A 1700-yr old mystery possibly solved!

[Gaolee]

Burrata? Ricotta? Something else?

-Mike

Probably Pecorino Romano, but that's a part of the study I didn't read carefully.

 

[fdeck]

There's certainly room to improve concrete. There are scientists and engineers devoting entire careers to the study of concrete.

One misunderstanding of concrete is that the reinforcement doesn't just strengthen it. The Roman structures shown in pictures are all based on the compression strength of concrete, but concrete has very poor tensile strength. This means structures have to be simple and stout, like bridges supported by heavy arches. Adding reinforcement in the form of steel bars or other materials results in a composite with high compression and tensile strength, allowing structures to be much lighter. The results are visible in road bridge spans and skyscrapers. Prior to the steel age, there were practically no habitable buildings taller than a few stories. Steel and concrete also work together in tall buildings to stabilize the steel and prevent it from catching on fire.

Roman concrete cannot, by itself, satisfy our needs. And we can't just make more of it to reduce the need for reinforcement, because cement production is a major greenhouse emitter.

 

[Michael Jewels]

A very interesting thread.

One of my uncles was a bricklayer for 50 years, and he never mentioned any of this.

Then again, he was a bricklayer, not interested in history.

Thank you for this thread, MoireBass.

Now, if we can only rediscover the formula for Greek Fire!

Mike

 

[Hot Rats]

The Hoover Dam is close to 80 years old. How is it that concrete is still viable?

 

[Alkali Ike]

 

[Gaolee]

The Hoover Dam is close to 80 years old. How is it that concrete is still viable?

It hasn't fully cured. It still needs cooling inside. But it may be eroding in areas. I don't know. Same with a number of other dams.

 

[Jeff Scott]

The Hoover Dam is close to 80 years old. How is it that concrete is still viable?

I have no idea, but it was a blast to get to tour the dam all through it, outside and in, back in 1974.

 

[kesslari]

That's very cool and interesting.

 

[fdeck]

It hasn't fully cured. It still needs cooling inside. But it may be eroding in areas. I don't know. Same with a number of other dams.

It'll dry up before it falls over.

 

[Old Fart]

Don't believe everything you read. Sure, crappy concrete mixes and applications fail WAY more quickly than hotter mixes properly placed and finished. Today's civil projects, at least in my state, incorporate very strong and durable concrete mixes. Of various types and formulations, for different applications. Our modern civil engineers are not idiots. Those mixes harden increasingly for at least 80 years before the hardening process stops.

Concrete's claim to fame is its compressive strength but it has poor tensile strength which is why steel is added. Most civil project rebar is epoxy-coated.

Lime is used in all concrete, not just ancient Roman concrete. Limestone and clay is heated in a kiln to make Portland Cement, the active ingredient in concrete.

 

[gln1955]

It hasn't fully cured. It still needs cooling inside. But it may be eroding in areas. I don't know. Same with a number of other dams.

I toured it in 2019. There are leaks into the interior in places. Nothing major....yet.

 

[Gaolee]

I toured it in 2019. There are leaks into the interior in places. Nothing major....yet.

Well, there you have it. Too bad it wasn't built with Roman concrete.

 

[Gaolee]

Don't believe everything you read. Sure, crappy concrete mixes and applications fail WAY more quickly than hotter mixes properly placed and finished. Today's civil projects, at least in my state, incorporate very strong and durable concrete mixes. Of various types and formulations, for different applications. Our modern civil engineers are not idiots. Those mixes harden increasingly for at least 80 years before the hardening process stops.

Concrete's claim to fame is its compressive strength but it has poor tensile strength which is why steel is added. Most civil project rebar is epoxy-coated.

Lime is used in all concrete, not just ancient Roman concrete. Limestone and clay is heated in a kiln to make Portland Cement, the active ingredient in concrete.

Good to know about the 80 year hardening process. I always used 40 years as the rule of thumb. That's probably still accurate for most of the concrete that gets poured.

 

[RichterScale]

I toured it in 2019. There are leaks into the interior in places. Nothing major....yet.

If I were them, I'd run to depot and grab a few tubes of this before it gets worse.

 

[gln1955]

If I were them, I'd run to depot and grab a few tubes of this before it gets worse.
View attachment 4955070

And plenty of these.

[Invalid or Expired Link Removed]
They have an extensive seismic monitoring system, too.

 

[Tom Bomb]

If they try to sell you one of these, don't buy it, dam it.​

​

 

[Michael Jewels]

Don't believe everything you read. Sure, crappy concrete mixes and applications fail WAY more quickly than hotter mixes properly placed and finished. Today's civil projects, at least in my state, incorporate very strong and durable concrete mixes. Of various types and formulations, for different applications. Our modern civil engineers are not idiots. Those mixes harden increasingly for at least 80 years before the hardening process stops.

Concrete's claim to fame is its compressive strength but it has poor tensile strength which is why steel is added. Most civil project rebar is epoxy-coated.

Lime is used in all concrete, not just ancient Roman concrete. Limestone and clay is heated in a kiln to make Portland Cement, the active ingredient in concrete.

Very good post, Old Fart.

My bricklayer Uncle used to talk like you.

He passed in 1984.

I still miss him.

Mike

 

[DirtDog]

Modern concrete doesn’t contain the bones of Roman slaves.

 

[Gaolee]

And plenty of these.

[Invalid or Expired Link Removed]
They have an extensive seismic monitoring system, too.

No worries. The Colorado River will dry up and there won't be anything pushing on that dam in another few years. All those Las Vegas golf courses and Sacramento rice paddies will be out of luck.

 

[Pilgrim]

I remember that they are working on commercial applications. If the Roman version sets faster than our current stuff, it would seem that there might be a mix/delivery time issue to get it to the work site and pour quickly enough.