The concrete dome of the Pantheon in Rome remains stable enough for visitors to walk beneath, and some Roman harbours have underwater concrete elements that have not been repaired for two millennia – even though they are in regions often shaken by earthquakes.
Whence this remarkable resilience of Roman concrete architecture? It’s all down to the chemistry.
We mostly know how they made theirs, and could make our own version of it, but we optimize for different things.
The Romans optimized for “that’s cement and it works well”, because they didn’t have anything close to the level of chemical understanding we do now.
We optimize for strength and predictability. Ours can hold a higher load and will likely need repairing about when we predict.
Roman concrete can sometimes, in certain circumstances and with variable effectiveness, repair certain types of damage by chemically interacting with the environment. So maybe it crumbles in a decade or maybe it lasts a millennium.
Article basically points at some researchers who are looking to see if they can bring that healing capability to modern concrete in a predictable and more versatile fashion.
It’s basically the self healing properties of Roman concrete that I find fascinating.
Oh, it’s definitely interesting.
I think people here just got rubbed the wrong way because these articles often make it seem like Roman concrete is better than ours, rather than “look what they accidentally did occasionally”.
We can make self healing concrete today, we just usually opt not to, because the downsides or unpredictable nature makes it unsuitable for the significant cost increase.
The phrase “the bridge is infested with bacterial spore colonies” isn’t one that makes engineers happy.
Yeah, I think people got rubbed the wrong way only from the title. I don’t think they bothered to read it. I don’t think the article in any way emphasised that Roman concrete is better than modern; rather it talked about findings of certain researchers. It was the chemistry which I found interesting.
Agreed. The article doesn’t really make Roman concrete sound great, it even mentions how limited in availability the volcanic ash they used was.
If we wanted to build to last longer, I imagine not using iron-based reinforcement would get us most of the way there, especially where ice isn’t a concern.