transcript

Speaker 1:
[00:01] I've lived in 10 different cities over the last 20 years, mostly in the US., from the dense urban jungles of the Northeast to the sprawling communities and commutes of the South, and even a few extended chapters in Central and South America. I'll admit it, I love cities. I love the texture of a walking neighborhood, the smell of the best local food, and the way a city's history and soul is often reflected in its infrastructure. But no matter what zip code I've called home, I've found myself obsessed with one thing, the roads. You can tell a lot about how a city values its citizens by the quality and shape of its asphalt. In Atlanta, I lost track of the number of times I've braced for impact over a pothole. In Miami, navigating the roads after a heavy downpour takes a bit of strategy. The wrong choice leaves your car stuck in a newly created mini-lake before you even reach your garage. We tend to think of potholes and damaged roadways as these one-off experiences. But the reality is that they are symptoms of a massive systemic failure. Whether a city relies on tolls or gas taxes, the demand for road repairs always outpaces the budget. Our current system just can't keep up with the need. So what if there was a better way to fix our major infrastructure problem? This is TED Tech, a podcast from TED. I'm your host, Sherrell Dorsey. I want to share two talks that focus on how to repair critical infrastructure like roads and bridges. From our first talk, I want you to imagine a future with fewer damaged cars, fewer fatal accidents, and an end to the build, break, discard cycle. The ongoing pattern where we build new things, but just get rid of it when it breaks. Instead, this future is a generative one, where infrastructure isn't just a static object, but a living partner. That's the vision that today's speaker shares in his talk. Instead of starting from scratch every time something stops working, material scientist and engineer Mark Miodognik wants us to get better at repairing the infrastructure we already have. Mark's work explores animate materials, substances engineered for self-repair and autonomous motion. He believes these are the smarter materials that can help usher in a greener, more sustainable global infrastructure where we stop building to replace the old, and start building to evolve instead.

Speaker 2:
[02:46] If you come and visit me in London, you'll see streetscapes a bit like this. And if you see the world through my eyes, you'd see this. Don't pity me, okay? I love this stuff. We just make so many amazing materials as humans. In fact, that's what we do. We have done that for thousands of years. We make stuff. At the first, we made tools, which allow us to make clothes, and then it allowed us to make shelter to protect us from storms and from the weather. And containers allowed us to store food so we could survive the winters. And then, then we started to dream big, you know? We started to make boats, and we started to make materials that cured toothache, and we made stuff that could harness electricity, and we made airplanes, and we made stuff that could go to the moon. I mean, this is who we are, we make stuff. Why do we make so much stuff? Well, it represents who we are, this is who humans are. We like to make stuff, we like to dream big, we like to create. So that is why civilization gets pushed forward. It's why the ages of civilization are named after materials. We have the Stone Age, we have the Copper Age, we have all the ages until now. But there's a problem. You're all familiar with an image of a pothole. You've all driven straight into a pothole, or, you know, on a bike, been thrown off your bike by hitting one of these potholes. They're a menace. If you're on an e-scooter, you just disappear right down them. All of our stuff, we got so good at making it, but we're not so good at repairing it, we're not so good at taking care of it. And that is our next big task, our next adventure as humans. So what would a future like that look like? Imagine a city now as a future, but imagine one that doesn't constantly fall apart, that doesn't constantly have potholes and cracks in bridges, that when a storm hits and a small is damaged, then it heals itself. What would that be like? Could we do it? Can we make bridges, tunnels, roads, buildings that repair themselves? The answer is some stuff called animate matter. And what is animate matter? Well, animate matter is a different form of material. We're borrowing from nature. It's a form of material that repairs itself, heals itself, actuates, senses the environment. Is it impossible to make? No. We're making it now. People in my lab, hundreds of people in labs all over the world are making this stuff called animate matter. But to tell you how it works, I first need to take you inside materials. I need to show you how they work. So this is how we material scientists understand the material world. This is how we design new materials. You got big stuff at the top, and you get smaller, smaller, smaller, smaller, smaller. So you can see the natural world, how nature builds materials. You have trees, and then you have whales, and they have mice, and then you have fleas on the mice, and they have the hairs on the fleas. And inside those, you have tissues, and there are many types of tissues. We have skin tissue, lips, we have brain tissue. Then you zoom in further, you get single cells, and then you zoom in further, and you get the whole molecular machinery of cells, and you zoom in further, and you get the DNA. And it's the DNA that builds those machines, and the machines that build the cells, and cells build the tissues. And so you get the idea. The way nature builds materials is that it stacks every layer on another, that they are all grown inside each other. Big stuff contains small stuff. We are multi-scale materials. And what is life, then? What is it to be alive? Well, it's the connection between those scales. The scales themselves are physics and chemistry. But the stuff that connects them, the information, they check each other, they repair each other. If they find some damage, they repair that. And you're doing it now. All right? You are repairing yourself now. You get a scratch, your body just goes to work repairing it. So nature builds materials, but it builds self-repaird materials. Now, we've built materials, too. We've built amazing materials, massive bridges, cars, phones. We've mastered these different scales. We can zoom in, we can make nanostructures, we can manipulate atoms, we can make transistors. But what we really lack is the ability to connect those scales up and get them to self-repair. And that is the big next challenge. Can we do it? Well, look, let me take you through some work that we're doing that we're already making great progress. So self-repairing roads. When we analyzed the roads, we realized that big potholes start off as tiny microscopic cracks. And the key to stopping them doing runaway growth into a pothole is to catch them early. If you zoom in now, and we started to look at the different structures inside roads, what we found are mulled teams and micelles, and actually, they can self-repair. They actually can move around. But you need to give them impetus. You need to give them energy. So we put embedded nanoparticles into that material. And by actuating with magnetic field, we can get them to move around and self-repair the microcracks before they become potholes. Another example, self-repairing concrete. There are people in the world who have been making this for quite a while now. You can buy this stuff. How does it work? Well, inside the concrete are tiny microorganisms placed there by the concrete manufacturers. When a big storm hits and a crack opens up, the microbacteria wake up, they smell the humid air, they look around for food, they find starch that's been left there by the designers of the concrete, they eat it. They do a poo and they poo calcite. Yes. They eat their way out of the crack, leaving pristine material behind them and restoring the concrete to 90% of its original strength. It works today. Self-disassembling plastic. So we've been working on this problem that you put, you need to put plastic wrappers around small seedlings to grow trees, to reforest the world. But the problem is the plastic itself then pollutes the world. So can we get a material that is, protects the tree for years on end, but when that tree is mature, will then disintegrate and become biodegradable? Answer yes. We are embedding little tiny enzymes that catalyze the disassembly of those polymers, of those plastics. And we get them into the plastic by wrapping them in a random hetero-polymer. And that allows them to survive the process, the high-temperature process of making the plastic, and to survive in the environment until they're needed. And then they come out and it disintegrates. And we'll fill testing this now. So these animate materials I'm talking about, they are really extraordinary, and they are possible now. We are making them. And they make self-repairing roads, self-repairing bridges, and biodegradable materials much more tangible in the future. So what are the problems we face? It's not so much the technical stuff. We can do the technical stuff. Probably one of the biggest hurdles is the economics. At the moment, we have a system where we make stuff, it falls apart, we remake it, it falls apart. And we throw the waste away into the environment. We do this with roads, we do this with buildings, we do this with electronics, we do this with clothes, we do this with pretty much everything. And we're basically just piling our materials, our wonderful materials, the ones that we've made over time in Memorial, we just throw them away as if we don't care. And we've got to stop. We've got to take care of our materials. But we need a new economic model. The consumerist model doesn't work for a sustainable future, for a non-polluting future. And I think animate materials will play a really big part in making those future. And when we calculate the costs of that pollution and that global warming, then they'll start to make sense economically. So what would we feel like, though, to live in this world, to live in a world that is animate? Well, I think in 20 years' time, you come to visit me in London, and the animate materials are now in the infrastructure and in our phones and in our laptops. I don't think it will feel weird. I think it will feel a bit like being in a forest, right? You go into a forest, all of that stuff is looking after itself, repairing itself, building itself. In fact, we could push these animate materials to make themselves. Perhaps we could make roads that build themselves. And then, what would our job be? Our job wouldn't be to constantly have to repair things, to borously throw things away, remake them. Our jobs would be more like gardeners, right? Yeah, the city would look after itself. We could enjoy ourselves. Occasionally pruning a road that was drifting off into the wilderness, yeah? Or it had rebuilt a bedroom of yours and you didn't quite like the design, you could push back on it a bit. But that, that is the world we're heading towards. That's the future, a future where we take care of our stuff. Thank you.

Speaker 1:
[12:08] That was Mark Miodognik at TED 2025. Mark's vision of animate materials offers more than just scientific curiosity but an environmental necessity. Concrete is the second most consumed substance on earth, surpassed only by water. It's actually what most of our world's buildings and infrastructure are made out of. But that scale comes at a price. The cement industry alone is responsible for about 8% of global carbon emissions, reducing its footprint through repair, reuse, and better materials could bring this number down significantly. If we want our infrastructure to last centuries instead of decades, we have to stop thinking of it as a dead static object. Maybe we can start thinking of it as a biological system instead. In this next segment, a TED ed lesson, we dive into the microscopic world of bio-concrete. It's a compelling idea where the secret to fixing our crumbling bridges might not be a better jackhammer but a specific strain of bacteria waiting for a drink of water.

Speaker 3:
[13:27] Concrete is the most widely used construction material in the world. It can be found in swaths of city pavements, bridges that span vast rivers, and the tallest skyscrapers on earth. But the sturdy substance does have a weakness. It's prone to catastrophic cracking that costs tens of billions of dollars to repair each year. But what if we could avoid that problem by creating concrete that heals itself? This idea isn't as far-fetched as it may seem. It boils down to an understanding of how concrete forms and how to exploit that process to our benefit. Concrete is a combination of coarse stone and sand particles, called aggregates, that mix with cement, a powdered blend of clay and limestone. When water gets added to this mix, the cement forms a paste and coats the aggregates, quickly hardening through a chemical reaction called hydration. Eventually, the resulting material grows strong enough to prop up buildings that climb hundreds of meters into the sky. While people have been using a variety of recipes to produce cement for over 4,000 years, concrete itself has a surprisingly short lifespan. After 20 to 30 years, natural processes like concrete shrinkage, excessive freezing and thawing, and heavy loads can trigger cracking. And it's not just big breaks that count. Tiny cracks can be just as dangerous. Concrete is often used as a secondary support around steel reinforcements. In this concrete, even small cracks can channel water, oxygen, and carbon dioxide that corrode the steel and lead to disastrous collapse. On structures like bridges and highways that are constantly in use, detecting these problems before they lead to catastrophe becomes a huge and costly challenge. But not doing so would also endanger thousands of lives. Fortunately, we're already experimenting with ways this material could start fixing itself. And some of these solutions are inspired by concrete's natural self-healing mechanism. When water enters these tiny cracks, it hydrates the concrete's calcium oxide. The resulting calcium hydroxide reacts with the carbon dioxide in the air, starting a process called autogenous healing, where microscopic calcium carbonate crystals form and gradually fill the gap. Unfortunately, these crystals can only do so much— healing cracks that are less than 0.3 millimeters wide. Material scientists have figured out how to heal cracks up to twice that size by adding hidden glue into the concrete mix. If we put adhesive-filled fibers and tubes into the mixture, they'll snap open when a crack forms, releasing their sticky contents and sealing the gap. But adhesive chemicals often behave very differently from concrete, and over time, these adhesives can lead to even worse cracks. So perhaps the best way to heal large cracks is to give concrete the tools to help itself. Scientists have discovered that some bacteria and fungi can produce minerals, including the calcium carbonate found in autogenous healing. Experimental blends of concrete include these bacterial or fungal spores alongside nutrients in their concrete mix, where they could lie dormant for hundreds of years. When cracks finally appear and water trickles into the concrete, the spores germinate, grow, and consume the nutrient soup that surrounds them, modifying their local environment to create the perfect conditions for calcium carbonate to grow. These crystals gradually fill the gaps, and after roughly three weeks, the hard-working microbes can completely repair cracks up to almost one millimeter wide. When the cracks seal, the bacteria or fungi will make spores and go dormant once more, ready to start a new cycle of self-healing when cracks form again. Although this technique has been studied extensively, we still have a ways to go before incorporating it in the global production of concrete. But these spores have huge potential to make concrete more resilient and long-lasting, which could drastically reduce the financial and environmental cost of concrete production. Eventually, these microorganisms may force us to reconsider the way we think about our cities, bringing our inanimate concrete jungles to life.

Speaker 1:
[17:41] Bioconcrete is already a material category being developed and deployed around the world. For instance, in Quito, Ecuador, engineers developed a strategy called geotechnical soil stabilization in their roads and highways. This involves a mix of techniques like polymer additives and soil cement to create stronger, more durable roads and challenging terrains, all without using any toxic stabilizers. Healing concrete can also have other uses. In Malta, a historic 1930s water tower was restored with a healing concrete material, earning an Energy Global Award in 2022. Governments are now embracing the potential of biomaterials. Many have implemented procurement laws mandating their use in local infrastructure projects. Take New York State. The Buy Clean Concrete Mandate that went into effect in 2025 requires state-funded projects to meet strict carbon limits, essentially forcing the adoption of low-carbon and bio-based alternatives for any contract awarded over $1 million. China is incorporating self-healing concrete into massive infrastructure projects under the Belt and Road Initiative, specifically for highways and ports, where durability is a financial priority. And through the European Green Deal, the European Union is funding massive R&D projects to standardize the use of ultra-high durability bioconcrete in seismic and marine zones. These initiatives make me feel hopeful about the future. There's a long road ahead of us, but a lot is possible when we consider creative, innovative solutions to our biggest problems. TED Tech is a podcast from TED. This episode was produced by Rahima Nassar. Our editor is Alejandra Salazar, and the show is fact-checked by Julia Dickerson. Special thanks to Consonza, Gallardo, Daniela, Belareso, Maria Ladias, Tanzika Sangmanivan, and Roxanne Hylash. If you're enjoying the show, make sure to subscribe and leave us a review so other people can find us too. I'm Sherrell Dorsey. Let's keep digging into the future. Join me next week for more.