Earlier quoted context omitted.
> Not bad for something built nearly 2,000 years ago. According to the Pyramids, Stonehenge, Newgrange, Watson Brake, et al., it's a little premature to suggest that. Let's check back in 3,000 years.
stone != concrete edit: we have a > 2,000 years old pyramid in Rome too, and it's in perfect shape, because stone != concrete https://upload.wikimedia.org/wikipedia/commons/thumb/9/9d/Ci...
Why was Roman concrete so durable?
271–280 of 299 posts
Re: Why was Roman concrete so durable?
#272Reminds me of the Wootz Steelmaking (and much else) in classical India which was lost during the period of Anglo-Islamic colonization. Roman empire, Egypt and Greece, IMO is, contrary to current myths, is far closer in spirit to India than to anything of the 'modern West'. Indeed, the Greeks ruled parts of India for many centuries, and Rome had a great amount of trade with it. The loss of so much rich tradition acros…
Wootz steel was never lost. Just the contaminated with vanadium ores they used disappeared. We know quite well what happens to a carbon steel with vanadium. Most high performance steels today are made with it in the alloy.
Re: Why was Roman concrete so durable?
#273Here is a nice picture of the Pantheon, mentioned in the article as a prime example of these incredibly durable Roman concrete structures: https://commons.wikimedia.org/wiki/File:Pantheon11111.jpg#/m... Not bad for something built nearly 2,000 years ago.
> Not bad for something built nearly 2,000 years ago. According to the Pyramids, Stonehenge, Newgrange, Watson Brake, et al., it's a little premature to suggest that. Let's check back in 3,000 years.
The pyramids are essentially just piles of rocks. The impressive part about them is not really how they stood out the test of time, in fact they lost most of their finer details, but how an ancient civilization managed to make piles of rocks that big.
The Pantheon is not a pile of rocks, it is made of engineered materials (concrete), with domes and overhangs. Unlike "pile of rocks" architecture that essentially can't fail, if it wasn't well engineered, it would have collapsed into something unrecognizable.
Re: Why was Roman concrete so durable?
#274Relevant thread: https://twitter.com/cleptok/status/1611622181665923075 Ok. Let's do a short thread on Roman cement for the 3 people out there that might be interested. You often hear that the Romans had some sort of superior and arcane knowledge on superior cement mixes that has been now lost. And still today we cannot replicate it. This is complete nonsense. Modern day cement (and any other building material, reall…
That reads as somewhat misguided and dismissive. You don't have to understand the chemistry to improve recipes by trial and error, over multiple generations, and learn from the still-standing structures.
And there is still value in studying today those that survived in order to improve ours. The way lime healed cracks is new to me at least, but it's taken as a given here.
> you wouldn't build anything worthwhile
You just need more cement, it could be replaced with fibers. We still use unreinforced concrete in some cases.
Re: Why was Roman concrete so durable?
#275Earlier quoted context omitted.
It's also useful if you want to do concrete demolition yourself using only hand tools. You drill holes, pour, wait for cracks, and then use a pick and hammer to remove the remaining chunks. Often sold as "expansive grout".
If you can drill holes you can use stone splitting wedges. A lot of these high dollar modern miracles of chemical engineering are purely for use in situations where it's cheaper to just buy the $100/tube stuff than it is to try and get the approval to do something sensible. Basically you're paying to get around process tech debt.
Not in a refinery, or you have to buy weird/expensive non-sparking hammers and wedges. Aluminum bronze wedges are commercially available but the liability insurance is incredible so you're better off cutting your own (its a wedge, not a rocket engine...). It ends up being cheaper to use the expansive grout.
Re: Why was Roman concrete so durable?
#276Re: Why was Roman concrete so durable?
#277Earlier quoted context omitted.
Right. Romans experimented with the formula for concrete for centuries, and learned a lot about how centuries-old concrete structures deteriorated. They didn't have modern chemistry, but they had observational skills and were serious about their work. It would not be surprising to find that most structures weren't built to last any longer than ours, but that some were meant for the ages. An important difference today…
We build dams to be long lasting.
More of them, anyway, than of other types. Some have not lasted, with typically regretted consequences.
Re: Why was Roman concrete so durable?
#278Earlier quoted context omitted.
In Europe, 100km is a long way; in the US, 100 years is a long time.
Do you mean 1000km? The thread is about Rome being easy to reach.
It's just a saying, having the same number on both ends (but measuring different things) is the part that is supposed to make you think it's clever ;)
Re: Why was Roman concrete so durable?
#279Earlier quoted context omitted.
The problem with making people slow down is that it slows people down.
Sometimes that's what's needed. https://en.wikipedia.org/wiki/Braess%27s_paradox
But usually, it slows people down.
> In 2012, Paul Lecroart, of the institute of planning and development of the Île-de-France, wrote that "Despite initial fears, the removal of main roads does not cause deterioration of traffic conditions beyond the starting adjustments. The traffic transfer are limited and below expectations".[4] He also notes that some private vehicle trips (and related economic activity) are not transferred to public transport and simply disappear ("evaporate").[4]
> The same phenomenon was also observed when road closing was not part of an urban project but the consequence of an accident. In 2012 in Rouen, a bridge was destroyed by fire. Over the next two years, other bridges were used more, but the total number of cars crossing bridges was reduced.[4]
It seems a lot like the real-world examples of the phenomenon look like close cousins of "if you remove the smallest values in a set, the average goes up".
Re: Why was Roman concrete so durable?
#280Earlier quoted context omitted.
If you can drill holes you can use stone splitting wedges. A lot of these high dollar modern miracles of chemical engineering are purely for use in situations where it's cheaper to just buy the $100/tube stuff than it is to try and get the approval to do something sensible. Basically you're paying to get around process tech debt.
Not in a refinery, or you have to buy weird/expensive non-sparking hammers and wedges. Aluminum bronze wedges are commercially available but the liability insurance is incredible so you're better off cutting your own (its a wedge, not a rocket engine...). It ends up being cheaper to use the expansive grout.
This is exactly what I mean by "paying to get around process tech debt"
Facility has a "no sparks" in buildings A, B and C rule. Rule obviously doesn't apply to contractors doing a ton of welding during a holiday shutdown. Non-contractors in maintenance dept want to fix some other crap at the same time. Sure they could try and get approval to use a jackhammer concurrent with the other work but in reality there's a 75% chance the safety department will intentionally stonewall until after the shutdown rather than set the precedent of a sensible exemption and the maintenance manager knows it so they buy the expensive grout.