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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.'"

35 of 445 comments (clear)

  1. It has to be said by lecithin · · Score: 5, Funny

    "They found traces of a rapid chemical reaction which did not allow natural crystallization. "

    That is what I call concrete evidence!

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    1. Re:It has to be said by EvanED · · Score: 5, Insightful

      Nothing new, other than maybe they are saying we can now confirm it was concrete with modern analysis techniques.

      Which is PLENTY of reason for news, even if the theory was widely believed.

      I mean, there's a theory that the Sphinx was built about 10,000 years earlier than was previously thought, by an entirely different civilization. It's not widely believed, but the guy does have some evidence.

      As for the current theory, I doubt *IT* was widely believed either. I've watched a few shows on Egypt, and never heard of it before now.

    2. Re:It has to be said by jimstapleton · · Score: 5, Informative

      because in science, a hypothesis is interesting, but prooving a hypothesis is important. What you heard was the hypothesis. This right now is the information that major strides have been made towards actually prooving it.

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    3. Re:It has to be said by dr_dank · · Score: 5, Funny

      That is what I call concrete evidence!

      It would have been conclusively proven years ago, but the investigation was stonewalled.

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    4. Re:It has to be said by Kraeloc · · Score: 5, Insightful

      We never prove a hypothesis, we just find supporting evidence.

    5. Re:It has to be said by DilbertLand · · Score: 5, Insightful

      The difference is about the same as someone asking you to move 2000lbs of sand from your driveway to your roof using a ladder and someone asking you to lug a single 2000lb solid rock to the top of your roof. There's a big difference in logistics.

    6. Re:It has to be said by TofuDog · · Score: 4, Insightful

      Umm, no. We accept a hypothesis after rejecting alternative hypotheses. Strictly speaking, science never proves anything. This concept is at the core of the scientific method.

    7. Re:It has to be said by sofar · · Score: 4, Interesting

      "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.

    8. Re:It has to be said by big+tex · · Score: 4, Informative

      First off, your use of the work mould means you are either British or know nothing about concrete. The walls used to hold the uncured concrete are called forms.

      Making adjacent blocks with tight cracks is blindingly easy.
      First, pour one block. Start with a corner one. This takes (4) side forms.
      Second, strip the forms. Clean them.
      Third, set three forms, using the hardened block as the 4th wall. Pour this one.

      Repeat steps 2 and 3 ad nauseam.

      You could pour every other block, and come back and pour the ones in between.
      They even had the technology to make all of the blocks line up straight - string. We use the same technology today.

      Besides, making a sort of concrete from powdered stone and lime just to pour it at the bottom seems like a real bad idea - why not just carry the mud and forms to the top and save the effort of moving and aligning the final bricks?

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    9. Re:It has to be said by johansalk · · Score: 4, Insightful

      Actually, that's not the main difference that's noted in this discovery. After all, the pyramids builders did achieve mind boggling feats of logistics anyhow. The main difference is that it was thought that concrete had not been invented until the Romans. That's a 2500 years difference in dating an invention that's so critical to civilisation.

  2. Oh come on! by necro81 · · Score: 5, Funny

    How are we supposed to believe that an advanced alien race would still be using something so mundane as concrete?

    1. Re:Oh come on! by nullCRC · · Score: 5, Funny

      Maybe they were illegal aliens and lacked the funds...

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    2. Re:Oh come on! by dr_dank · · Score: 4, Funny

      It proves once and for all that the Egyptians were visited by Teamsters.

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  3. Casting Vs Forming by eldavojohn · · Score: 5, Informative
    I've poured a lot of concrete with my dad over the years. So I will share with you some of the useless knowledge I acquired before college. He has only a high school degree so it's not like he was a scholar on this material.

    My dad always used to tell me that when Alexandria was burned, all the publications holding the Roman recipe for concrete went with it. That, he claimed, was why all concrete poured was inferior to the Roman Aqueducts. And why it wasn't until 1948 that the right combination of limestone & other minerals was discovered to be able to resist water and hold that high a level of precision. Cement/concrete are by nature porous surfaces and so often sap water which causes structural problems. The fact that the some of the aqueducts still hold their accuracy within inches of their architectural specifications after 2000 years is nothing to overlook.

    If Egyptians (for thousands of years prior to the Romans) had experimented with or refined this process and if an Aristotelean (such as Demetrius of Phaleron) had moved this information to Alexandria, that would explain how the structures like the aqueducts were constructed with such high quality mixtures.

    I have one tiny problem with the summary as the article states:
    The Ancient Egyptians built their great Pyramids by pouring concrete into blocks high on the site rather than hauling up giant stones, according to a new Franco-American study.
    While summary uses the word cast:
    The reaction would be inexplicable if the stones were quarried, but perfectly comprehensible if one accepts that they were cast like concrete.
    I would like to point out that this is known as forming concrete and not casting concrete. The difference is like the difference between pouring concrete for a foundation of a house and laying brick. Laying brick is casting while pouring concrete (like the article alludes to) is called 'forming.'

    This might sound like a small matter but laying brick & forming concrete walls are two entirely different professions.

    In all honesty, if you were to ask me to construct a pyramid today--knowing what I know, I would build the core of the pyramid out of laid brick. And then I would, starting from the bottom, form up the angled sides and fill in those areas. If you're wondering why I would take this route, try it with paper. Cut out blocks of paper from a notebook without making marks and try to make a perfect angled edge between them. Pretty difficult. Now try it in three dimensions with 2000 year old tools.

    It makes sense that they would have both technologies (like the article states), one quarried for huge bricks and the other formed up ash, salt & lime. It would also explain a lot of technologies the Romans had.
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    1. Re:Casting Vs Forming by eldavojohn · · Score: 5, Interesting
      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.
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    2. Re:Casting Vs Forming by mrchaotica · · Score: 4, Informative
      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.

      To be fair, you should probably measure the duration of the civilization, not just the time when it was called an "empire." In that case, the Roman civilization (monarchy, republic, and empire) lasted from 753 BC to AD 476.

      Also, the Wikipedia article on Ancient Egypt says that your 7,000 year figure is high by a factor of 2:

      Ancient Egypt developed over at least three and a half millennia. It began with the incipient unification of Nile Valley polities around 3150 BC and is conventionally thought to have ended in 31 BC when the early Roman Empire conquered and absorbed Ptolemaic Egypt as a state.

      So the Egyptions lasted longer than the Romans, but not by nearly as wide a margin as you stated.

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  4. (obligatory grains of salt) by mmell · · Score: 5, Interesting
    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.

  5. Doesn't make sense by Waffle+Iron · · Score: 5, Funny

    In an era before the invention of the wheel, it wouldn't have been any easier to drag a 20-ton concrete mixer truck chassis up the pyramid than to just drag up a 20-ton block of stone.

  6. 2nd time I've heard this by jbeaupre · · Score: 4, Interesting

    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.

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  7. Re:so why then use blocks ? by imsabbel · · Score: 4, Insightful

    Because blocks are the most practical solution?

    It isnt really viable with bronze age technology to do large scale in-place casting.

    So with blocks, they could be prepared nearby, and when cured be put in place.

    The big advantage is not that they dont have to be lifted up, but that they dont have to be fetched from distant quarries.

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  8. That's cement, not concrete by Beryllium+Sphere(tm) · · Score: 4, Interesting

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

  9. 4000 AD by bronzey214 · · Score: 5, Funny

    I can only imagine archeologist's reactions when our society is kaput.

    "The Americans had slaves that carried concrete slabs to form long unending structures. We also have evidence that these were called "free-ways". We think these "free-ways" were in worship to some sort of God and the metal heaps on these "free-ways" offerings for this God."

  10. Re:Yeah, but... by outsider007 · · Score: 5, Funny

    No intelligent person believes that the pyramids were built by aliens.
    We know for a fact that they were built by humans.
    Aliens just supplied the anti-gravity beams.

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  11. Thermal stress by mrchaotica · · Score: 4, Informative

    Go look at a concrete highway sometime, and check whether the concrete is continuous (like asphalt*) or whether it has regular seams. There's a reason for the seams: namely, that concrete expands and contracts with temperature. If we poured roads as once continuous chunk they'd expand in the heat and buckle, or contract in the cold and crack. The seams are there to relieve the temperature-induced strain.

    Now, consider the fact that the Egyptions lived in the middle of the desert. One particular feature of such a climate is that there are wide extremes of temperature: it gets really hot during the day, and really cold at night. Once you realize that the Egyptions probably had prior experience with the materials before trying to build the biggest structure in the world out of them, you might expect that they'd realize the same thing current civil engineers do, and put in releases to prevent cracking. In 3D, this would mean pouring the concrete in blocks.

    (*note: asphalt can be laid in continuous strips because it's much less brittle than concrete, at least at normal service temperatures.)

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  12. Mortar by kaoshin · · Score: 4, Interesting

    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.

  13. Formula by Anonymous Coward · · Score: 5, Funny
    Is the activity of casting liquified lime depicted on any pictographs/heiroglyphics in Egypt?

    Yes. It goes like this:

    Bird's eye bird's eye, dancing guy, two chicks looking at each other, bird's eye, chicks again, that dog faced god looking to the heavens, some women throwing wheat into the air, guys picking ground, bird's eye, god of something, mound of cement.

    There you go!

    1. Re:Formula by feepness · · Score: 4, Funny

      Bird's eye bird's eye, dancing guy, two chicks looking at each other, bird's eye, chicks again, that dog faced god looking to the heavens, some women throwing wheat into the air, guys picking ground, bird's eye, god of something, mound of cement.

      First off your knowledge of ancient egyption is obviously flawed. Secondly... language! There could be children reading this.

    2. Re:Formula by TrevorB · · Score: 5, Funny

      First off your knowledge of ancient egyption is obviously flawed.

      Quit being a Grammar Centurion.

  14. A little insight by Anonymous Coward · · Score: 5, Informative

    As a student at Drexel, I have had the privilege of hearing about this research firsthand - it is more than convincing. There is no doubt in my mind that he is 100% correct. For those of you in doubt - he is not claiming that all stones were "cast" or "molded" into places. Only the ones at the top and on the outside of most of the "newer" pyramids. The older pyramids do not use this technology. It is believed the egyptians discovered this technology as they were building and their pyramids became more sofisticated as a result. You can just look at the pictures:

    The Bent Pyramid (an older pyramid), its obvious blocks put into place from a quarry up until where it bends.
    http://www.richard-seaman.com/Travel/Egypt/Dahshur /BentPyramid/EgyptianPoliceman.jpg

    Now, look inside the Red Pyramid (a newer pyramid), tell me they carved 26 million bricks with such perfect precision. They carved Limestone, using copper tools (ahem, softer than limestone), so perfectly together that you can't even fit a playing card between them? I don't think so.
    http://www.richard-seaman.com/Travel/Egypt/Dahshur /AllPyramids/StaircaseInsideRedPyramid.jpg

    This article can also be found on the New York Times http://www.nytimes.com/2006/12/01/science/01pyrami d.html?ref=science

  15. Well... by jd · · Score: 5, Funny

    ...the archaeologists were trying to cement their relationship with the aliens, who were stealing all the limelight.

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  16. Meanwhile, a retired carpenter.. by Bob+Cat+-+NYMPHS · · Score: 5, Interesting

    is building his own Stonehege - BY HAND, ALONE.

    http://www.theforgottentechnology.com/

  17. I seriously doubt it... SERIOUSLY by Micklewhite · · Score: 5, Funny

    I have a lot of trouble believing these findings. It's well known that the ancient Egyptians were a very 'slow on the uptake' sort of people. This is reasonably apparent with their crazy style of writing. The Egyptians had some notion that rhyming appeased the gods or something to that effect. So naturally all their writings rhymed. Take this classic example: 'Man with a snake, boat on a lake. Bird in the sky, weird curly eye'. If you could say the Egyptians contributed ANYTHING to modern society that would have to be rhyming. Before the Egyptians came along no society had developed an actual working rhyming system. The ancient Greeks came closest. Homer's Odyssey was the closest the Greeks ever came to an actual rhyming system, though, in its native Latin the Odyssey will cause a sane man to go mad.

    One might wonder what this has to do with the ancient Egyptians capacity to mix concrete. Well it has a LOT to do with it. You have to remember the ancient Egyptians were very keen on rhyming. The entire mummification process rhymed, as well as all the names of all the pharaohs. So it's only logical that all their building materials should rhyme as well. Concrete doesn't rhyme with anything. Therefore the ancient Egyptians didn't use it.

    This if you will, is the cornerstone of Egyptology.

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  18. Just FYI... by PhineusJWhoopee · · Score: 5, Informative
    Just FYI, the limestone blocks in question are *not* the stones you see at the base of the pyramids (for example, all the stones in this photo). These are made of granite.

    The limestones they are talking about used to cover the pyramid to give it flat sides, and the only remains left at Giza can be seen at the very top of the middle pyramid in this photo. (FWIW, this is the pyramid of Khafre (Chepren) - next the the Great Pyramid of Khufu (Cheops), which has had all of its limestone block cladding removed.)

    The third large pyramid at Giza (Menkare/Mycerinus, foreground in the group photo) was intended to be covered in granite cladding. ed

  19. Re:so why then use blocks ? by LurkerXXX · · Score: 4, Interesting

    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"

  20. Bronze, not copper. by Medievalist · · Score: 4, Informative
    They carved Limestone, using copper tools (ahem, softer than limestone), so perfectly together that you can't even fit a playing card between them? I don't think so.
    Bronze, not copper. HUGE difference.

    Also, the bronze technology of the time was more advanced than anything known to Victorian civilization - Burton writes about the bronze chisel (found inside a pyramid or temple, I forget) that was harder than wrought iron when he's discussing the switch from bronze weapons to iron weapons in The Book of the Sword.

    We know that the ancient Egyptians had bronze tools hard enough to work limestone. We have at least one example.