Self-healing sea walls – sci-fi dream or eco-friendly reality?

Self-Healing Concrete Sea Walls

For many people, the sea is one of the best things about living in Britain. Our coastal towns and villages are idyllic places to live, work, and visit, and millions of us flock to the seaside when the sun shines.

However, that same sea is steadily eating away at our coastlines. In storm surges, it has been known to swallow up entire settlements. Many of the villages the Romans found when they landed here are now fathoms deep under the sea – and miles away from the retreating coastline.

The sea is both a precious resource and a terrible threat. For centuries, we have battled with the problem of how to protect our seas and to defend the island against them. From moats and channels that divert floodwater to high walls designed to break the power of battering waves, we’ve been holding the sea at bay for a long, long time.

Current sea defences use a huge amount of concrete. Concrete is versatile, durable, and plentiful, so it makes sense as our first line of defence against the battering waves – but it’s far from perfect. Maintaining our concrete sea defences costs hundreds of billions of pounds every year, and all that concrete can be devastating for sensitive marine habitats.

Because of this, defending Britain from the sea can feel like an uncomfortable trade-off between human safety and the health of our seas.

Now, as remote working becomes more viable and popular, the lure of our beautiful coastline grows stronger and stronger. As people take up new lives by the sea, there is more pressure than ever on the delicate balance between human interest and marine environment.

We have a game changing solution. Our self-healing concrete could not only align the needs of coastal environments with our own needs – it could also save billions of pounds. We hope that our self-healing concrete precasts will usher in a new era of bio-structures in which humanity works hand in hand with nature to protect our coasts.


How is this possible? Let’s take a look:


Corrosion, cracking, and environmental collapse – the problems with standard concrete defences

First, let’s be selfish and look at the problems standard concrete defences cause for humans:

  • Corrosion. Concrete – especially concrete exposed to coastal environments – doesn’t last forever. Freeze/thaw cycles, persistent nibbling by saltwater, the battering power of storm-surge waves – all of these cause damage to concrete structures. This damage compromises structural integrity, necessitating a lot of repairs. Which brings us to our second point…
  • Expense. Repairing concrete defences is a constant concern for coastal councils. Keeping our sea-walls and other marine structures safe and viable costs the country billions and billions of pounds annually.

But concrete sea defences don’t just come at human expense. The cost to the environment is astronomical. Knock-on environmental effects include:

  • Greenhouse gases. Concrete is one of the leading causes of Co2 in the planet’s atmosphere. It’s estimated that 8% of all total emissions come from concrete construction.
  • Habitat disruption. Submerging huge concrete structures in the ocean disturbs and, in some cases, destroys delicate marine habitats.
  • Pollution. Submerged concrete can alter the pH of seawater, making it impossible for fragile marine organisms to survive.

All in all, our concrete sea-defences are expensive, a drain on the economy, and terrible for the seas we love so much.

Is this a necessary evil? Is the cost (both human and environmental) a price we just have to accept in order to protect human life and property from stormy seas?

We don’t think so. We have a solution that not just makes concrete better for human purposes – but which protects the environment in the process.


Concrete that heals itself – sci-fi dream or working reality?

A wall that rebuilds itself sounds like the fever dream of a sci-fi writer. But such a thing has existed for hundreds of thousands of years.

Coral reefs are natural ‘walls’, built by coral polyps which exude calcium carbonate (limestone). Coral reefs have, entirely naturally, protected coastlines for thousands and thousands of years. They’re impressive structures that have repaired and replaced themselves for millennia, without any need for human intervention.

Now, we’re not proposing to seed the UK’s coastlines with coral – but we can do the next best thing. Using self-healing concrete additive Basilisk, we can create ‘bio-walls’. These structures mimic nature and natural processes to provide coastal communities with natural, self-healing sea-defences that work in harmony with the environment.


How does self-healing concrete work?


Basilisk is a nutrient-rich solution containing microbes which produce calcium carbonate. It’s added to concrete as it’s mixed, and the microbes lie dormant within the structure until cracks appear.

When the concrete cracks, the microbes are exposed to air and water. This activates them, and – just like coral polyps – they start producing calcium carbonate. As the limestone builds up, they move through the crack, sealing it behind them as they go.

Once the crack is filled with calcium carbonate, the microbes go back to sleep.

Sealing up cracks gives concrete a much longer lifespan. It prevents iron rebar within the structure from corroding, preserving structural integrity. This keeps concrete structures strong, resilient, and reliable for much, much longer than would otherwise be the case.

As well as making our sea-defences safer, our self-healing concrete precasts could save the country billions in repairs, and drastically slash the carbon cost of coastal construction.

But the benefits don’t end there.


Protecting humans, providing habitat: biomimicry and sea-friendly concrete

Our precast sea-defences are designed to adapt perfectly to their specific environment. We use biomimicry technology to emulate the shapes of nature. Rather than being presented with an alien, featureless wall bisecting their habitat, sea-creatures are provided with a rich and attractive habitat in which they can thrive.

To make absolutely sure that our concrete works with rather than against its environment, we carefully balance its pH to match that of our coastal seas.

Yes, humans and nature can live in harmony – self-healing sea defences prove that it’s possible

Our precast self-healing concrete structures improve sea defences both for humans and for the planet. As well as slashing construction costs and making sea defences much more reliable, they create a harmonious environment for marine life and cut carbon emissions.

Eco-conscious construction is the future. Without it, the UK can’t hope to meet our carbon-neutral targets. We’re leading the way in sustainable construction – improving concrete structures both for people and the planet.

Want to know more about our eco-concrete products? Read about Sensicrete