October 21, 1824: Patenting Portland Cement

Joseph Aspdin was really re-inventing the wheel. The Romans had something almost identical to portland cement, call concretia if I remember correctly, that they made using the ash from a certain volcano some 1800 years earlier. Since the Romans stole most of their technology its probably a lot older than that an they got it by over running some the society or the poor shmucks that actually invented it.

Not quite, the pozzolana base differs from the way portland cement is made.

http://en.wikipedia.org/wiki/Pozzolana

http://matse1.mse.uiuc.edu/concrete/hist.html

True Portland cement is an industrially produced version of naturally occurring pozzolana cement and from what I read they are pretty close to the same thing. I would be interesting to know how much Joseph Aspdin knew of pozzolana cement or whether it just a very slow case of deja vu.