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Have they ever figured out how the Romans made concrete and got away with not using rebar ???.

hguant 5y ago
Yes - basically, high quantities of volcanic ash act as a much stronger binder than is currently used/available now, and the chemistry of the cement they used meant that as it aged it got stronger. Tangentially - it's not that we can't make concrete that way, it's that for many structures we're building of concrete, building to last 100+ years is over kill, and would increase costs drastically for a building or structure that will most likely be torn down before it reaches its life expectancy.
joatmon-snoo 5y ago
Yes, the research came out a few years ago: https://pubs.geoscienceworld.org/msa/ammin/article/102/7/1435/353606/Phillipsite-and-Al-tobermorite-mineral-cements https://pubs.geoscienceworld.org/msa/ammin/article/102/7/143... tl;dr: we took a long time to realize that the Romans didn't use potable water, they used saltwater; the volcanic ash they had access to was also very important
jandrese 5y ago
My making the walls incredibly thick, not having large overhangs, and having the foresight to build an empire in a seismically dead area.
- pmontra 5y ago
  Rome is a moderately seismic area suffering from amplification of seismic waves from earthquakes in the more seismic areas in the mountains. Basically all of Italy is seismic. Part of the Colosseum was destroyed by an earthquake in 1349. The google translation of this Italian page is quite good at explaining what happened https://www.focus.it/cultura/storia/perche-il-colosseo-e-crollato-per-meta https://www.focus.it/cultura/storia/perche-il-colosseo-e-cro... TLDR, the asymmetrical 4-2 storeys shape is the result of that earthquake when the top of the part of the building built on softer ground felt down.
coryrc 5y ago
They only used the arch, so everything was in compression. Rebar gives concrete tensile strength.

Yes - basically, high quantities of volcanic ash act as a much stronger binder than is currently used/available now, and the chemistry of the cement they used meant that as it aged it got stronger. Tangentially - it's not that we can't make concrete that way, it's that for many structures we're building of concrete, building to last 100+ years is over kill, and would increase costs drastically for a building or structure that will most likely be torn down before it reaches its life expectancy.

joatmon-snoo 5y ago

Yes, the research came out a few years ago: https://pubs.geoscienceworld.org/msa/ammin/article/102/7/1435/353606/Phillipsite-and-Al-tobermorite-mineral-cements https://pubs.geoscienceworld.org/msa/ammin/article/102/7/143... tl;dr: we took a long time to realize that the Romans didn't use potable water, they used saltwater; the volcanic ash they had access to was also very important

jandrese 5y ago

My making the walls incredibly thick, not having large overhangs, and having the foresight to build an empire in a seismically dead area.

pmontra 5y ago
Rome is a moderately seismic area suffering from amplification of seismic waves from earthquakes in the more seismic areas in the mountains. Basically all of Italy is seismic. Part of the Colosseum was destroyed by an earthquake in 1349. The google translation of this Italian page is quite good at explaining what happened https://www.focus.it/cultura/storia/perche-il-colosseo-e-crollato-per-meta https://www.focus.it/cultura/storia/perche-il-colosseo-e-cro... TLDR, the asymmetrical 4-2 storeys shape is the result of that earthquake when the top of the part of the building built on softer ground felt down.

coryrc 5y ago

They only used the arch, so everything was in compression. Rebar gives concrete tensile strength.