And we use rebar because we like long, flat bridging spans that can hold hundreds of tons at a time — something Roman concrete has no hope of ever doing, unreinforced.
Not necessarily countering your point, but perhaps giving some perspective.
The City I grew in (Cordoba) has a roman bridge[1], originally built 1st century BC and still standing. It supported a 2-way street until 2004, when it was pedestrianised.
Caveats:
* It has gone over a great deal of renovations/partial rebuilds on its history, so its durability can not really be attributed to roman concrete alone. Only 2 of the original 16 arcades remain. One could argue that "it's not the same bridge" any more (Theseus' Bridge).
* I ignore wether they used concrete to build the original one. I'm not an architect. For all I know, the initial construction could have been mortarless stone, and cement (as well as reinforcement) could have been added in some of the later renovations.
That said, all bridges require periodical servicing/renovations anyway, in order to remain functional. And this one has stand for 2000 years.
Rebar reinforced concrete fails, I assume, because the rebar rusts? If so, isn’t the issue greatly reduced (potentially) if we were to use the quicklime process of the Romans? If the self-healing prevents water penetration, does that stop rebar from rusting?
Remember that roman concrete often used iron for reinforcement. The Colosseum is a famous example of this. The only reason it's not still there today is because metal, particularly iron, was extremely valuable so after the fall of the Roman empire, people tore whatever iron they could out of the structure (akin to people today stealing wiring and copper piping from the walls of houses).
thechao|2 years ago
otikik|2 years ago
The City I grew in (Cordoba) has a roman bridge[1], originally built 1st century BC and still standing. It supported a 2-way street until 2004, when it was pedestrianised.
Caveats:
* It has gone over a great deal of renovations/partial rebuilds on its history, so its durability can not really be attributed to roman concrete alone. Only 2 of the original 16 arcades remain. One could argue that "it's not the same bridge" any more (Theseus' Bridge).
* I ignore wether they used concrete to build the original one. I'm not an architect. For all I know, the initial construction could have been mortarless stone, and cement (as well as reinforcement) could have been added in some of the later renovations.
That said, all bridges require periodical servicing/renovations anyway, in order to remain functional. And this one has stand for 2000 years.
[1] https://en.wikipedia.org/wiki/Roman_bridge_of_C%C3%B3rdoba
lll-o-lll|2 years ago
AlbertCory|2 years ago
redandblack|2 years ago
jacoblambda|2 years ago