Concrete in Egyptian Pyramids

I saw this in the new today. Had never heard this reseach angle before.

Limestone based concrete.

A researcher believes some of the stones may have been cast. If so, the builders
show even more technology. Were the Egyptians believed to have know of concrete
and to have used it in other projects?

Houston Cronicle Story

I personally had heard this claim in the early 1990's, but it was "debunked" back then.

If this is true, then one thing that will need to be explained is why so much of the pyramids structure IS made of laboriously cut stones, and not concrete. The same with home construction, etc.

Perhaps the pyramids had a ceremonial symbolism that required cut stones. If so, then why is there ANY concrete present?

Also, if they knew the tech for concrete, why didn't they use it where it wouldn't have had any ritual significance? They did a lot of flood control and irrigation---which is precisely HOW the Romans refined their own concrete abilities. And yet, they didn't use it for irrigation troughs of dams or breakwaters . . . in the land where erosion control was born . . .

Not that these considerations make it impossible for them to have understood how to make concrete. But, if it proves true, the reasons why they only used it for ceremonial constructions (pyramids) should prove fascinating.

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The first thing that popped into my mind was recollection of something I read several years ago about how concrete was used for spot repairs and could the researcher from Drexel University have tested these samples?

When I read the article, my suspicion was validated. However, I also think that it would not be impossible for Egyptians to have used concrete. Put simply, it's a mix of several ingredients that hardens to an almost rock like material. I would think that it would be conceivable that such a mixture could have be 'accidentally' discovered.

I would also be curious if rocks from the quarries have been tested. I'm not a mineralologist, but there are several places on earth with unique characteristics. Could the lime stone (concrete) blocks have been cut from such a location?

Never-the-less, very interesting!

Originally posted by DCFusionWhen I read the article, my suspicion was validated. However, I also think that it would not be impossible for Egyptians to have used concrete.

The curing time for a huge 2 ton block of concrete would have been ridiculously long. It took 2 days for a sidewalk out in front of my house to cure, and that's only 2 inches thick and only 2 feet by 3 feet.

This PDF mentions curing times of 7 days or more for a slab (house, I believe.)
www.nrmca.org...

I would also be curious if rocks from the quarries have been tested. I'm not a mineralologist, but there are several places on earth with unique characteristics. Could the lime stone (concrete) blocks have been cut from such a location?

Yes, they know which quarries they come from. There's also notes (ostrika) mentioning deliveries of stone from those quarries.

Originally posted by DCFusion
...However, I also think that it would not be impossible for Egyptians to have used concrete. Put simply, it's a mix of several ingredients that hardens to an almost rock like material. I would think that it would be conceivable that such a mixture could have be 'accidentally' discovered. ...

Ermmm... Concrete was around in already in Roman times:

archserve.id.ucsb.edu...

However to built the entire pyramid in concrete , you would require reinforced concrete, these days it's reinforced with steel bars:

en.wikipedia.org...

And that, was not available to egyptians.

The type of concrete the experts are talking about it's not the commun type we use this days!, it looks that this egiptian kind of concrete cristalizes after some time in something very hard and strong, gaining almoust rock caracteristics.

Originally posted by Umbra Sideralis
... after some time in something very hard and strong, gaining almoust rock caracteristics.

ermmm, that's concrete. Whatever time it is from, even the Roman concrete was like that, that's why you use conrete in the first place.

Originally posted by Byrd


This PDF mentions curing times of 7 days or more for a slab (house, I believe.)
www.nrmca.org...

Just want to insert some technical stuff to consider. Don't confuse "cure time" with "set time". When you read that your slab for your house needs at least 7 days cure time that means it needs to set to a point that allows it to gain sufficient compressive strength - a strength mandated by building codes. But it's "set" (i.e. solid with some measurable compressive strength) long before that. Now with the amount of time that would be required to form, pour and un-form a course of stones around one level of the pyramid, there would be more than sufficient time for a given stone to set and even cure to sufficient compressive strength to go on to forming the next course above it. In fact, it's a lot more believable that the pyramids could get completed within a lifetime in this manner than it is that 2 ton blocks were hand-quarried and then rolled on logs for hundreds of miles.

For instance, the Hoover dam is still "curing", but it set to sufficient strength to continue construction not long after a given section was poured.

I'm not saying I buy that the stones were cast - I'm just saying it is an EXTREMELY plausible explanation of construction technique. In fact, it's the most plausible one to date. Let's face it, a limestone based slurry is an easy thing to achieve, and work with.

[edit on 12-2-2006 by Valhall]

[edit on 12-2-2006 by Valhall]

Originally posted by jmlima

Originally posted by Umbra Sideralis
... after some time in something very hard and strong, gaining almoust rock caracteristics.

ermmm, that's concrete. Whatever time it is from, even the Roman concrete was like that, that's why you use conrete in the first place.

interesting how you cut from my quote what makes all the diference...Cristalization!

modern concrete do not get it's hardness from cristalization.

I must assume my error, the cement react with water making a fiber cristallization process, so i was wrong. sorry for that mate

The Poured Limestone Slurry idea is backed up by the fact that you always see scientist's trying to wedge a peice of paper in between the joints and cant.

It would be more reasonable to expect a concrete type pour with formwork to get these joints so precise than it would be to expect precision cutting by chipping with a hammer and chisel - pure and simple.

A geologist I know posted this on Usenet

All I have seen of this so far is a 57 mb 36 page PDF slide show by
one of the authors of ths new paper.... it resorts to the "copper
chisels, the only tool the AE ever had" strawman at various places. A
ridiculously common fringe archeology ploy that I have seen so many
others use in the past. Not a very good sign at all. It also seems to
suggest that clearly weathered limestone masonry is cast because it
looks different from the somewhat freshly exposed and less weathered
blocks nearby. I hope that their "strange" chemical analysis is not
based on detritus from salt weathered rock surfaces... I like the
section on the granite blocks as well... since they are natural rock
the AE clearly had the ability to move heavy weights to great heights
and carve hardrocks with the tools and technology attributed to them
during the OK. Invalidates all those "how would they/you carve this"?
proclamations on the previous slides with strange shaped limestone
blocks. Instead the slide show resorts to "true and incomprehensible
mystery" innuendo in an apparent attempt to sidstep that fact... why
because the ancient Egyptians only had "soft copper" to cave the
granite, etc. I always get a good laugh from these people.... never
ever fails It's good to know the poured-rock crowd has finally
started to realize that the granite in the GP cannot be claimed to be
synthetic without them looking like complete fools.

Quite remarkable just how susceptible the rocks of Member II are to
agglomeration in water considering the solution widened joints and
colour bands present in them (El Aref & Refai 1987, Gauri &
Bandyopadhyay 1999). I guess none of these people realize that during
the Pliocene the Mediterranean Sea transgressed into the Nile valley
causing the Giza Plateau to become a peninsula. There are 2 levels of
30 m high shoreline eroded cliffs on the north and west Mokattam
escarpments just a short distance (the closest a few hundred meters or
so) from the Pyramids (Aigner 1983). That is, most of these rocks
around the Sphinx were below sea level for a very long time during
this period. It's remarkable that that completely non-existent 12 foot
thick bed of "kaolin-rich" limestone that Morris (1994) asserts exists
in Member II didn't turn in to mud and squirt away under the weight of
the overlying rock.... truly remarkable!!! I don't know what's more
remarkable that lack of squirting agglomeration mud or that someone
would think that a piece of weathered detritus sitting on the surface
is a representative sample of in-situ unweathered rock on the Giza
Plateau.

Aigner, T. (1983) A Pliocene cliff-line around the Giza Pyramids
Plateau, Egypt. Palaeogeography, Palaeoclimatology, Palaeoecology, 42,
313-322.

El Aref, M. M., & Refai, E. (1987) Paleokarst processes in the Eocene
limestones of the Pyramids Plateau, Giza. Egypt. J. Afr. Earth Sci.,
6, 367-377.

Gauri, K.L. & Bandyopadhyay, J.K. (1999) Carbonate stone: chemical
behavior, durability, and conservation. Wiley, New York, 284 p.

Morris, M. (1994) Response (to Harrell in letters to the Editor).
Journal of Geological Education, 42, 198-203.

57 mb PDF file
www.drexel.edu...

Archae Solenhofen

Im just going to update this thread with an article from May 2007. I found this from another thread on ATS today and was amazed! I am prepared to be doubly amazed if we can actually learn how to make concrete in a more environmentally friendly fashion from ancient construction technology!

Full Article

A year and a half later, after extensive scanning electron microscope (SEM) observations and other testing, Barsoum and his research group finally began to draw some conclusions about the pyramids. They found that the tiniest structures within the inner and outer casing stones were indeed consistent with a reconstituted limestone. The cement binding the limestone aggregate was either silicon dioxide (the building block of quartz) or a calcium and magnesium-rich silicate mineral.

The stones also had a high water content—unusual for the normally dry, natural limestone found on the Giza plateau—and the cementing phases, in both the inner and outer casing stones, were amorphous, in other words, their atoms were not arranged in a regular and periodic array. Sedimentary rocks such as limestone are seldom, if ever, amorphous.

The sample chemistries the researchers found do not exist anywhere in nature. “Therefore,” says Barsoum, “it’s very improbable that the outer and inner casing stones that we examined were chiseled from a natural limestone block.”

More startlingly, Barsoum and another of his graduate students, Aaron Sakulich, recently discovered the presence of silicon dioxide nanoscale spheres (with diameters only billionths of a meter across) in one of the samples. This discovery further confirms that these blocks are not natural limestone.

Originally posted by Byrd
Yes, they know which quarries they come from. There's also notes (ostrika) mentioning deliveries of stone from those quarries.

You would still need to quarry limestone and transport it for making the concrete, but now its actually a feasible feat - transporting stones as opposed to 2 tonne rocks.

The problem is the limestone used in making the pyramids is of a "fine" texture (with lots of fossil inclusions), this would require grinding up the limestone, separating out the fossils then re-adding them (versus the gravel/rubble filled concrete the Egyptians used as Saqara). Interestingly enough the Egyptians dumped hundreds of tons of limestone rubble near the pyramids- why didn't they use it to make concrete?

Interesting, is there a rash of interest in this theory ?

I posted a thread entitled MIT class explores controversial pyramid theory with scale model.

As you can see it did not appear to be of interest but I thought it was purely from the fact of MIT being involved.

Originally posted by Byrd

The curing time for a huge 2 ton block of concrete would have been ridiculously long. It took 2 days for a sidewalk out in front of my house to cure, and that's only 2 inches thick and only 2 feet by 3 feet.

This PDF mentions curing times of 7 days or more for a slab (house, I believe.)
www.nrmca.org...

Good point. Aren't there sections of the Boulder Dam that are still curing to this day? How long would it have taken for a structure the size of the pyramid to cure? Perhaps thats why so little was used?

reply to post by Dae


Thanks for the info update.

Isn't it believed that the outside was covered with another layer of material to yield a smooth surface. Could be that is part of it. I do believe that most of it was large blocks as history has speculated.

They were covered by tura limestone, a part of that covering still remains on one and there are bits and pieces at the base of all of them.

Originally posted by Shazam The Unbowed
Good point.

I actually thought the good point was Valhall saying the curing time is irrelevant and that it was the set time that was the important note - like it was said the Hoover Dam is still curing but manages to still be strong to hold back water, Giza is just standing there supporting itself.

Hanslune I dont see how your problem is a problem, compared to constructing the whole of the Giza pyramid out of 2 ton blocks and heaving them up the structure!

So we have the OP article, my article and Sherpa's MIT article all about real scientists looking into this with real scientific instruments - that and the plausibility of concrete versus 2 ton blocks - if I had to stick my flag of belief in one of these theories, Its going to have to be the concrete.

Article

An egg-shaped cavity marked by the arrow spans two massive blocks on the north side of Senefru's Bent Pyramid must have been formed when the blocks were cast around a small rock or debris that was present. Credit: Michel Barsoum, Drexel University