www.bbc.co.uk/news/uk-england-london-19486211
repairs to the road may take up to a week.
The water firm estimated fixing the burst pipe would take two days while it would take up to a week for new concrete to set.
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The romans made concrete that set under water in 48 hours.
Last edited by: VxFan on Wed 5 Sep 12 at 13:54
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how many cars and lorries could drive over it the following day?
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Many a legion could march over it, and many a Roman navis oneraria coul berth and unload at it.
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>> The romans made concrete that set under water in 48 hours.
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They'd probably recognise the pipework and road surface as their own work.
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>> The romans made concrete that set under water in 48 hours.
Horses for courses. It's perfectly possible to make concrete right now that'll set underwater and with accelerated setting too. This is actually easier underwater as the water conducts away the heat generated by the setting process. You have two problems.
1) Fixing the pipe without removing the water is a bit of a bitch.
2) Accelerated setting reduces the final strength of the concrete. You actually want retarded setting in this environment to ensure maximum strength is acheived.
Roman concrete, while very clever of them, was actually rather duff. The secret was that they used Pozzolam (pumice) as the main aggregate component, as most of their concrete structures would have collapsed under their own weight if conventional aggregate were used. Pozzo does not wear well and has little strength in compression. You might well be able to march a legion over it (they didn't, Roman roads were built of sand and aggregate with a block paved surface), but a 40 tonne truck would break it in short order.
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Interesting. Thanks TeeCee.
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>>accelerated setting too. This is actually easier underwater as the water conducts away the
>>heat generated by the setting process.
Really? Accelerated curing is generally done under higher temperatures, not lower (the rate of reaction being higher at higher temperatures). Cure your concrete in the autumn and you'll get a stronger concrete than in the summer (avoid the winter as frost in setting concrete wrecks everything).
So if the water is conducting the heat away, you are surely retarding the curing period, not accelerating it?
And OP, thanks. That changes my journey planning for Friday evening... M1/A1.
Last edited by: Mapmaker on Wed 5 Sep 12 at 14:25
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London North Cirular closed at Brent Cross - Zero
