• Thread starter The Burgher of TO
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philofra said:
I learned today that concrete reaches its final strength in a 100 years. So each year that passes concrete gets stronger, for a hundred years.
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Thats a myth..20-30 years maybe.

Curing
In all but the least critical applications, care needs to be taken to properly cure concrete, to achieve best strength and hardness. This happens after the concrete has been placed. Cement requires a moist, controlled environment to gain strength and harden fully. The cement paste hardens over time, initially setting and becoming rigid though very weak and gaining in strength in the weeks following. In around 3 weeks, typically over 90% of the final strength is reached, though strengthening may continue for decades
 
It sounds like the curing of concrete is a vague thing, about how long it takes to reach it peak.
 
It's not vague at all, it's just that it's logarithmic and that tends to confuse a lot of people. Strictly speaking it never really stops curing, but it's a matter of someone arbitrarily drawing a line where we say that it's cured 'enough'.

In real terms the stuff the Romans built is still curing today, albeit it isn't curing to a terribly significant degree day-to-day.
 
Pics taken July 28, 2011


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In the picture above there is a white generator, in the left of the photo. It weighs 12,000 lb. I saw the crane lift it up to the ramp to be towed away.

The crane is made in Germany and is forty years old. It is exceptional. The new cranes are made in South Korea and can't lift such heave weights. They also break down more often.
 
All new cranes are made in South Korea? Liebherr isn't building in Germany any longer? New cranes can't lift as much as old cranes? Really?

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philofra said:
In the picture above there is a white generator, in the left of the photo. It weighs 12,000 lb. I saw the crane lift it up to the ramp to be towed away.

The crane is made in Germany and is forty years old. It is exceptional. The new cranes are made in South Korea and can't lift such heave weights. They also break down more often.
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amazing that such an old piece of machinery can stand the test of time and outdo the newer models
 
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