Wednesday, 22 July 2009

Portland Cement

On the July 12th walk we spent a little while discussing the Rocket House and the possibility that a piece of masonry was made with Portland cement rather than the older lime mortar. I think the Rocket House was built in the 1850’s, but perhaps someone can clarify the date.

So a bit of history: Portland cement was patented by Joseph Aspdin between 1825 and 1828 and was widely manufactured by 1852. Portland cement possessed much greater strength than lime mortar and so became widely used. So much so that Sir Joseph Bazalgette specified that the London sewers, constructed between 1859 – 1866, should be built using it. Incidentally Portland cement has nothing to do with Portland, apart from an aspiration that it should be as strong as Portland stone.

If the Rocket House were built in the 1850’s then it is possible that it used Portland cement.

I have been on three of the walks now and really enjoyed them all. If I find time I'll add something about that, rather than this techy stuff.

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