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Why was Roman concrete so durable?

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Re: Why was Roman concrete so durable?

#221

Post by thowei2i34234 »

Reminds 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 across the world due to birth of religion and its obsession with tyrannical power over everything is such a tragedy on humankind... this was recognized by the thinkers of Europe during the wee end of the 'renaissance', but in light of post-WW2 plebification of intellectuals, is being rolled back because of the current crop's moronic obsession with another religion: Marxism.

Such tragedy. tck. Such tragedy.

Re: Why was Roman concrete so durable?

#222

Post by ithkuil »

tuatoru wrote: post #189
boogoob wrote: post #129

Isn't the particularly short lifespan of modern concrete construction mostly a combination of its use in areas with regular freeze-thaw cycles and using a reinforcement material that rusts (and in doing so expands, damaging more concrete and hastening further water inclusion)?

> Isn't the particularly short lifespan of modern concrete construction mostly a combination of its use in areas with regular freeze-thaw cycles and using a reinforcement material that rusts No. It's a consequence of designing to requirements of minimum cost and a 50-year lifespan. It'd be easy to make concrete with much longer lifespan, but it costs more.

“Any idiot can build a bridge that stands, but it takes an engineer to build a bridge that barely stands.” - Unknown

Re: Why was Roman concrete so durable?

#223

Post by kaesar14 »

thowei2i34234 wrote: post #221

Reminds 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…

What an atheist meme. These things were ‘lost’ because of breakdowns in trade networks caused by breakdowns of central authority and invasions by outside powers. If anything, the Church is what’s kept the Classics alive through its usage of Latin in the clergy and its preservation of Roman structures as churches.

Re: Why was Roman concrete so durable?

#224

Post by ziotom78 »

kaesar14 wrote: post #223
thowei2i34234 wrote: post #221

Reminds 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…

What an atheist meme. These things were ‘lost’ because of breakdowns in trade networks caused by breakdowns of central authority and invasions by outside powers. If anything, the Church is what’s kept the Classics alive through its usage of Latin in the clergy and its preservation of Roman structures as churches.

The Pantheon is a perfect example. It has survived for 2000 years because it was repurposed as a church.

Re: Why was Roman concrete so durable?

#225

Post by rerdavies »

saalweachter wrote: post #152
moloch-hai wrote: post #146

Earlier 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…

I wonder if generational reputations and transmission of methods from master to apprentice is sufficient. "Secundus was an apprentice to Marius who was an apprentice to Darius, who built that awesome aquaduct; Marcus was an apprentice to Felix who who was an apprentice to Marcellus, whose shit bridge fell down after twenty years. We're going to hire Secundus instead of Marcus."

Real Roman engineering theory came from Marcus Vitruviouss Pollio's De Archetectura. Considered to be the ultimate reference text for building and engineering projects in Rome in 32bce, It's ten volumes cover how to build everything from temples, to aqueducts, to water mills to machines used for construction. A fascinating read, if you're curious how Romans built things.

De Architectura provides the sort of long-term perspective required to build and engineer projects that were meant to last for centuries, based on experience gathered from centuries of recorded experience.

I'm not sure if De Architectura is the only book that Roman Architects used. But it was certainly the most important.

Hundreds of pages of De Architectura list dimensions of older ancient buildings, the dimension and spacing of pillars, and failures encountered during or after construction. Something along the following lines (not actual text):

---

The second Temple at Delos was built in 432bce. It consisted of 13 x 29 doric columns, 6' in diameter, 22' high, spaced on 12' intervals, with two rows in the pro-cella. The cella measured ..... The entrance to the cella was 16' high and 12' wide with a granite lintel measuring 16' x 3' x 2'.

The lintel above the entrance cracked and had to be replaced after an earthquake in 430bce. The front-right architrave cracked in 329bce, but was not repaired. The temple was subsequently abandoned and collapsed completely after an earthquake in 327bce.

The temple of Apollo at Thebes ....

The main architrave cracked while it was being mounted, and further construction was abandoned.

---

Given a hundred or so such examples, a Roman architect of a new temple could make somewhat informed decisions about how high, how wide, and how thick he would need to build a new temple, and how afraid he should be when he was commissioned to build a new temple that was higher, wider, or taller.

Re: Why was Roman concrete so durable?

#226

Post by Bayart »

insane_dreamer wrote: post #105
akolbe wrote: post #103

Here 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.

I wonder what percentage of the original stones are left (given that it was repaired and restored over the centuries)

The Pantheon is very notable among Roman monuments for having little done over the years other than cosmetic upgrades.

Re: Why was Roman concrete so durable?

#227

Post by walty »

sporkland wrote: post #216
dima_vm wrote: post #162

Earlier quoted context omitted.

Not always, if rebars are pre-tensioned before concrete solidifies. So the rebar is always under tension. Pretty common in prefab parts, like bridge bars.

For someone totally outside this space I had assumed concrete is rigid and brittle and rebar reinforcement allows for it to bend and flex without breaking. But your comment makes it feel like it keeps the concrete in tension with compression forces to make it sturdier. Can you ELI5 what the rebar does to help?

You're going to love this playlist from Practical Engineering [1]. Grady explains all of this much better than I could. The second video explains reinforcement and the fifth explains pre-stressing.

[1] https://www.youtube.com/watch?v=UOHURuAf5iY&list=PLTZM4MrZKf...

Re: Why was Roman concrete so durable?

#228

Post by pigsty »

ziotom78 wrote: post #224
kaesar14 wrote: post #223

Earlier quoted context omitted.

What an atheist meme. These things were ‘lost’ because of breakdowns in trade networks caused by breakdowns of central authority and invasions by outside powers. If anything, the Church is what’s kept the Classics alive through its usage of Latin in the clergy and its preservation of Roman structures as churches.

The Pantheon is a perfect example. It has survived for 2000 years because it was repurposed as a church.

And lots of other Roman buildings didn’t survive because they were destroyed so the blocks could be repurposed into churches in other locations.

The Parthenon is one (1) building that survived basically as-is while countless others were actively demolished.

One thing that surprised me when visiting Rome is how little original buildings existed. But when you get increasingly far from the city of Rome, you’ll find quite a few well preserved Roman buildings that were out of reach of the long tentacles of the Catholic Church.

Re: Why was Roman concrete so durable?

#229

Post by Animats »

LegitShady wrote: post #101
ogogmad wrote: post #81

For people who don't know the difference between cement, mortar and concrete: Cement is a substance used for producing mortar and concrete. It's never used on its own. It is a "binding agent". Note that the term "cement" is often not used correctly in everyday speech, with people talking about gluing bricks together with cement, when bricks are actually glued together with mortar. Mortar is the glue between bricks. Y…

>There is also reinforced concrete, which the Romans didn't have. While concrete by itself can in principle be moulded into any shape, this can sometimes fall apart, even after hardening. Reinforcement refers to putting a concrete around metal wiring, providing more versatility. Not a correction per se, but some further explanation. The reason for reinforcement is because concrete is strong in compression and weak in…

There's a small trend towards stainless steel rebar. It's expensive, but is now used for concrete structures near salt water.

Epoxy coated rebar turned out to be a mistake. One scrape in the epoxy and it starts rusting. Exposure to UV prior to installation can damage the epoxy coating. Currently banned in Quebec.[1]

[1] https://news.ycombinator.com/item?id=27676447

Re: Why was Roman concrete so durable?

#230

Post by [deleted] »

Maursault wrote: post #213
akolbe wrote: post #103

Here 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.

[deleted]
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