1Today we turn to ancient engineering, focusing on why Roman concrete still survives.
2Modern concrete often crumbles within decades, yet Roman harbours have lasted two thousand years.
3For a long time, researchers believed the secret lay simply in the volcanic ash.
4That explanation was accepted for decades, though recent analysis tells a richer story.
5Samples from a harbour near Naples revealed unusual mineral growth inside the concrete.
6Seawater, instead of weakening the material, actually triggered new crystals to form.
7These crystals fill cracks as they appear, giving the structure a self-healing quality.
8The team initially dated the reaction to the construction phase, but later tests disagreed.
9In fact, the healing process continues whenever seawater seeps into fresh cracks.
10Engineers today are experimenting with similar recipes for modern marine structures and seawalls.
11So the Romans were not primitive builders but sophisticated chemists without knowing it.