Episode 13 Concrete for the Future

Houses you can eat were once the stuff of fairytales.

But now they're becoming reality.

A startup at the University of Tokyo makes these squares of edible cement from food waste.

Orange peel mixed with sugar
tastes pretty good.

A bit hard, though.

The researchers are among many around the globe developing environmentally friendly building materials.

They believe greener alternatives will help realize a carbon neutral society.

Today, we zero in on what could soon be the building blocks of our world.

Hello and welcome to Zeroing In: Carbon Neutral 2050.

I'm Catherine Kobayashi in New York.

People in urban areas often say they live in the concrete jungle.

Buildings, roads, bridges concrete at every turn.

It's highly durable.

But the cement used to make it accounts for 8% of global emissions.

Greg Dalton, the host of the talk show Climate One is here to tell us more.

Greg, welcome back.

Great to have you.

Good to see you.

Well, let's start with the basics.

What's the difference between cement and concrete?

Right, we often talk about them as they're the same thing.

Cement is a binding agent that glues materials together.

It's mainly made of limestone and clay.

Concrete is a durable building material used everywhere for sidewalks and cities, as you said, it's second only to water is the most commonly used commodity on the planet.

You know, it's also a very old material, the Romans made concrete using volcanic ash with lime and sea water.

You know, as I ride across the Golden Gate Bridge, often I looked down and amazed that they built that bridge using cement poured into the ocean in the 1930s.

And recently, I was at the little island here in New York.

And it's very artful and beautiful.

It's these little tulips on the side of Manhattan that form this little island.

So it's ubiquitous, and it's beautiful.

It is beautiful.

But as we know, cement production is polluting I hadn't put too much thought into before.

But why is that?

There're two reasons.

It's so polluting about 35 to 40% comes from the high heat required.

60 to 65%, the emissions come from the chemical process itself, a cement factory breaks down the limestone at very high heat,

and the chemical process releases carbon dioxide.

That means there's two levers for reducing the climate eating gases that come from making concrete one is to produce the heat required from renewable resources,

wind and solar.

The other is to change the chemical process itself, both are possible, but they cost a little more.

Concrete is a commodity.

And producers don't want to do anything that adds even a tiny little cost to what they're doing.

So, it's everywhere.

And it's growing, because there's so much infrastructure being built in emerging economies, roads, buildings, etc.

Let's talk about growth.

The global cement market is projected to grow from $340 billion to more than $480 billion by 2029.

And there are moves to decarbonize production.

California is the second-biggest producer of cement and concrete in the United States, and moves are afoot to make the industry greener.

Officials in the state are turning to a low-carbon alternative called "Portland Limestone Cement."

Expert Tom Tietz told us how it can reduce emissions.

Portland Limestone Cement reduces emissions and production is that it doesn't require as much burning of that limestone.

It's grounded and added later to the process.

Cement is produced by burning limestone and other materials like clay inside a kiln.

And this releases CO2.

But with Portland Limestone Cement, fewer materials are burned.

And finely ground limestone is added at the tail end of production.

Ultimately you end up with a product with exactly the same type of performance, but 10% less emissions impact.

It's very significant.

When you look at the volume of cement used in California and beyond, that 10% adds up.

And it's the first 10% for us to ultimately reach carbon neutrality.

Japan is also getting ambitious on green construction.

It's part of efforts to realize a 46% reduction in emissions by 2030.

Industry ministry officials plan to invest more than 380 million dollars in the development of concrete with a lower carbon footprint.

And the private sector is providing plenty of innovation.

CELBIC is an alternative concrete jointly developed by 13 Japanese general contractors.

It's said to reduce emissions by up to 63%.

The secret lies in substituting a portion of the cement with what's called "blast furnace slag" - a material that puts out significantly less CO2 during the manufacturing process.

It's actually a byproduct of iron and steel production, and has long been considered industrial waste.

But now, it's being reused to harden concrete.

This retail and office development in Tokyo's high-end Ginza district is the first property in Japan to use CELBIC.

Officials firmly believe their low-carbon construction techniques will stand the test of time.

How can we add value
to the properties we build?

We want to make greener construction materials
and methods part of our brand.

We see that resonating
with customers.

To us, this is not a trend,
but the new norm.

So, we will continue developing
these technologies and put them to use.

A major Japanese construction firm is developing another type of concrete that's not only green - but carbon negative.

It's called CO2-SUICOM.

Place it in a high CO2 environment, and it soaks up the gas as it hardens.

The company's conventional concrete emits 288 kilograms of CO2 per cubic meter.

In comparison, their new produce captures 18 kilograms.

The more we use CO2-SUICOM,
the more it reduces CO2 levels.

It’s not carbon-neutral.
It’s carbon-negative.

It’s about carbon utilization,
not decarbonization.

That’s our product's
biggest advantage.

The idea came from a study of some 5,000-year-old concrete discovered in China.

The ancient concrete
was dense and solid.

It was like marble.

Why is it so durable?

How has it remained intact
for 5,000 years?

Our research told us
carbonation was the key.

Further studies revealed the ancient concrete contains a large amount of calcium carbonate.

That's because it has been absorbing CO2 for centuries.

The discovery inspired company officials to develop a special admixture that behaves in much the same way - absorbing CO2 and fixing it to the concrete as calcium carbonate.

It's a miracle of sorts, but challenges remain.

There’s a size limit.

Because we use a curing tank
during the manufacturing process.

That’s where we add CO2 to the concrete.

This is the curing tank needed to carbonate the concrete with highly concentrated CO2.

The current facility makes it difficult to produce the product in large sizes.

For the time being, it's mainly being used for roads and pavements.

Greg, it's fascinating to see wastes becoming building blocks even absorbing CO2 In the process.

It is very exciting.

That concept has been around for more than a decade.

The challenge is commercializing and scaling it at price that really works.

This is one of those really difficult industrial problems to get at.

There are technical factors, like the really high heat needed, chemical process itself.

There're economic factors, like being a commodity where no one wants to add to price.

There're engineering requirements.

You know, people who construct buildings are, want to be very careful to make sure there's structural integrity.

They're very reluctant to do try new things and all industries are moving toward decarbonization, and cement is part of that.

And perhaps industry needs incentives to decarbonize.

Yeah, that always helps and with many areas policy helps move industry faster than they might be otherwise move voluntarily.

Markets won't make changes on their own.

Several states are doing that for low carbon concrete, including Hawaii and New York State.

And count California among them too.

Authorities recently passed a law to lower emissions from cement and concrete.

Our partners at Northern California public media met a lawmaker who authored the bill.

This is what democracy looks like.

No more coal, no more oil.

Keep your carbon in the soil.

California is ambitious on tackling climate change.

State policies include ending sales of gasoline-only cars by 2035.

And another takes aim at the construction industry.

In September 2021, the governor signed a law that makes California the first US state to directly target emissions from cement.

The aim: a net-zero industry by the end of 2045.

The bill was proposed by California State Senator Josh Becker.

This bill that we passed, is the biggest in the country in terms of getting to net zero for cement.

The way we were able to do this with working with both environmental groups and industry.

Industry have realized this is the direction the world is going.

So they were willing to engage with us.

It was still was hundreds of hours of conversations, but they're willing to engage with us to say,

okay, yeah, let's be part of the solution rather than just opposing everything.

And that's how we were able to do this.

And also to make sure that we protected it, California industry if we're going to require this of California

then we don't want to just import cheap cement that is made with all greenhouse gases.

The transition requires innovative strategies, and some are already underway.

Officials at California's Department of Transportation, or Caltrans, have approved the use of low carbon "Portland Limestone Cement" for public works.

They're hoping for a 10 percent reduction in emissions.

Caltrans oversees and maintains over 50,000 lane miles of roads over 20,000 bridges.

We also coordinate very closely with the Federal Highway Administration.

The adoption of Portland Limestone Cement and Caltrans, this is a real game changer for us, really helps us further those sustainability goals and gives us a little more flexibility to lower that carbon footprint.

We work very closely with industry to make sure that when we're making big changes, that we're doing it together and we're doing it in an organized implementation fashion.

Come on in, Tom.

Welcome to our lab.

This is where some of the magic happens.

Officials at Caltrans take a collaborative approach with the industry when it comes to adopting Portland Limestone Cement in their projects.

Caltrans is pushing forward with the industry to develop more varieties of low carbon cements.

We're looking at the quality of materials from different aggregate sources here.

We also do some evaluations of products.

This is actually a plastic product.

We're gonna see if we can use recycled plastic and incorporate them to our bridges and structures and backfills

as there's a good economic use for new material.

Finding solutions that are cost-effective and resilient is no easy task.

But cement industry official, Tom Tietz says the new law presents huge opportunities for the industry as well.

Some people think that we'd be upset about this bill.

It's just the opposite, and why it's so important to us is because so much is used and because of that, we are responsible for emissions.

And we're hopeful that working closely with together with them will help us unlock many of the barriers that we see that need to be taken down that will help

accelerate the pace of change moving forward.

We want to protect those who are innovative, do you want to do that?

Senator Becker is working on even more ways to encourage the cement industry into going green.

He wants concrete listed under the "Buy Clean California Act" - which sets out low-carbon purchasing requirements for government projects.

So now we have to make sure that the state which buys 40% of the concrete in California, we're the fifth largest economy in the world, that the state buys low carbon cement and concrete, so, we're working on that as a next step.

We need to make sure that we're creating the market now.

The market for a low carbon, concrete and cement to say hey, state's gonna buy this low carbon cement and concrete.

Public agencies in North America buy as much as 1/3 of concrete produced annually, so they have leverage in the transition to low carbon construction.

So officials could work with researchers and manufacturers to reshape the concrete industry.

Right.

And that's happening ---the Buy Clean California Act just went into effect July 1.

And that puts limits on the global warming potential of certain building materials, mainly steel and glass used in state construction projects.

Cement isn't on the initial list, it could be added later.

But Colorado, New Jersey, New York all have by clean laws that do include some cement.

At the federal level, the Government Services Administration is responsible for delivering much of the space, the buildings for the federal government, they have earlier this year announced a new standard for contractors

to use low embodied carbon cement in their major construction projects.

So those are state and federal policies that are moving forward on the construction of buildings in the future.

Sounds encouraging, Greg.

But what about the buildings that already exist?

A construction company in Japan is developing a new way to give them a climate friendly facelift.

The concrete jungle could soon act like a real jungle.

This coating is known as DAC - or direct air capture.

Apply it to the surface, and it absorbs carbon dioxide much like a tree.

It was jointly developed by a major Japanese construction company and Hokkaido University.

By applying the "DAC coat," you can double the amount
of calcium carbonate in the concrete.

And that increases the absorption of CO2.

Simply put, this technology gives existing structures the ability to absorb carbon.

It works by chemically bonding CO2 in the air with compounds in the concrete, effectively trapping it inside as calcium carbonate.

The researchers say a single DAC-coated pillar of about 300 cubic meters could absorb as much CO2 with one hectare of cedar forest in a year.

Old buildings are everywhere.

Civil engineering structures, buildings made of reinforced concrete.

We believe our coating can turn them into
forest-like absorbers of CO2.

The coating also protects against corrosion, effectively increasing a building's lifespan.

In Japan, improving the durability of concrete is a major concern.

Our goal is to extend the service life
of aging infrastructure, which will allow us to reduce the need
for repairs and renewals.

That will also help to reduce CO2 emissions
generated over a building’s life cycle.

The researchers are now testing the environmental impact of this coating with an eye on putting it into practical use in 2026.

We can apply this technology to a
vast amount of surface area.

That means the potential to absorb
huge amounts of CO2.

I think it will have a big impact.

Greg, that is such an interesting idea.

The coating.

The coating sounds promising, and I hope it works.

It also reminds me a little bit of some things I heard about a decade ago about windows that could generate solar power with some coatings.

You know, that didn't play out as the company and some people expected.

You know, other companies are still trying.

Maybe that will work out.

It often takes many attempts at these kinds of new innovations to find success.

You know, Google was not by far the first internet search engine.

It's the one we know today.

So innovation requires, involves failure and many attempts at these things.

I feel optimistic companies are pushing for change.

But what about us as individuals?

What can we do?

Right.

Most people don't buy concrete or cement, you know, every day or every every year in their life.

So many people do when they do that they can ask for low carbon concrete.

And when I built a new deck in my house, I had to have a concrete foundation because we're near a creek and we're in an earthquake zone.

I asked the manager, "can we get low carbon concrete?"

He said, "Yeah, I think I've heard of that."

And then there was kind of a conversation of the architect and the builder.

Where do we get it?

So we did get some concrete that has fly ash, which is a byproduct of burning coal.

There were concerns about whether it be strong enough, etc.

So we at Climate One believe that curious conversations that's the way change starts by people asking questions, having conversation and moving things forward.

So have the conversation.

Right.

Great insight.

Thank you very much.

Thank you, Catherine.

We'll wrap up with something we saw earlier, edible concrete being developed using food scraps.

And a few thoughts from one of the researchers have this novel idea.

These colorful, cookie-like squares are each made with a different ingredient.

Sweet potato.

Tea leaves.

Napa cabbage.

And bread.

They're the result of a new technology that transforms food waste into building materials.

And we can thank Machida Kota for their existence.

He researched sustainable alternatives to concrete as an undergraduate at the University of Tokyo.

In 2021, he started a company that produces the edible squares.

My research lab was developing
sustainable construction materials.

And I had an interest in
the issue of food waste.

I wanted to make new materials
using scraps and inedible waste.

That’s what we’re researching.

The process is pretty simple: the scraps are freeze dried and pulverized.

And then they are heat-compressed in a mold for several minutes.

We still need more verification,
but we hypothesize that the sugar in the food
combines with the fiber.

Think of the sugar as the adhesive
and the fiber as the reinforcement.

Depending on the food, this cement can be as much as four times stronger than conventional concrete.

And for Machida, the most important thing is that the materials retain their edible nature.

He's committed to making cement that is 100% food-derived and additive-free.

The fact that they’re naturally derived
is part of the appeal.

During Japan’s Warring States period, people put plant stems
and dried gourds into castle walls

to serve as food when
they were under siege.

So, it’s not unheard of.

There are plans to use Machida's material for the interior of a building at the 2025 World Expo in Osaka.

I want to make a house with it.

My ultimate goal is to produce
next-generation construction materials that can be used instead of concrete
in buildings and infrastructure.