I’ve just started another MOOC, a massive open on-line course; these MOOCs are amazing, absolutely free and cover such diverse subjects from the best universities in the world.One of my interests is archaeology and I have done three archaeological MOOCs, Archaeology’s Dirty Little secrets from Brown University, Shipwrecks and Submerged Worlds from Southampton University, and Hadrian’s Wall, Life on the Roman Frontier from Newcastle University. I am not particularity interested in the Roman period, but the course on the Wall was fascinating, and the marine-archaeology was absolutely brilliant – in fact it was so brilliant that when I saw Southampton University had another course I signed up straight away, so I am now studying The Archaeology of Portus. Portus was a massive port and harbour established by the Emperor Claudius to serve Rome.
We are only on the first week and already I am enjoying the videos, articles and extra material! There was a link to a page about concrete… now concrete is very useful, a very, useful material. I know that, and I know it is used for all sorts of different types of building projects and that it is sometimes reinforced with iron to become reinforced concrete… and I know it is made from cement… and I know cement is what amounts to a glue… but I had never ever given concrete any thought whatsoever.
The Romans used concrete… I don’t think I knew that, but if you think about it, they must have done to do the amount of building work and construction that they did. One of the great advantages when constructing ports and harbours, as they did at Portus, was that concrete will set under water. Our modern concrete is made in the same way as the Romans did nearly two thousand years ago, combining three basic materials… stuff, gluing stuff and water. By stuff I mean aggregate which is something like gravel, or very small lumps of stone or rubble, or even broken bricks, and the gluing stuff, cement or mud or other agents.The Romans had a particular sort of binding agent, pozzolona, which was made from volcanic material.
In Roman times, the same as today, concrete is not always the most attractive of materials whatever its other excellent qualities, and we, like the Romans, disguise it, using facing materials, such as attractive bricks, marble, tufa,or tiles, or mosaics… but beneath the fine exterior would be concrete, strong, durable concrete.
Lois Elsden 