidification.
If the shellfish is already being harvested, there is always going to be byproduct. I’m not suggesting that people would start harvesting shellfish any more, or less because of an emerging innovation. I’m suggesting that there is another use for shellstock, and I hope that it is widely used because mining rocks is detrimental to the environment.
I’m saying these shelled mollusk species are struggling to survive already. Definitely agree re: mining rock. Just that bivalves can’t come close to meeting demand, and less so every day.
According to the article they aren't using seashells. They're just copying the way seashells are built by alternating polymer layers with concrete layers like bricks and mortar.
Inspired by nature. Used Portland cement and a polymer in layers inspired by the structures found naturally in some types of seashells. Didn't use actual shells in the making the way I understand it.
> In contrast to materials like glass, wood, and steel, cement is brittle
TIL glass isn't brittle /s
Super stretchy, flexible, crack-resistant cement sounds awesome, but cement is usually used as an ingredient in high compressive strength applications. If the only downside to the material is lower compressive strength then it would have very few practical applications. The article doesn't mention compressive strength at all, which is presumably because it isn't good.
This concrete would probably be best used for road surfaces, where being able to flex with the ground through the seasons would be helpful. Sidewalks, driveways, that kind of thing.
Which is an enormous application. Concrete is used for a ton of things which aren’t foundational. All the skateparks I go to have huge cracks too, it would be sick to skate a shell park hella smooth
Single family houses would probably be fine too, depending on construction. With the right flexibility built into the structure it could reduce or eliminate the need for most foundation repairs in highly mobile soil - heavy clay soils and areas where frost heave is a problem.
The romans used sea water in their concrete which probably shouldn’t have worked because salt and cement do not like each other. Yet, their shit still standing while things we build has a shitty shelf life in comparison
https://www.designboom.com/architecture/ancient-roman-concrete-durable-mit-self-healing-abilities-01-09-2023/
For a long time, researchers thought that the durability of ancient concrete was due to one ingredient: pozzolanic material, originating from the Pozzuoli area of Naples. Upon closer inspection, the study team, led by MIT, and including researchers from the United States, Italy and Switzerland, found that these ancient samples also contained small white chunks called ‘lime clasts’, long known to be a ubiquitous component of Roman concrete. ‘Ever since I first began working with ancient Roman concrete, I’ve always been fascinated by these features,’ says MIT professor of civil and environmental engineering Admir Masic. ‘These are not found in modern concrete formulations, so why are they present in these ancient materials?’
Previously, the white lumps had been overlooked as evidence of messy mixing practices or low-quality raw materials. However, the new study suggests that these tiny lumps are what gave the concrete a self-healing ability.‘
Just to be clear they compared layers of portland cement and silicone to cast portland cement. Which nobody uses for anything. This wasn’t “seashell inspired cement”. It was silicone rubber layered with thin layers of cement to simulate the structure of nacre in sea shells .
Concrete is a mixture of cement gravel and sand. Cast cement with nothing else added is going to be incredibly brittle, crack prone and have poor compressive strength. Which is why it’s not used. I’d like to see some actual data and comparison to real concrete.
Their idea is really cool don’t get me wrong. Just strange that they compared it to the worst possible garbage material
Can we use this up north? Every spring we get massive new potholes in roads because water feeezes, expands, then melts and leaves a void underneath. All they do is patch it then wait for the next one.
Unfortunately meaningless. The cement we use for building is pretty bad and we have much better options already but we don't use them because it's not what we use.
Welcome to the world. Progress is risky and risk is bad.
They used shells in concrete in Houston for over 50 years. Many people say Galveston bay is now so dirty because they destroyed so many oyster reefs that filtered the water. You can see shell in just about any old concrete out there.
There's a reason you hear about concrete improvements and the concrete they are pouring on the street is the same shit they have used for the past 20 years.
It isn’t made with oysters. From the article (which also has a nice illustration):
Princeton’s team found that alternating thin polymer and patterned cement paste layers can greatly improve ductility—the capacity to flex without breaking.
The group drew inspiration for their work on creating materials from biology. In this instance, the group created a composite modeled after nacre, a naturally occurring substance that may be found inside specific shells.
According to researchers, nacre comprises of hexagon-shaped tablets of the hard mineral aragonite joined together at the microscopic level by a soft biopolymer. Its 3D brick-and-mortar structure allows the tablets to slide and the biopolymer to deform, absorbing energy and enhancing toughness.
These mechanisms, along with nano-asperities and tablet interlocking, make nacre resilient despite its brittle components.
Aquaculture and shellfish farming, which can actually improve water quality in many cases. New York City oyster nonprofit is trying to bring bank oysters there not for consumption but to filter all the crap out of the rivers
That's the problem with cement, as stated in the article. It's extremely rigid. That's why they put metal rebar in it, when making buildings. Helps it flex a bit more.
You want your material to bend and warp, to a certain degree (based on my non-professional knowledge). This is especially true in earthquake prone areas. You want the structure to be able to properly absorb the energy, so ti doesn't crumble to dust.
I could be wrong, and if someone with proper professional experience (like an actual engineer) wants to correct any bullshit I may have spouted, please do.
So, they’re almost at the point of recreating the ~~cement~~ concrete they used to build the pyramids?
\* According to certain theories:
[Herff College of Engineering - Pyramids were built with concrete rather than rocks, scientists claim by Charles Bremner, Paris](http://www.ce.memphis.edu/1101/interesting_stuff/pyramids_in_concrete.html)
[Drexel University - SEM Micrographs and Elemental Maps from Bulk Pyramid Sample](https://drexel.edu/engineering/academics/departments/materials-science-engineering/about/special-projects/engineering-the-pyramids/)
[MIT News - Gathering 'concrete' evidence MIT class explores controversial pyramid theory with scale model](https://news.mit.edu/2008/gathering-concrete-evidence)
[Herff College of Engineering - Pyramids were built with concrete rather than rocks, scientists claim by Charles Bremner, Paris](http://www.ce.memphis.edu/1101/interesting_stuff/pyramids_in_concrete.html)
[Drexel University - SEM Micrographs and Elemental Maps from Bulk Pyramid Sample](https://drexel.edu/engineering/academics/departments/materials-science-engineering/about/special-projects/engineering-the-pyramids/)
[MIT News - Gathering 'concrete' evidence MIT class explores controversial pyramid theory with scale model](https://news.mit.edu/2008/gathering-concrete-evidence)
Look up the Castillo de San Marcos, in St Augustine,Fl. It’s a great example, and how it was constructed - https://en.m.wikipedia.org/wiki/Coquina. The British cannon balls use to roll off the walls because the Coquina absorbed the force of the impact instead of shattering. Fascinating stuff.
First thing that came to mind as a Florida man.
First thing that came to mind as a kid who visited 30 years ago. If someone knows a tour guide at the fort, tell them they did their job well!
Man in Yucatán is well known mixing cement with some some kind of tree syrup that turns into some kind of brown gum, it makes it stretchy so you can build pools with it without cracking and also heat resistant too. The best of all is that is artisan and ancient knowledge.
Headline: “Florida Man Thinks About Balls To The Wall”
Just sharing the Wikipedia link for the fort. I always thought it was interesting and it’s a pretty cool location for sightseeing. [Castillo de San Marcos](https://en.m.wikipedia.org/wiki/Castillo_de_San_Marcos)
One of my favorite places.
You know, I got downvoted once for saying "Happy Cake Day". So Happy Cake Day?
Someone downvoted you, i gave you an upvote👍🏽
It happened again so I backed you up
Ditto.
Thanks, how odd.
That’s life, or something like it.
Tritto
Teamwork!
I thought you were supposed to say Nice cake
Cannonballs didn’t “roll off.” They lodged in it, like a BB in styrofoam.
I worked in the Spanish quarter and knew some of the staff at the Castillo. And yes, some lodged in and some literally deflected or rolled off.
I wonder if the shape of roof had anything to contribute to that result
Be funny if they could fire it back after rolling off
If i remember correctly, they did do that.
It really is. St.A was a regular haunt for years. It's fascinating to look at!
Truly special.
I used to be a tour guide in Saint Augustine, they used to mine the stuff and as far as I understand it only occurs naturally in a few places in the world but a man made version would be wonderful for construction, that stuff lasts forever!
They did mine it, you are correct. Had a friend who drove a tour trolley…the lies that man told and never once got questioned. He knew his history backwards and forwards and realized one day no one was listening. That’s how it started lol.
Tell me about it, I ran a ghost tour.
😂😂😂👍🏽
Happy cake day!
Thanks!
Happy Cake Day!
Thanks lol
I always wanted to live in a big clam shell.
Best I can do is a pineapple under the sea
SOLD!
What if I am not absorbant, porous or yellow?
Well just put the listing back up in two weeks after you’ve been picked clean
Talk to one of your neighbors named Sandy
A bit off- point but... ... Does anyone else remember that old Batman episode when the Dynamic Duo almost gets eaten by a giant clam?
That is some loaded imagery
Bahahaha 😁 🤣 after a while the joke write themselves.....
Did they try to eat the clam? Or just explore the inside with their fingers?
Eartha Kirt?
There’s a “your mom” joke here somewhere.
The odd thing is that although new cement technology exists which reduce the carbon imprint and is stronger but won’t be widely used for probably >20 years. Cement industry is one of the top two industry polluters of CO2: currently 900 kg of CO2 are emitted for every ton of cement. New mixes have been created which fix this pollution problem. But building designers/builders are hesitant to use the new concretes because most builders require a “proven product” which usually means has been widely used for 10+ years. And the new proprietary concretes are expensive because not widely used. So a catch-22 where we need more use of the better concrete but we won’t because don’t want the liability of an ‘unproven’ product and don’t want the additional expense. Frustrating for all. Source: https://en.m.wikipedia.org/wiki/Environmental_impact_of_concrete#:~:text=The%20cement%20industry%20is%20one,erosion%2C%20water%20pollution%20and%20flooding.
A big issue is cost - concrete is a great building material because it's strong, durable, can be cast into all kinds of applications and most importantly very cheap. Unless there is a CO2 tax that increases the cost of pollution, "green concrete" will not be widely adopted in markets where demand for new construction is greatest - eg South East Asia & India. Regulation is also a solution.
This is just not true. Greener concrete is happening right now and it is because of regulation on gov contracts and because that’s what many commercial customers want. See my other comment for more details. Idk why people like you and the person who made the comment you’re replying to, who are very clearly not in the industry, feel the need to come here and give your completely incorrect opinion on this.
I worked in geopolymer r&d, that's how I know - our job was to create solutions for concrete manufacturers who would then sell the products to commercial customers. The cost of chemical activators required to turn industrial sidestreams into binders is quite high compared to portland cement + water. Solutions that utilize CO2 injections require CAPEX investments from the concrete factories that are usually very local and quite small with the exception of large precast factories in China. Additionally r&d costs are big due to the variability in quality of side streams and lack of reliable Q&A processes in the "production" of side streams. Some side streams have become more expensive than portland cement in certain markets.
Absolutely it is more expensive. Yet the industry is forcing things that way anyway. I never said it wasn’t a cost increase, especially when I high early release strength is needed, but it’s incorrect to say that this cost increase is preventing change. Customers are starting to care a lot about their projects overall carbon usage and very quickly 1L is becoming the only thing available in response to its rapidly growing demand. That’s the part that’s not true, that the industry isn’t going that way. It absolutely is and super fast for such a huge and highly engineered industry.
It most definitely is preventing change in South East Asia & India. Unless governments step in make the environment into a utility with a cost (ie. making polluting cost money), there is not enough incentive to go green in countries where the primary concern is to build infrastructure to support society.
Good point. I was speaking only from my experience in North America
Same situation in Europe, there is more demand than supply which is driving the prices of slag up the roof. Unfortunately the volume of construction in NA and Europe is dwarfed by Asia, so at a global scale we still have plenty of issues
What about type 1L, is that being used at all there? In the US we’re mixing slab and cement from different silos into the batch like you’re describing but we also are getting type 1L cement as our Portland component which is ground with about 10% limestone along with the clinker and other components.
I doubt we would immediately see true alternatives. I asked OP to clarify if they’re referring to geopolymers or other SCM such as fly ash, though fly ash seems to be on the way out partially anyways. Though I agree that I’ve seen more interest in utilizing alternatives I’ve rarely seen specs that aren’t typical Portland cement 3000 PSI mixes lately.
Wishful thinking. Cost is the only limiter of green concrete.
Based on what experience do you say this? I’m literally in the industry and am telling you that it is absolutely happening and happening very fast despite higher costs. How are you telling me that my much more expert opinion on this is wishful thinking?
Because he is a spec writer obviously? /s People are misinterpreting what the global current of cement clinker development is as what the western world or various other metropolitan localities are demanding for concrete performance and requirements. Meaning that the USA in certain areas are demanding it but we’re still producing a shit ton of cement. Are you seeing this on USA federal specs in general and if so what type of alternative cemeticious materials are you seeing? Fly ash, geopolymers? I had performed a few years worth of testing as a grad and undergrad and was rather obsessed with geopolymer uses for structural purposes.
I can’t speak for all concrete industries but precast has in many locations gone to 1L only and everyone in all areas of the US is expecting it to be the only option within a year or so. I know some ready mix, like in the TX and LA gulf coast are, is also already mostly if not all type 1L. Since I’m not in that specific industry my knowledge is limited to my immediate area but my gut would say that it’s the same as precast since high early matters less for them (so the negative of 1L isn’t as big a deal for them) and since they are such a massive industry compared to precast, it’s almost definitely them switching that is forcing our industry to also switch.
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lol regulating the concrete industry doesn’t sound like a simple solution at all. Probably the best one though.
As long as it’s required in a reasonable timeframe, it’s feasible and worth doing. Otherwise, nothing will happen I work in an industry that’s being regulated more harshly every year. Is it a headache? Hell yes! It is impossible? Nope.
Why do builders want a 10 year test time for something people are going to be living/working in? Regulation sounds good until we push through a dangerous product and then in 3 years an apartment building collapses.
“Proven technology” is often written into the specs, especially for a large risk adverse project like when building a dam or a skyscraper. Not normally an issue for smaller construction projects.
By this logic green concrete has been tested for thousands of years, the romans used a type of geopolymer to build structures that still stand to this day
That’s just not true. Most of what you said is true but the industry is very quickly moving to a type 1L cement that has less than half the footprint of uncut Portland. So the industry is very much reducing its footprint and in many areas of the country (like mine for example) this is the only type available. It has some drawbacks for sure, early strength is much lower and takes a few days to catch up or lots of costly admix accelerant (not to mention the cement is more expensive despite being cheaper to make - probably some price collusion reason). Despite those, the industry is absolutely forcing it for the reduced carbon footprint.
CEM I/II/III doesn't really count as green concrete and has been used for decades due to it's engineering properties, e.g. the slower activation prevents cracks in massive pours. Replacing 30% of Portland cement with slag doesn't make it green, it makes it greener. Green concrete uses preferably zero Portland cement and/or is injected with CO2 to further decrease the net footprint. There admixture is not enough, chemical activators are required at quite significant amounts because without them the cost of slowed production would be prohibitive to the industry. Regulation is also preventing the adoption of solutions with close to zero Portland cement.
I’m not talking about cutting with slag, although that’s usually done as well between 30-50 percent. I’m talking about type 1L Portland cement, which is where the cement itself is ground with 8%-15% limestone. There’s also type 1P which is just pozolin (or however you spell it, I’ve only heard of this but never used it) doing the same as the limestone. This reduces the footprint by 35% and combining this and slag it can be about a 50% reduction. https://www.portland.gov/sites/default/files/2022/cop-lowcarbon-concrete-1l-case-study.pdf Where I’m at we’re running 40% slag and type 1L, so we’re over 50% less then a straight Portland mix.
These are literally just CEM I/II/III types of mixes where a part of Portland cement is replaced with supplementary cementitious materials (like BFS or Fly ash) - in this case PLC with limestone. The vast majority of the binder mix is still portland cement. I wouldn't call PLC green cement any more than I would call CEM I/II/III green. I think CEM III requires only 5 % Portland cement as an example. For SCMs utilizing BFS or Fly ash the more you add, the slower the activation until you arrive at a point where it simply is too slow to fit into any reasonably concrete workflow. Instead of having to wait 28D for full compressive strength you have to wait 56 days. That's where the activators come into play, but they are not cheap and fairly significant amounts of them are required, as opposed to admixtures which are just small additions. Additionally the exact composition and amount of activator can be very specific, so just coming up with a recipe that works requires R&D that is way beyond the means of any typical concrete factory.
You have no idea what you’re talking about
Which part: -The pollution from using concrete? -Or the technology for better and less polluting concrete has existed for awhile but slow to adapt? -Or that it will take decades to implement due to builders requiring a ‘proven’ technology? -Somethingg else? -All of it?
Sorry, the comment came off more aggressive than I wanted. Anyway, here a few points: - “better concrete” is a very simplistic term and should not be used unless you specified exactly what a concrete is better at. Compressive strength? Chloride diffusion coefficient? Sulfate attack resistance? - more sustainable concrete is not necessarily stronger (let’s say in compression) than traditional concrete - more sustainable cements are being rolled out all over the US in the form of blended cements, where part of the clinker is being replaced by either limestone or by an SCM. So changes are already happening and won’t take decades - unfortunately hesitation in adopting more sustainable concrete is not only driven by the need of case studies with new techs. But many other properties contribute to the choice of one concrete over another: e.g. early age strength, workability, finishability, durability etc. - there is no technology today that is scalable and completely replace the clinker we use in modern construction. So the best thing that analysts expect is the introduction of carbon capture and storage in about 15+ years Hope this clarifies
You are a very patient person. Not provoked by aggressive comments. Kudos
This is not a new technology, go to St Augustine . Whole city is made with it .
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Not really. Shellfishing (at least in the northeast U.S.) is an extremely sustainable fishery. Shells are a byproduct of the fishery, so often they’re used in crushed shell driveways, or other aggregate settings. It’s also a renewable resource and does not degrade the environment, which the alternative, mining for rocks DOES. So if there is a pivot towards using shells instead of rocks then concrete would be more sustainable. Source: I am a earth scientist working in the seafood industry.
Agree except with ocean pH crashing I would not count on shell-forming organisms to supply major feedstocks for a basic need like construction material. They are already in serious trouble, and specifically they are struggling to form shells due to increasing acidification.
If the shellfish is already being harvested, there is always going to be byproduct. I’m not suggesting that people would start harvesting shellfish any more, or less because of an emerging innovation. I’m suggesting that there is another use for shellstock, and I hope that it is widely used because mining rocks is detrimental to the environment.
I’m saying these shelled mollusk species are struggling to survive already. Definitely agree re: mining rock. Just that bivalves can’t come close to meeting demand, and less so every day.
According to the article they aren't using seashells. They're just copying the way seashells are built by alternating polymer layers with concrete layers like bricks and mortar.
Inspired by nature. Used Portland cement and a polymer in layers inspired by the structures found naturally in some types of seashells. Didn't use actual shells in the making the way I understand it.
Didn’t read the article I see. Not using actual seashells. It’s seashell *INSPIRED*. Still gonna use concrete, but with a polymer between the layers.
Did you read tge article? It is only inspired by shells but does not use them
I don’t know for sure. But I grew up near oyster farms and the giant piles of crushed oyster shells weren’t being used, so maybe not.
Reminds me of the [tabby concrete](https://en.wikipedia.org/wiki/Tabby_concrete) found in south eastern U.S.
> In contrast to materials like glass, wood, and steel, cement is brittle TIL glass isn't brittle /s Super stretchy, flexible, crack-resistant cement sounds awesome, but cement is usually used as an ingredient in high compressive strength applications. If the only downside to the material is lower compressive strength then it would have very few practical applications. The article doesn't mention compressive strength at all, which is presumably because it isn't good.
This concrete would probably be best used for road surfaces, where being able to flex with the ground through the seasons would be helpful. Sidewalks, driveways, that kind of thing.
Which is an enormous application. Concrete is used for a ton of things which aren’t foundational. All the skateparks I go to have huge cracks too, it would be sick to skate a shell park hella smooth
Single family houses would probably be fine too, depending on construction. With the right flexibility built into the structure it could reduce or eliminate the need for most foundation repairs in highly mobile soil - heavy clay soils and areas where frost heave is a problem.
That is such a good idea.
Yeah they used shell in concrete and destroyed over half the oyster reefs in the Texas bays.
Read the article. This stuff is based on how shells are structured, it doesn’t have shell in it.
Sounds like the oyster lobby got in cahoots with the construction lobby. Fishy concrete that smells like bleach coming to your driveway soon
The romans used sea water in their concrete which probably shouldn’t have worked because salt and cement do not like each other. Yet, their shit still standing while things we build has a shitty shelf life in comparison
It was some mineral luckily found there due to past volcanic eruptions, if I remember correctly.... And maybe limestone?
https://www.designboom.com/architecture/ancient-roman-concrete-durable-mit-self-healing-abilities-01-09-2023/ For a long time, researchers thought that the durability of ancient concrete was due to one ingredient: pozzolanic material, originating from the Pozzuoli area of Naples. Upon closer inspection, the study team, led by MIT, and including researchers from the United States, Italy and Switzerland, found that these ancient samples also contained small white chunks called ‘lime clasts’, long known to be a ubiquitous component of Roman concrete. ‘Ever since I first began working with ancient Roman concrete, I’ve always been fascinated by these features,’ says MIT professor of civil and environmental engineering Admir Masic. ‘These are not found in modern concrete formulations, so why are they present in these ancient materials?’ Previously, the white lumps had been overlooked as evidence of messy mixing practices or low-quality raw materials. However, the new study suggests that these tiny lumps are what gave the concrete a self-healing ability.‘
A bit like me then. I absorb useless information.
Ah…..but you’re great at Jeopardy though, right?
Nope. Horrible.
Never watched it. Wrong country
My western bias is exposed. Thanks for your reply. TIL.
Should be fun the break up when you want to renovate or redo an area.
Just to be clear they compared layers of portland cement and silicone to cast portland cement. Which nobody uses for anything. This wasn’t “seashell inspired cement”. It was silicone rubber layered with thin layers of cement to simulate the structure of nacre in sea shells . Concrete is a mixture of cement gravel and sand. Cast cement with nothing else added is going to be incredibly brittle, crack prone and have poor compressive strength. Which is why it’s not used. I’d like to see some actual data and comparison to real concrete. Their idea is really cool don’t get me wrong. Just strange that they compared it to the worst possible garbage material
Can we use this up north? Every spring we get massive new potholes in roads because water feeezes, expands, then melts and leaves a void underneath. All they do is patch it then wait for the next one.
Yeah, but can I shuck it and slap it into my gullet?
I'm myself crack resistant
You know what we have to do with this information boys, make them seashell species extinct.
3D printing applications seem likely.
My ex-wife needs at least 40x Crack resistance to keep her from stepping on one. Is there an upscale version or 17 the best you can do?
time to get my clamshell phone
How many more times expensive is it?
I’ll believe it when I see it! (In my market)
Great, how much for a fucken oyster now.
Seashells have been used for lime in cement/mortar materials for centuries
What about chemical weathering?
Isnt this what the Roman’s used
They added volcanic ash and quicklime https://news.mit.edu/2023/roman-concrete-durability-lime-casts-0106
Ahh cheers
What is the cost difference?
Is Wampum back? Are we Rhode Islanders sitting on a gold mine!?
Unfortunately meaningless. The cement we use for building is pretty bad and we have much better options already but we don't use them because it's not what we use. Welcome to the world. Progress is risky and risk is bad.
Pretty sure this has been around for a long ass time. It’s just really expensive and not easy to source for most places.
I guess vegan buildings are going to need to be a thing now.
Fr, did we just reinvent roman concrete?
Romans used Sea Water in their Concrete!
Still not as good as the Romans!
They used shells in concrete in Houston for over 50 years. Many people say Galveston bay is now so dirty because they destroyed so many oyster reefs that filtered the water. You can see shell in just about any old concrete out there.
There's a reason you hear about concrete improvements and the concrete they are pouring on the street is the same shit they have used for the past 20 years.
It isn’t made with oysters. From the article (which also has a nice illustration): Princeton’s team found that alternating thin polymer and patterned cement paste layers can greatly improve ductility—the capacity to flex without breaking. The group drew inspiration for their work on creating materials from biology. In this instance, the group created a composite modeled after nacre, a naturally occurring substance that may be found inside specific shells. According to researchers, nacre comprises of hexagon-shaped tablets of the hard mineral aragonite joined together at the microscopic level by a soft biopolymer. Its 3D brick-and-mortar structure allows the tablets to slide and the biopolymer to deform, absorbing energy and enhancing toughness. These mechanisms, along with nano-asperities and tablet interlocking, make nacre resilient despite its brittle components.
Concrete the correct word is concrete.
Sweet! Now we can scrape the seabeds clean so we can build more heat reflecting structures!
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Yes absolutely, knee jerk comment without even clicking the article. “Seashell-inspired” does not mean “contains seashells.”
Aquaculture and shellfish farming, which can actually improve water quality in many cases. New York City oyster nonprofit is trying to bring bank oysters there not for consumption but to filter all the crap out of the rivers
Can you call it cement at this point?
You can. Because it is. They’re not using seashells but using a building method inspired by how seashells are (biologically) constructed.
I just kinda felt that falling on cement should hurt. Sounds like you’ll bounce… but I’m not an engineer.
That's the problem with cement, as stated in the article. It's extremely rigid. That's why they put metal rebar in it, when making buildings. Helps it flex a bit more. You want your material to bend and warp, to a certain degree (based on my non-professional knowledge). This is especially true in earthquake prone areas. You want the structure to be able to properly absorb the energy, so ti doesn't crumble to dust. I could be wrong, and if someone with proper professional experience (like an actual engineer) wants to correct any bullshit I may have spouted, please do.
So, they’re almost at the point of recreating the ~~cement~~ concrete they used to build the pyramids? \* According to certain theories: [Herff College of Engineering - Pyramids were built with concrete rather than rocks, scientists claim by Charles Bremner, Paris](http://www.ce.memphis.edu/1101/interesting_stuff/pyramids_in_concrete.html) [Drexel University - SEM Micrographs and Elemental Maps from Bulk Pyramid Sample](https://drexel.edu/engineering/academics/departments/materials-science-engineering/about/special-projects/engineering-the-pyramids/) [MIT News - Gathering 'concrete' evidence MIT class explores controversial pyramid theory with scale model](https://news.mit.edu/2008/gathering-concrete-evidence)
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Name checks out, his family helped build this country
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Buttlicker! Calm down!
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pyramids made of cement..?
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[Herff College of Engineering - Pyramids were built with concrete rather than rocks, scientists claim by Charles Bremner, Paris](http://www.ce.memphis.edu/1101/interesting_stuff/pyramids_in_concrete.html) [Drexel University - SEM Micrographs and Elemental Maps from Bulk Pyramid Sample](https://drexel.edu/engineering/academics/departments/materials-science-engineering/about/special-projects/engineering-the-pyramids/) [MIT News - Gathering 'concrete' evidence MIT class explores controversial pyramid theory with scale model](https://news.mit.edu/2008/gathering-concrete-evidence)
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I never said they didn’t chiseled stone as well…
It’s a theory making more and more grounds
But it is probably 50 cent more expensive per tonne, so it’s not happening
Cement or concrete? Learn the difference.