TIL Roman concrete was way stronger than modern stuff

I was reading a random article while waiting for a keg to tap at work last night, and it mentioned Roman concrete actually gets stronger over time when exposed to seawater. I always figured old tech was just primitive and we've improved everything since. Turns out they used volcanic ash and lime in ways that create a mineral called aluminum tobermorite that forms after decades in salt water. Has anyone else run across other ancient building tricks that beat modern methods?

3 comments

3 Comments

wilson.joseph1mo ago

Honestly that Roman concrete thing blew my mind too when I first heard about it. Ngl I spent like an hour down a YouTube rabbit hole watching some guy explain how the seawater reacts with the volcanic ash over centuries. Tbh it makes you wonder what other old building tricks got lost to time. My buddy who works in construction said they still use a version of the hot mixing method the Romans used for some specialty jobs. Crazy how something from two thousand years ago can still teach us stuff today.

lee8471mo ago

My uncle was a mason for 40 years and he used to go on rants about how modern concrete is basically garbage compared to what the Romans did. He said they found some Roman harbor blocks that were over 2,000 years old and still stronger than the stuff they pour today for bridges. He actually tried making a batch using his own mix of volcanic ash from a landscaping supply place near his house. The whole thing set so hard he had to rent a jackhammer to break up the leftover pile in his driveway. Still cracks me up thinking about him cussing out a block of cement in his backyard.

elizabethmason1mo ago

Wait, so does that mean Roman underwater structures are basically immortal or something? @wilson.joseph your buddy's hot mixing comment reminded me of how blacksmiths still use some old techniques because modern steel just doesn't hold up the same way. I swear every time I dig into ancient tech I find something that blows my mind.