Roman concrete would be a strong contender:
https://en.wikipedia.org/wiki/Roman_concrete
That stuff is clearly better than our modern concrete.
In theory one could replicate that material but nobody does, hence our crumbling bridges.
https://en.wikipedia.org/wiki/Roman_concrete
That stuff is clearly better than our modern concrete.
In theory one could replicate that material but nobody does, hence our crumbling bridges.
One of the reasons modern concrete fails is because steel reenforcement, as it corrodes and expands inside structures. Ancient buildings such as the Pantheon rely on compressive strength for support, so they last much longer. We could build building in this way, but it uses a lot of material and would be prohibitively expensive; especially since most building are not long term investments.