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.
Our newer concrete is better for the goals we are setting in construction, which does not tend to include permanence. Our goals are mostly about strength to weight ratios and other properties that allow for massive numbers of floors with and as little mass as possible with reliability measured in decades. Basically guaranteed to last reliably with minimal upkeep.
We are continuously practicing new ways to build with concrete, wtf are you talking about?