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Build This Roman Concrete Mix: Self-Heals Cracks and Gets STRONGER Over Time (3 Ingredients)

Medieval Wisdom

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For two thousand years, Roman structures like the Pantheon and Ponte Fabricio have survived earthquakes, floods, and time itself — while modern concrete crumbles in fifty years. In 2023, MIT researchers finally cracked the secret: an ancient mixing technique called "hot mixing" that creates concrete with built-in self-healing capabilities. In December 2025, a frozen construction site in Pompeii confirmed everything. This video breaks down the three-ingredient recipe, the one critical step that engineers got wrong for two centuries, and how you can build with this material today.

SOURCES

Seymour, L.M. et al. (2023). "Hot mixing: Mechanistic insights into the durability of ancient Roman concrete." Science Advances, 9(1), eadd1602.
Vaserman, E. et al. (2025). "An unfinished Pompeian construction site reveals ancient Roman building technology." Nature Communications, 16, 10847.
MIT News (2023). "Riddle solved: Why was Roman concrete so durable?"
MIT News (2025). "Pompeii offers insights into ancient Roman building technology."
ASCE (2025). 2025 Report Card for America's Infrastructure.
ARTBA (2024). National Bridge Inventory analysis — 42,067 bridges in poor condition.
Smithsonian Magazine (December 2025). Coverage of Pompeii concrete discovery.
Chemistry World (December 2025). "Romans' hot recipe for self-healing concrete unravelled in Pompeii."
CNN (December 2025). "Ancient Pompeii construction site reveals the process for creating Roman concrete."

roman concrete recipe, self-healing concrete, MIT roman concrete study

00:00 DROP A COMMENT
02:08 THE MODERN FAILURE
05:42 THE CODE BREAKER
11:20 THE FROZEN CONSTRUCTION SITE
14:58 THE BUILD
19:27 THE PROOF

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20 Comments

@MedievalWisdom Creator 1 month ago Pinned

The Pantheon's concrete has lasted almost 1,900 years. MIT figured out why in 2023, and the buildable version is in the guide: https://medieval-wisdom.com

Which would you build first: concrete, waterproofing, or a foundation?

@othername1000 6 months ago

All I need now is a volcano

@Lynnek8 5 months ago

The Roman’s had the best concrete we need to get this commercialised again for options that builders can engineer with.

@cathrynmartin4395 6 months ago

Actually, my house in a very old suburb of Cincinnati, OH used limestone rocks to form the driveway. I have limestone rock steps from the driveway and the street-sidewalk up to my house. Built in 1920, those massive limestone rocks were unearthed during the construction of my house and used to create the driveway and steps as well as a couple of short walls around the front of the house. They have ancient creature's calcified remains embedded in them - mostly trilobytes, but I've seen others that I can't name. Blessed or cursed with huge rocks during the building phase of the house, it certainly made my home unique to an era of "make do with what you have!"

@miguelalicea760 6 months ago

Thanks for the information. I found it to be well researched but I have a constructive critique. You mention the three important materials but you don't mention any mixing proportions of the materials or the amount of water needed. I thing you are aware that the wrong mixing proportions would create a completely different result and simply assume that viewers already now that crucial information. It would be nice is you could provide some guidance in that regard. Thanks again! 😊

@robertmiller5735 6 months ago

The concrete interstate highway system built after ww2 , is still perfect . 70 years later we still drive on the bare concrete of I95 from Greenville SC to Atlanta GA . We can make it , we just refuse to .

@oxyd2013 4 months ago

Louis Vicat, a french chemist and engineer, invented modern concrete in 1818 and published his research as a "gift to humanity".
Later an englishman patented (stole) vicat's discovery in 1824.

@raymondpeters9186 5 months ago

I've been building pumicecrete homes for 30 years

@JazzMoonFly 6 months ago

The concrete in the Coliseum in Rome has resisted time and earthquakes. It was poured almost dry and by hand.

@Greenr0 4 weeks ago

Sadly, not steel bar re-enforced concrete wall over certain height does not pass building inspection because it fails the building code. So, if you want to build a structure like the Roman that will last thousands of years, you will have to build secretly.

@timshort2601 3 months ago

I want to try using this to pour some sidewalk slabs

@francescobellino6515 5 months ago

In Puglia, Italy, an ancient technique was used to waterproof cisterns dug into Cretaceous limestone. The ingredients were hydrated lime and a volcanic ash from the eruption of the Fregrei fields in Naples. My grandfather told me that it had to be mixed vigorously and for a long time. It can still be found in old cisterns. Could this be of interest?

@-htl- 6 months ago

The first reason for failure is that Portland cement is used incorrectly. You see so many people making the standard mistakes. First, the pour must be at least 10 cm thick. Secondly, the reinforcement must be at least 5-10 cm away from each outer surface, 5 cm is in the middle and 5-10 cm from the outside! Never hammer a bar into the ground for reinforcement! When pouring it onto the ground, always pour it onto a plastic layer to prevent water from being sucked out, making it porous and weak. For example do not use 35 kg sack of cement/100Liter (aggregate and sand), but 8-9 kg; 40L of hard aggregate and 35L of sand. Always vibrate it. And most importantly, be economical with adding water. Wet concrete like in this video is much less durable. Water is space that needs to be filled when drying, so too much water makes it weaker and it delutes the clueing. It should be just wet, like mud. Do water it after a couple of hours when it is still wet however does no longer desolve the cement. My concrete is harder than most stone. That's also what you need to understand, the application. Concrete should only be used if the goal is to make it as hard as stone. It doesn't work with soft stone, and the soil must be well compacted.

@Michael-r3n4j 6 months ago

That's great 👍
I remember how we used to talk about this very topic back in the 1970s.
And how corporations replaced things that last with things meant to break down.
They called it "Planned Obsolescence ".
I hated it!

@elefantspidsmus 5 months ago

I regard this YouTube channel as one of the most profound and relevant channels AT ALL! Profound because all the information is thoroughly collected and presented. And relevant because it hits the nail on what exactly went wrong with our modern world and technology. And although your focus is building processes and materials, your analysis is applicable for an analysis of the whole modern culture and its decay over time and the miserable state, we now have reached.

@thehiddencenturies 6 months ago

What would happen if modern infrastructure projects used Roman-style concrete for foundations instead of Portland cement?

@anthonymichaels536 6 months ago

You can make quick lime with shells and a wood fire. Crazy to think we have been one proprietary step away from unlocking this secret.

@lpad9651 6 months ago

Early in the 20th Century, many concrete homes were built, whose surfaces don't show cracking. They included iron pieces or flakes. The idea was, the iron would rust and expand and seal the cracks.

@VectorAntiquity 5 months ago

How easy is it for an everyday person to get proven substitutes like metakaolin or ground pumice if they want to build a foundation that will last?

The idea that concrete can actually grow stronger over time as it reacts with its environment feels like a complete shift from the usual experience of seeing driveways start cracking within just a few years.

@BradleyBellwether-oy2qi 6 months ago

Vitruvius probably wasn't misinterpreted by scholars.
He likey used misinformation because back in those days, knowledge like that was protected tradecraft.
So much was coded or intentionally falsified to mislead.