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

Casting Vs Forming

[eldavojohn]

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.

Re:Casting Vs Forming

[kfg]

He has only a high school degree so it's not like he was a scholar on this material.

Bucky Fuller only had a high school degree, so it's not like he was a scholar on building geodesic domes.

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.

Euclid: circa 365-275 BC. I might also note that the ancient Egyptians were so adept at making marks directly on stone that some of those marks still survive and that they invented the surveyor's wheel. They weren't cave men (now, don't get up on the wrong side of the rock. I didn't mean anything by it).

KFG

Re:Casting Vs Forming

[notthe9]

Forming, rather than casting? In my experience with structural concrete (which is not all that much: I am an undergraduate structural engineerning student) I have encountered the term cast used with concrete. I have heard "cast-in-place" contrasted with precast concrete.

The ACI Committee 318 Building Code defines "Precast concrete" as "Structural concrete element cast elsewhere than its final position in the structure," which would suggest to me that structural concrete members that are not precast are indeed cast in their final positions.

Re:Casting Vs Forming

[mrchaotica]

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.

Re:It has to be said

[DragonFodder]

Why is this even news? I recall reading about this theory back in the late 80's. Nothing new, other than maybe they are saying we can now confirm it was concrete with modern analysis techniques.

Re:It has to be said

[jimstapleton]

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.

Re:I can hear the Egyptologists now...

[starwed]

They're just saying some>/i> of the stones were made this way. Not all of them.

Thermal stress

[mrchaotica]

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.)

Re:so why then use blocks ?

[nine-times]

Have you ever noticed that sidewalks are divided into little squares? I'm no expert, so there may be lots of reasons for it I haven't thought of, and it may not be the same thing at all. However, it seems to me it might be easier to get concrete to dry in little blocks than in one huge pyramid a hundred feet tall. Also, with heat/moisture, these things swell and shrink, and it's good to have a division so they won't crack and fall apart.

A little insight

[Anonymous Coward]

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

Re:A little insight

[smellsofbikes]

Note that Navajo and Zuni (and many, many other prehistoric civilizations) drilled holes in stones using pieces of straw. Which are, y'know, six orders of magnitude softer than stone. They did it using abrasives. (sand and spit, as it happens.) There's no rule that the Egyptians couldn't do the same thing. It's quite possible to dry-fit stone, using nothing but other stones, to the point you can't fit paper between two of them: you hit the high points, rub the stones together, see where they rubbed, repeat until you're at the limit of resolution, which is determined by the surface marking compound. In their case they probably used the dust from the hammering. It takes a long, long, long time but it's very effective at making astoundingly tight walls. Now, it's a *lot* trickier to rub 2000 ton stones together. However, it's possible to make plates that are nearly perfectly flat, again limited by your surface marking compound, by the three-plate method. You rub plate A and B together until they look pretty flat, then plate B and plate C, then plate C and plate A. If you do that for long enough, all three will be true flat. (There is a possible exception to this, that a mathematician found, where you'll form weird saddle-shaped structures, but it doesn't occur if you randomly rotate the plates between matches.) Anyway, then you can use the plate as your indicator and build all your stone surfaces to be, well, arbitrarily flat.

Brick Pyramids

[spike2131]

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.

A lot of the later pyramids actually were built with a core of laid brick, and cased in stone. These didn't hold up as well as the older, all stone pyramids, like the Great Pyramid, because the bricks were made out of mud and eventually turned to dust. Today, a lot of the brick pyramids basically resemble mounds of dirt and rock, with the original pyramid shape just barely distinguishable.

This Isn't Exactly New

[RetiefUnwound]

A book I have - published back in 1988 proposed the same idea. It's a good read. Here's the Amazon link if anyone wants to try and pick up a copy:

The Pryamids

Re:Why quarry granite then

[Panaflex]

It's called "Scope creep." Wonder who was the project manager on that one?

Just FYI...

[PhineusJWhoopee]

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

Re:4000 AD

[Khomar]

That reminds me of a great children's book I ran across a few years ago called Motel of the Mysteries. It was a comical take on what archaeologists might think of our culture as they unearth a 20th century motel. It really makes you wonder how utterly wrong our understanding of history may be. The one thing I remember best from the history of ancient Greece is that all of our knowledge of that culture is based on a single book and a few fragments.

Bronze, not copper.

[Medievalist]

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.

Re:It has to be said

[cuantar]

Newton's laws of motion are still called 'laws' even though we've known for the better part of a century now that they're wrong. In modern science, that distinction between 'law' and 'theory' really doesn't exist, as any good scientist will take everything that has been 'proved' with a grain of salt.

Re:Mortar

[smellsofbikes]

I don't know that this answers your question, but people spent millenia dry-fitting stones by hammering down the high points (with other stones) and then rubbing the stones together. (People still make precision flat metal this way for machine tools. It's called way-scraping. Sorry I can't find a better link.) The point being, when they got done you had two rocks that were sufficiently flat that when put together they were within a dozen thousandths of an inch of each other -- you couldn't fit a credit card between them, and sometimes not even a piece of paper. (Common paper is pretty close to 0.002"/0.05mm thick.) So if you do *that*, then put a smidge of mortar in there and put the 2000 ton block down on top of the mortar, that might be responsible for it being only the thickness of aluminum foil. Which is a good thing: the thinner the adhesive, the better the bond, generally speaking.

Joseph Davidovits

[danelav]

To give credit, the name I believe to be first associated with this theory is Joseph Davidovits. He's been claiming poured ("geopolymerized") pyramids for a long time.

Re:It has to be said

[Anonymous Coward]

[Theory that the Sphinx was built 10,000 years ago]

It's actually very compelling evidence - essentially lots of evidence of water erosion in the enclosure,

Sorry to rain on your parade (Oh man, I'm evil today.) but that "evidence" is complete bunkum. Actual geologists do not accept the claim that weather patterns are distinguished by the substance that caused the erosion -- in fact, it's a quack creation science idea. The difference in erosion patterns here in the real world is caused by the type of rock, not the medium of erosion. Horizontal bars of erosion are NOT caused by wind, but by the fact that various types of sedimentary rock are formed from alternating hard and soft layers. Likewise, crumbling patterns are not caused by water, but are due to softer rock (such as limestone) that just collapses as it erodes.
  This theory is not a work of a lone genius who's being sneered at by the pompous scientific community because his ideas are too new -- he's a loon, and the ideas from which he built his theory had already been thoroughly discredited before he even began, forcing him to appeal instead to the "C- in science" public via a TV special years ago.
  - mantar

Re:It has to be said

[causality]

That's about as plausible as any more serious explanation I have ever heard.

The problem with explaining say, the Great Pyramid at Giza, is that given near-infinite wealth and all available modern technology, we either could not build it today or it would be extremely difficult.

From http://en.wikipedia.org/wiki/Great_Pyramid_of_Giza :

... The casing stones of the Great Pyramid and Khafre's Pyramid (constructed directly beside it) were cut to such optical precision as to be off true plane over their entire surface area by only 1/50th of an inch. They were fitted together so perfectly that the tip of a knife cannot be inserted between the joints even to this day.

The passages inside the pyramid are all extremely straight and precise, such that the longest of them, referred to as the descending passage, which is 350' 0.25" long deviates from being truly straight by less then 0.25 inches, while one of the shorter passages with a length of just over 150 feet deviates from being truly straight by a mere 0.020 inches. These and the above statistics prove the pyramid to be literally the most accurately constructed building on the face of the earth despite having been created several millennia ago. All theories which sufficiently allow for this level of accuracy assume a level of technology approximately equal to or exceeding current technology, at least in the area of tool making and construction.

Whether they can cast concrete or not, the idea that a civilization which did not even have the wheel could build a structure that was visually indistinguishable from the Great Pyramid, if they were willing to work hard enough to do it, could maybe be plausible. But the idea that they could have built such a structure, to those tolerances and with that degree of precision is laughable at best. The diamond-tipped blades typically used to cut large blocks of stone wear and warp (both due to mechanical stress and due to heat) during use sufficiently that they could not cut stone with that kind of precision -- to the casual observer the cut would look quite straight, but detailed measurements would not show the kind of tolerances found in the Great Pyramid.

Additionally, the Great Pyramid is currently aligned with true (not magnetic) North with only 3/60th of one degree of error; bear in mind the true North shifts position over time, therefore in the past it was aligned exactly. The king's coffer in the Grand Chamber is made of one solid piece of granite; microscopic analysis of the holes drilled into it indicate that it had to have been done with a fixed-point drill, using hard jewel bits and a drilling force of two tons. The measurements of the pyramid's features "coincidentally" yields, to a high precision, numbers such as the number of days in a year, the earth's distance to the sun, the earth's mass, the speed of light, the sun's radius, etc. See this link.

The Pyramid is far more mysterious than most people would have you believe. My personal theory is that civilization is cyclical just as every other aspect of nature, that is, that eons ago there were civilizations that existed and had high technology, probably superior to ours, which either eventually destroy themselves (and civilization) or are destroyed by polar reversals, asteroid impacts, or other such cataclysms. The idea that we are the very first people who have ever had computing power or nanotechnology is at best an unfounded assumption.

While theories etc. are fun, I honestly have to say that I have no idea how that pyramid got there. And from what I can tell, neither does anyone else.

Re:It has to be said

[big tex]

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?

Re:It has to be said

[big tex]

Actually, straight lines are relatively easy.

There's this great technology called string. Pull it tight, and you can determine without much effort where to chip as to have a straight wall.

video

[gerbouille]

OK, I give up my moderation rights to share with you a 2002 video (in French) about an experiment on the "egyptian" concrete casting.
Enjoy.

Re:It has to be said

[DrexelPyramid1]

Hi - I'm Alex Moseson, one of the researchers at Drexel University on this project. Many of your observations are great! I HIGHLY recommend the following two links:

1. Joseph Davidovits (who first proposed it decades ago) actually making the pyramid blocks by pouring them! http://www.youtube.com/watch?v=znQk_yBHre4
2. Official presentation from Dr. Michel Barsoum's group at Drexel University: http://www.mse.drexel.edu/max/PyramidPresentation. htm. (Sorry it's HUGE right now, we'll be compressing it soon.)

I agree, you wouldn't expect limestone to dissolve in water, and you do describe the general process for Portland Cement. "Geopolymers" however, work on an entirely different chemical reaction. You're also right about this being further work on Davidovits' original theory. Some more food for thought now. Here are some difficulties with the "carve and hoist" theory:

• Multi-ton blocks, up to 60 tons each and an average of about 2.5 tons, fit together so precisely that a playing card can't be wedged between them.
• The Great Pyramid is the largest of all the pyramids. To fit into the accepted timeline for its construction, one block, weighing on average more than two tons, would have to be placed every six minutes. The number of men working in the quarries to harvest the blocks, to transport them across the desert, and to drop them into place at the site is estimated to be substantially larger than the population of the nearby city at Giza.
• Their copper tools would have blunted almost immediately when carving solid limestone.
• Many of the outer pyramid blocks obviously and curiously take the non-uniform shape of surrounding blocks.

All that being said, there are also some difficulties with the "poured" theory:

• There are obvious natural grains in granite pyramid blocks. This means they're almost certainly natural.
• Observation has shown that the lower 2/3 of the pyramid seem to be filled with rubble! (rocks which seem to have been cut and "tossed" in.
• Archeologists have discovered a quarry which shows evidence of carved blocks.

So, we propose a hybrid theory. Portions of the pyramid were cast, while others were poured. This is work involving PhDs from around the world, electron microscopes, and a couple of grad students (like myself) that make this stuff daily! Our work shows that the outer and inner casing blocks (the outermost part, and the inside hallway lining) are not natural limestone. They are however, consistent with casting! Take the test in the presentation! You'll be able to see with your own eyes which blocks are cast, and which are poured. Check out the links above for more information! We don't pretend to know it all. More research is needed. Whatever it has to do with the pyramids though, we're sure this geopolymer stuff will be useful as a sustainable, environmentally friendly building material. Think developing communities upgrading from grass huts and mud brick to roads and "geopolymer concrete" houses. For next to free. More details to come :)