Pyramid Stones Were Poured, Not Quarried

brian0918 writes "Times Online is reporting that French and American researchers have discovered that the stones on the higher levels of the great pyramids of Egypt were built with concrete. From the article: 'Until recently it was hard for geologists to distinguish between natural limestone and the kind that would have been made by reconstituting liquefied lime.' They found 'traces of a rapid chemical reaction which did not allow natural crystallization. The reaction would be inexplicable if the stones were quarried, but perfectly comprehensible if one accepts that they were cast like concrete.'"

Comments

(obligatory grains of salt)

[mmell]

Question 1: Is the activity of casting liquified lime depicted on any pictographs/heiroglyphics in Egypt? The ancient Egyptians had a marvellous habit of recording a great many things on very durable media - including how their own technology worked. I would expect to find depictions somewhere of Egyptians or their slaves engaged in the tasks of manufacturing and pouring concrete.

Question 2: Is there evidence that the Egyptians used this technology elsewhere? I find it difficult to believe that they would've evolved this kind of technology (concrete) and used it exclusively for the task of pyramid-building.

2nd time I've heard this

[jbeaupre]

The first time was when a researcher about 10 years ago (give or take 10) claimed they were poured because he found a human hair embedded in one.

That's cement, not concrete

[Beryllium Sphere(tm)]

There's no mention of aggregate, the sand and gravel that cement glues together to make concrete.

Re:Casting Vs Forming

[eldavojohn]

Or the Romans tried many times before creating Bath's and Aqueducts.

There's a lot of stuff out there that I can grind up and mold. It will last a day. It will last two days. It will last the week and it might even last the season. But when you come to a place of sand and you see these pyramids that have weathered the elements and retained a decent shape for possibly thousands of years, you might say, "What have you got there?"

I'm not keen on Roman/Egyptian history but I think that the Egyptian society and race are a bit older than the Romans. Wikipedia tells me that the Egyptian empire ran some 7,000 years while the Roman Empire technically only lasted only from 44 BC to AD 476. Ok so in 500 years, how many experiments with possible mixtures could you test. You can test for hardness & solubility on the fly but not duration. If you mix limestone with gypsum, you come up with something like drywall that won't last long at all in the elements. but might initially have a very hard composure.

Go look at some of the adobe structures that have lasted for hundreds upon hundreds of years in the Southwest of the United States. They were using the most abundant resource that was known to last the longest. R&D for the Romans was probably pretty high quality but I was just speculating that nothing then could match 7,000 years of research for something that would bring your leader's through the ages.

It was just speculation on my part but I highly doubt the Romans were the sole originators of the formula for the aqueducts. It really is too bad Alexandria was burned. If I could undo one thing in history, I would be tempted to pick that one.

Why quarry granite then

[vtcodger]

If the Egyptians knew how to form and pour concrete, why on Earth would they drag huge blocks of limestone and granite around to build the rest of the structure? (Maybe Union rules negotiated by the Lower Nile chapter of the Amalgamated Pyramid Craftsmen?) Why not make the whole structure out of concrete? And where are the form marks -- the marks from the boards or whatever that were used to make the form for each block? Granted they'd probably be weathered off from the exposed surfaces, but they should still be there on protected surfaces.

Not the first time

[edwardpickman]

I've heard this theory before but from what I know the mix they are talking about it isn't nearly as strong as regular limestone. The slower crytalization pattern of natural limestone gives it the strength. I question that artifical limestone would be strong enough for even the top layers of a structure that big. Pure limestone isn't concrete. They aren't talking about concrete, that would be obvious if used, they are talking about reclaimed limestone. There are a lot of problems with that theory. Not the least of which is how would the eygptians make that much lime for the stone? You have to heat the lime dust to a very high temperature to break the chemical bonds. It wouldn't be a small undertaking on it's own and would take huge amounts of energy, charcoal essentially. Wood was scarce. There is no other evidence that they made lime concrete so I have serious doubts.

Mortar

[kaoshin]

I always thought that the mortar used was more amazing than the blocks themselves. I had this book named the great pyramid decoded which explained that there were blocks held together with sheets of mortar that were in some places as thin as a sheet of aluminum foil. I have read elsewhere on the web that the chemical composition of the mortar is known but that it can't be reproduced today. I may be easily fascinated by this stuff, and there may be an better mortar now, but I just think that is really cool.

Meanwhile, a retired carpenter..

[Bob Cat - NYMPHS]

is building his own Stonehege - BY HAND, ALONE.

http://www.theforgottentechnology.com/

Re:Casting Vs Forming

[jafac]

Interesting line of thought -

One of the main binding factors of ancient Egyptian civilization was the common religion. And an interesting point about the religion, is that they (the priesthood) exercised very strict controls on everything related to the religion, including artistic style (and techniques), monumental architecture, funerary rituals and rites, language, etc. It was this cultural inertia that bound the Egyptian civilization together across thousands of years, dozens of dynasties, even through foreign invasions and occupations.

The very fabric of the civilization was guided by the notion that CHANGE IS BAD. Pharoh is God. As long as we follow our religion and keep God happy, and make sure God's remains are preserved FOREVER, then Egypt will continue forever.

By that notion alone, it seems unlikely that there was a vibrant experimentation going on.

From the art historian perspective, you can compare the stylistic qualities of sculpture over thousands of years, and the features remain virtually unchanged (except for the Armana period, which really only lasted a couple of decades). During Akhenaten's reign, this changed, because he ousted the priesthood, and introduced his own religion - and during this brief period, the art style changed dramatically. Then the priesthood regained control, and used his son, Tutenkamen, as a puppet, to restore the previous order, and the old art style returned, though it was never again as static - and began taking influence from other medeterranean cultures with which the Egyptians traded (ie. Greek, Persian, etc.)

I'm not saying that they did not discover the perfect concrete formula through experimentation (and it's pretty clear that there WAS a process of improvement in their embalming process over the centuries)- but what I'm saying is that taking 500 years of Roman history, and mapping that over to 7000 years of Egyptian history is like comparing apples to oranges. Egyptian progress most likely moved VERY slowly, in comparison. But they did have a lot of time to work at it.

Re:so why then use blocks ?

[LurkerXXX]

Ding, Ding, Ding. Give that man a cigar.

You can't just pour something the size of the pyramids and expect to have it set in any reasonable time frame.

Ever see movies of the building of the Hoover dam? It was done in a lot of small blocks, and for a very good reason:

"The Bureau of Reclamation engineers calculated that if the dam were built in a single continuous pour, the concrete would have gotten so hot that it would have taken 125 years for the concrete to cool to ambient temperatures. The resulting stresses would have caused the dam to crack and crumble"

Re:It has to be said

[sofar]

"I'd suspect that maybe the stones at the base might have needed to be stronger than the ones near the top."

No.

The compressional forces that concrete or any mineral type of rock can endure are almost endless. man-made concrete is just as strong as some of the toughest rocks in nature.

You don't see the grand canyon walls (larger and steeper than any pyramid) collapse? Those are (top 100's of feet) made out of sandstone, which is probably not even as strong as concrete or limestone.

Re:Casting Vs Forming

[Vreejack]

It has been long known that the internal and external blocks of the pyramids were different. It seems that an internal scaffolding of blocks was lain, on which a long pole with a target at the end could be mounted so that the edges could be kept straight and aligned as the external blocks were added. The outer blocks were long thought to be a more attractive grade of limestone, highly polished. They were also highly desirable for building materials and were often stolen by later Egyptians. Since they were more easily stolen from the bottom we have a possible explanation for why the blocks on top seem to be different from the blocks on the bottom, that being that the top blocks are simply exterior blocks which were too difficult to steal.

The brief article seems to imply that the authors of the study could not be certain of the top/bottom relationship because of their lack of material for study. This is unfortunate as I suspect with more material this hypothesis of their might be completely demolished. I have two major problems with it. First, they are materials scientists, not geologists, so they have no acknowledged expertise in the art of geology. Second, even if they were geologists, they are still arguing from ignorance, claiming that nature could not be responsible for the form of these limestone blocks. Well, nature is often a mystery to those who have not bothered looking at it, and it is easy to claim that something could not happen in nature if you are unfamiliar with it. Just ask the anti-Darwinists.