One hundred and eighty-two years ago today, a British inventor named Joseph Aspdin patented a process for making Portland cement. He called the product "Portland" because its color resembled that of Portland limestone, a sedimentary rock quarried from the Isle of Portland in the English Channel. Aspdin's process burned finely-ground chalk and finely-divided clay in a lime kiln until the carbon dioxide was removed. The sintered powder was then combined with water to produce hydraulic cement. Sand and gravel could be added to form concrete. Today, Portland cement accounts for 95% of all the cement produced. Civil engineering projects such as the Pentagon and the Eisenhower Interstate Highway System owe much to Joseph Aspdin.
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.
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An elephant is a mouse built to government specifications.
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.
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An elephant is a mouse built to government specifications.
Re: October 21, 1824: Patenting Portland Cement
