Roman concrete
Volcanic ash and lime make a material that sets underwater and lasts two thousand years.
- When
- —
- Duration
- 325 years
- Known to
- ± 50 years
- Era
- Classical, Holocene
Roman builders combine lime with volcanic pozzolana to produce a concrete that cures in water and grows stronger over time — recent work shows lime clasts in the mix allow it to self-heal cracks. It makes possible vaults, domes and harbours on a scale masonry cannot reach. The Pantheon's unreinforced concrete dome, finished around 126 CE and 43 metres across, is still the largest of its kind in the world.