Go to CuriosityStream.com/SciShow to learn more.

[♪ 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

and allow air to get into the center of the bricks and the filtration system.

The blocks can trap about 30% of pollutants from the air the touch,

as well as 100% of coarse particles like dust.

This makes them a great potential way to passively clean up the air in our cities.

So even though it won't solve our concrete problem, it is a start.

And it could likely help us with at least some of our environmental woes.

There's a ton of cool research being done into alternative construction methods,

and the list goes way beyond these six examples.

That's important to keep in mind, because any one of these solutions probably can't

make construction eco-friendly all by itself.

We're likely going to need tons of alternative options,

so the more ideas there are, the better we might be.

And things seem to be moving in the right direction, at least, based on these projects.

And one way or another, it's cool to see what kinds of solutions engineers are coming up with.

Even if I never get to live in like, a sweet bone building.

If you enjoyed this episode of SciShow, there's another video series you might like.

It's called Digits, and you can find it on CuriosityStream.

CuriosityStream is a subscription-based streaming service,

and they offer more than 2400 documentaries from filmmakers all over the world.

Digits is a series about the physical heart of the Internet, and it has a really futuristic vibe,

kind of like this episode of SciShow.

It's hosted by Veritasium's Derek Muller, and it talks about how the Internet got here

and where it's headed.

If you want to give it a watch, you can get 31 days of CuriosityStream completely for free

if you sign up at CuriosityStream.com/SciShow and use the promo code “scishow.”

After that, you can get unlimited access for just $2.99 per month.

When you sign up for CuriosityStream, you're also supporting SciShow

and helping us make more content like this.

So thanks for considering it.

And we hope you learn something cool.

[♪ OUTRO]