Scientists explain ancient Rome's long-lasting concrete
Having personally benefitted from Roman engineering, I have long marveled at the skill of Roman engineers.
Ancient sea walls built by the Romans used a concrete made from lime and volcanic ash to bind with rocks. ... Rather than eroding, particularly in the presence of sea water, the material seems to gain strength from the exposure. ... the concrete contained a rare mineral called aluminium tobermorite.
Having personally benefitted from Roman engineering, I have long marveled at the skill of Roman engineers.