Volcanic ash may have preserved Roman ruins (Good cement)

Discovery ^ | May 13, 2009 | Rossella Lorenzi

[decimon]

Sandy ash produced by a volcano that erupted 456,000 years ago might have helped a huge ancient Roman complex survive intact for nearly 2,000 years despite three earthquakes, according to research presented last week in Rome.

X-ray analysis of a wall sample from the Trajan's Market ruins in Rome showed that the mortars used by ancient Romans contained stratlingite, a mineral known to strengthen modern cements.

"It is the first time that stratlingite is recognized in ancient mortars," Lucrezia Ungaro, the Trajan Forum archaeological chief, told Discovery News. "This is amazing, and shows the technical expertise of Roman builders."

[decimon]

Pozzo ping.

[DemforBush]

“It is the first time that stratlingite is recognized in ancient mortars,” Lucrezia Ungaro, the Trajan Forum archaeological chief”

??????

My Roman history professor told me years ago that one of the secrets to the durability of the roads the Romans built was the inclusion of volcanic ash in the mortar used to hold the stones in the fossa in place.

Maybe it was still just a theory then (instead of a proven fact), though.

[decimon]

Beats me. Maybe “pozzolanic volcanic ash” is special.

[agere_contra]

I bet the Romans would have built the “Big Dig” in two weeks, and none of it would have fallen off and crushed people.

[agere_contra]

I am going to try and use the word “pozzolanic” in a conversation today.

[Jimmy Valentine]

You are right. It was only after people discovered the Romans did this that modern cement started using it too. Another secret of technology lost and then rediscovered.

Ever wonder at the scope of knowledge lost when the Library of Alexandria burned?

[decimon]

I am going to try and use the word “pozzolanic” in a conversation today.

pozzo: well, shaft, pit

pozzo nero: cesspit - "I'm sick of working in this pozzo nero!"

[Adder]

No...its been known for years.

I, too, heard about it.

Big difference is that they didn’t know WHY it worked but that it did work. And it was discovered through trial and error.
The admonition to use the crackly stuff is a give away.

As a general statement, I have noticed that we have collectively seemed to have forgotten all we once knew. This article has a gollygeewhiz tone that I find at once fascinating and repulsive in its ignorance.

Or I am missing something.

[decimon]

I bet the Romans would have built the “Big Dig” in two weeks, and none of it would have fallen off and crushed people.

Of course there would be no crushed people. The lions like their meat fresh.

[John Valentine]

Truth be told, today’s “portland cement” is inferior in several ways to many ancient cements, some used by the romans, others by the Egyptians.

Some of the ways portland cement is inferior: shorter life, excessive heat of hydration leading to cracking and the need to control the same, slow development of ultimate strength, low resistance to deterioration under high heat (like in fires), energy intensive mnufacturing, and inferior dimensional stability.

Yet, most folks assume that today’s technology is automatically superior. In the case of portland cement, the reason it is used almost exclusively in lieu of other, much better cements is simple: building codes.

[Sacajaweau]

Maybe this "stratlingite" is just another name for a recognized component.

I have an old book on the Canals of NY. During the early construction, there was a lawsuit here regarding a patent on "cement" and I believe the comparison was specifically made to Roman Concrete.

[afraidfortherepublic]

A professor at UWM (Milwaukee) published a study about 20 years ago on how to improve the longevity of our roads — add fly ash to them. Fly ash is the residue from burning coal and is cheap and redily available.

Problem?

Our road builders (who run this state) do not WANT to make the roads last longer. Repaving every 5 years provides employment that would be lost if our roads lasted 30 years.

[RipSawyer]

As a general statement, I have noticed that we have collectively seemed to have forgotten all we once knew.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

Yep, I fear that we will see a time when we will need some of the knowledge that used to be so common but has been considered useless for the past two generations.

[TexasRepublic]

As manufacturing in the US continues to be exported overseas, industrial processes will be slowly forgotten as workers retire or die off. The documentation of defunct companies is eventually destroyed. There is no way we could re-industrialize quickly if countries like China decided to stop selling to us.

[RipSawyer]

There is no way we could re-industrialize quickly if countries like China decided to stop selling to us.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

And there is no way we could return to old-fashioned subsistence and live as our great grandparents did either. I still remember some of what I learned growing up but my parents generation (born 1913 and 1916) were some of the last who knew how to take a few simple tools and seeds and survive the old way. There are books that preserve most of it but a family would starve long before they figured out how to put it into practice. For better or worse we are dependent on industry and industrialized agriculture.

[SunkenCiv]

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[calex59]

Are these guys behind or what? Roman cement has been known for decades to be superior to all other forms of cement in that time period and for centuries after. It took hundreds, if not thousands, of years for the EU civilizations to duplicate the Roman type of cement. It was the only cement of its time and, as I said, for centuries after, to be able to dry while under water, it was in most ways similar to modern cement. They may have been murderous jerks but the Romans were great engineers.

[decimon]

They may have been murderous jerks...

But probably no more so than others.

[bert]

Is this what you were alludung to? We still use it today to improve the workability of concrete

Description
Pozzolith 100 XR is a readyto-
use liquid admixture for
producing more uniform and
predictable quality concrete.
Placing and finishing
requirements are facilitated
because this admixture retards
setting time. Pozzolith 100 XR
admixture meets ASTM C 494
requirements for Type B,
retarding, and Type D, waterreducing
and retarding,
admixtures.