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  • [♪ INTRO]

  • Right now, the construction industry heavily relies on concrete.

  • And for some good reasons.

  • Concrete is cheap, and it is a highly efficient way to build safe and secure buildings.

  • But it's also so bad for the Earth.

  • It takes huge amounts of energy to produce and ship this stuff, and these days,

  • concrete alone produces about 8% of global carbon emissions.

  • In 2018, that translated to almost 3 billion metric tons of carbon dioxide.

  • So while concrete is convenient and all, it would be great if we could find an alternative

  • and start making our buildings out of something else.

  • Well, maybe shockingly, we're not actually the first people to have had this thought!

  • Many scientists are already conducting research into the materials of the future,

  • and some of their ideas are so off the wall that they just might work.

  • Here are six of them.

  • Let's kick things off with one of the weirder examples: synthetic bone.

  • Because, you know. Living in a building made of real bones, that would just be too upsetting.

  • Scientists at Cambridge have been working on this project since around 2011,

  • and although it may seem odd, there are several good reasons for using bone-like materials in construction.

  • For one, bones are incredibly strong for their size and weight.

  • A bone fragment the size of a sugar cube can support over 1500 kilograms,

  • more than some types of concrete.

  • Also, thanks to their structure and composition,

  • bones are very elastic and resistant to fracture and breaking.

  • They're made of minerals like calcium and phosphate, along with the protein collagen.

  • That collagen clusters into long fibers, and it combines with the mineral in just the right way

  • to create a strong, flexible matrix.

  • Your body made this kind of matrix over years of development, but to make synthetic bones,

  • scientists have found ways to speed up that process.

  • To make their material, they dip a small template into a solution of calcium and collagen proteins.

  • Then, they dip that into a solution of phosphate and collagen proteins.

  • And back again.

  • This process is repeated over and over, layer after layer,

  • until it creates a sample that mimics the strength and structure of natural bone.

  • This method is great, and if we could get it going on a large scale,

  • it seems like it could be a cool alternative to concrete.

  • But it does have its downsides.

  • Right now, the biggest problem is that the only good place to get collagen is from animals.

  • This protein is super hard to replicate in the lab,

  • so if we wanted to build something from synthetic bone, we would need a lot of animal parts.

  • And while we could use waste from the meat industry, even that might not be enough.

  • So until we figure out synthetic collage, don't expect to see super goth, bone cities any time soon.

  • But, that doesn't mean they're off the table.

  • So I want to see it in your scifi short stories!

  • Next, the magic of mushrooms is at it again.

  • While some teams are looking for materials that outperform concrete,

  • others are just looking for things that are safe for the environment.

  • And that's led them down some weird paths.

  • Take the work of an architectural team known as The Living.

  • In 2014, they designed and built a 12 meter-tall castle,

  • the first and only building to be made of nothing but fungi.

  • The bricks in this tower were made of recycled mycelium,

  • which are thin, branching structures that look similar to roots.

  • The mycelium was collected from fungi that grew on agricultural waste,

  • like corn and wheat crops, so it was a totally sustainable and renewable material.

  • And the bricks weren't that hard to make, either.

  • To create them, researchers placed organic materials, anything from dirt to nut shells,

  • full of mushroom spores into a brick mold.

  • And in only 5 days, the mycelium had grown dense enough to make a brick.

  • As a bonus, because these blocks are made from fungi, they're totally compostable.

  • If you throw them in a compost heap, they would be dirt again within sixty days.

  • Still, just because these bricks are eco-friendly doesn't mean they're strong.

  • They can withstand only about 0.2 megapascals of pressure,

  • which is less than 1% of what concrete can handle.

  • Realistically, that means we will not be building mycelium cities.

  • Instead, researchers have suggested that we could combine the mycelium with other things

  • to make more stable structures.

  • So, it's a start!

  • Both synthetic bone and mycelium are pretty futuristic materials,

  • and it's going to take a lot of work to figure out how they might fit into our world.

  • But this next example might be pretty easy to adopt.

  • In 2013, scientists at MIT developed 3-D-printed, reusable bricks that function a lot like LEGO bricks.

  • Except, instead of being made of regular plastic, they're made from a carbon-reinforced epoxy resin.

  • Epoxy resins are a group of materials that easily form strong bonds with other materials,

  • like glass or carbon.

  • They're exceptionally strong and very resistant to erosion or damage.

  • And in this case, since they're being 3-D printed, they're customizable, too.

  • Engineers can make structures stronger or more elastic by assembling the resin bricks into different shapes.

  • Now, to be clear, most epoxy resins aren't that environmentally friendly.

  • They're basically a type of plastic, and plastic is, you know, terrible for the environment.

  • It requires a lot of natural resources to make and takes forever to disintegrate.

  • But these bricks try to make up for that by being extremely reusable.

  • They're easy to retrieve when a building needs to be taken down,

  • and they can be used again and again for new buildings.

  • Also, these things are surprisingly strong.

  • Structures made from them can withstand 12.3 megapascals of pressure,

  • which is incredible for such small and light materials.

  • For comparison, average concrete can withstand 17 to 28 megapascals of pressure.

  • And it's much heavier and worse for the planet.

  • Researchers believe these blocks might not be strong enough for skyscrapers,

  • but they could be used in much smaller buildings, like houses.

  • And it's not hard to imagine a future where a crew shows up, stacks a bunch of blocks together,

  • and creates the shell of a house.

  • So again, if these bricks can be mass-produced, it could mean great things for construction.

  • The last 3 examples have been pretty innovative,

  • but they've almost entirely ditched traditional building materials and gone in new directions.

  • That's great, because new ideas can lead to big places.

  • But it also means that it might be a while before these things hit the primetime.

  • These next examples, though, are a bit different:

  • They're more practical, and probably wouldn't be as expensive to implement on a larger scale.

  • So you might be seeing them enter the market a bit sooner.

  • One option like this is called AshCrete, and it's a modified version of concrete.

  • Standard concrete is made by using cement to bind together small aggregates

  • like sand, gravel, or crushed stone.

  • This makes it heavy and hard to transport, but also, those aggregates aren't sustainable.

  • We only have so much sand and stone to throw around.

  • Enter AshCrete.

  • It's an alternative concrete made using ash from waste-incineration facilities as the aggregate particles.

  • It can be used in many of the same places as traditional concrete,

  • and it allows those waste facilities to recycle some of their ash.

  • So, win-win.

  • Unfortunately, although it can solve some of concrete's problems, it's not perfect.

  • Most notably, making and transporting AshCrete requires the same amount of energy as concrete,

  • and this new material isn't great for all climates.

  • Compared to regular concrete, AshCrete can take longer to solidify,

  • and it's more susceptible to cracking from freeze/thaw cycles,

  • since it doesn't trap as many insulating air particles.

  • So it has its flaws.

  • But if we want to start rolling out better materials for the planet soon,

  • it might be a good place to begin.

  • And besides Ashcrete, there's also a number of other materials that try and improve upon things we have now.

  • For instance, scientists have also thought about trying to reinforce clay bricks

  • with 2 of the most renewable substances we've got: wool and seaweed.

  • Which sounds weird, but would work surprisingly well.

  • Although they don't get as much attention as concrete,

  • regular clay bricks are a huge pollution problem

  • because they require a ton of energy and natural resources to make.

  • Like, not only do you need things like soil, sawdust, sand, and lime to make the brick,

  • but then you have to fire it.

  • And that means you have to burn things like wood or coal,

  • and that results in a bunch of carbon emissions.

  • One way companies try and clean up this process is by making what's called a non-fired brick,

  • where you use machines to smash a bunch of clay together and then let it dry in the sun.

  • The problem here is that the final product typically isn't as durable as a fired brick,

  • but there might be a way to change that.

  • At least, according to a 2010 paper published in the journal Construction and Building Materials.

  • In that paper, two architects suggested using wool and seaweed to make these bricks even stronger.

  • In these blocks, wool fibers are mixed with a natural compound from seaweed called alginate.

  • Then, that's mixed into traditional, non-fired clay bricks.

  • The alginate acts as a binder instead of sawdust,

  • and the wool fibers increase the strength and structure of the bricks.

  • By a lot, actually!

  • Traditional non-fired bricks have an average strength of around 2.3 megapascals.

  • But in a test, scientists demonstrated that when both alginate and wool are added to the blocks,

  • the strength increased to around 4.4 megapascal, almost double!

  • That would make them great for things like walls, small houses, or decorating.

  • And with much less of an impact on the planet.

  • Finally, our last and most practical example!

  • Because, look, sometimes the future starts small, and that's okay.

  • Say hello to the pollution-absorbing brick.

  • These bricks were developed in 2013, and admittedly, they are made of traditional concrete,

  • since that allows them to be competitive with current materials.

  • But they're trying really hard to make up for that.

  • These blocks take in pollution from the outside air,

  • and then release clean air into your building through a traditional ventilation system.

  • So these things have two main components.

  • The first is, of course, the brick itself, which faces the exterior of the building.

  • Each brick has a cyclone air filtration system in it,

  • which creates a super fast spiral vortex inside the brick, sort of like a mini hurricane or a centrifuge.

  • As the vortex spins, the heavy pollutant particles drop to the bottom of the vortex

  • and are deposited into a collection hopper at the bottom of the wall.

  • The second component is the recycled plastic couplers, which go between each of the bricks.

  • These couplers both help align the bricks