Students Testing Egyptian Pyramid "Concrete" Hypothesis

Students Testing Egyptian Pyramid "Concrete" Hypothesis

Thursday, April 17, 2008

Keywords: pyramids, limestone, concrete, geopolymer, petrography, quarrying
Perhaps you've heard of the unlikely hypothesis that blocks of the Egyptian pyramids aren't actually stone but a form of ancient concrete cast in situ. This unusual notion has been touted by French chemical engineer Joseph Davidovits, who studies, promotes, and sells geological-based polymers at his Geopolymer Institute -- you'll find details about his ideas below and at his website. Recently, Michel Barsoum, a materials-science professor, has been supporting Davidovits' hypothesis that the blocks were cast in place, not carved. An article (posted below) from Live Science discusses Barsoum's study. Petrographer Dipayan Jana, though, has shown that specimens from the Great Pyramid at Giza are mineralogically and microstructurally consistent with local limestone, and no signs of Davidovits' geopolymers were found in the pyramid specimens -- his research is much more convincing than anything from Davidovits or Barsoum, and I've included a link to Jana's paper below. Now, a course at MIT involves students constructing a model pyramid using concrete and geopolymers. Their instructor, Lin Hobbs, a professor of materials and nuclear engineering, hopes that the model will help settle the debate. Hobbs says he remains open-minded and, "My own take is, they probably did both--cut some and cast some." This story is first below. My take? I agree that the topic should be studied seriously, and I posted back in December that ancient Egyptian glassmaking techniques were more sophisticated than previously thought. But Davidovits's pet idea is unsupported by the petrographic and archaeological evidence, and it will likely remain that way. But this a good application of experimental archaeology and shows students how to test hypotheses.
Above: An Egyptian man stands on blocks of the Great Pyramid at Giza. Credit: Martin Gray/Magic Planet.
Excerpts from MIT News:
Gathering "Concrete" Evidence
By David Chandler
Even though they are among the best-known structures on Earth, the pyramids of Egypt may still hold surprises. This spring, an MIT class is testing a controversial theory that some of the giant blocks that make up the great pyramids of Giza may have been cast in place from concrete, rather than quarried and moved into position.
In order to help identify blocks that were cast rather than quarried, students in the class, "Materials in Human Experience" (class 3.094), are assembling a small pyramid using a combination of both kinds of material. They will then use techniques such as microscopic imagery and chemical analysis to look for signs that might provide ways of telling the difference on samples from the Great Pyramid itself. . .
In fact, the very idea has been so controversial that "you can't get research funding, and it's difficult to get a paper through peer review," says Linn Hobbs, professor of materials science and engineering and professor of nuclear science and engineering at MIT and coteacher of the pyramid-building class. . .
The materials and know-how needed to cast the pyramids' giant 2-1/2 ton blocks in place, rather than quarrying and moving blocks of solid limestone, was definitely available to the Egyptians, Hobbs explains. At least 90 percent of the material would have consisted of powdered limestone, and Egyptian limestone is especially fragile and can easily be reduced to finely divided sludge simply by soaking it in water. The rest--the binder or cement--could have been made from materials they were known to have had and used for other purposes.
The binder, known as a geopolymer, could have been made from lime, kaolinite (a kind of clay), a fine silica (such as diatomaceous earth) and natron (sodium carbonate). The same ingredients were used by the Egyptians to make self-glazing pottery ornaments, a material called Egyptian faience. . .
Hobbs is not pushing the cast-block theory, which was first advanced by French materials chemist Joseph Davidovits, who invented (or perhaps reinvented) the geopolymer formula. Hobbs calls himself an agnostic on the matter, but thinks that it is a theory that deserves serious study and investigation.
"My own take is, they probably did both--cut some and cast some," he says. . .

To read the rest of the article, visit the MIT website:
http://web.mit.edu/newsoffice/2008/pyramid-tt0402.html
* * *
Excerpts from the Boston Globe:
A New Angle on the Pyramids
By Colin Nickerson
It's a theory that gives indigestion to mainstream archeologists. Namely, that some of the immense blocks of Egypt's Great Pyramids might have been cast from synthetic material - the world's first concrete - not just carved whole from quarries and lugged into place by armies of toilers. . .
"It could be they used less sweat and more smarts," said Linn W. Hobbs, professor of materials science at Massachusetts Institute of Technology. "Maybe the ancient Egyptians didn't just leave us mysterious monuments and mummies. Maybe they invented concrete 2,000 years before the Romans. . ."
A handful of determined materials scientists are carrying out experiments with crushed limestone and natural binding chemicals - stuff that would have been readily available to ancient Egyptians - designed to show that blocks on the upper reaches of the pyramids may have been cast in place from a slurry poured into wooden molds.
These researchers at labs in Cambridge, Philadelphia, and St. Quentin, France, are trying to demonstrate that Egyptians of about 2,500 BC could have been the true inventors of the poured substance. . .
Now a scale-model pyramid is rising in Hobbs's sixth-floor lab, a construction made of quarried limestone as well as concrete-like blocks cast from crushed limestone sludge fortified with dollops of kaolinite clay, silica, and natural desert salts - called natron - like those used by ancient Egyptians to mummify corpses. . .
"The degree of hostility aimed at experimentation is disturbing," he said. "Too many big egos and too many published works may be riding on the idea that every pyramid block was carved, not cast."
Archeologists, however, say there is simply no evidence that the pyramids are built of anything other than huge limestone blocks. Any synthetic material showing up in tests - as it has occasionally, even in work not trying to prove a concrete connection - is probably just slop from "modern" repairs done over the centuries, they say.
"The blocks were quarried locally and dragged to the site on sleds," said Kathryn Bard, an Egyptologist at Boston University and author of a new book An Introduction to the Archaeology of Ancient Egypt. "There is just no evidence for making concrete, and there is no evidence that ancient Egyptians used the stuff," she said. . .

To read the rest of the article, visit the Boston Globe website:
http://www.boston.com/news/science/articles/2008/04/22/a_new_angle_on_pyramids/
* * *
Excerpts from Wikipedia:
Joseph Davidovits - Archaeological Theories
Davidovits was not convinced that the ancient Egyptians possessed the tools or technology to carve and haul the huge (2.5 to 15 ton) limestone blocks that made up the Great Pyramid. Davidovits suggested that the blocks were molded in place by using a form of limestone concrete. According to his theory, a soft limestone with a high kaolinite content was quarried in the wadi on the south of the Giza plateau. It was then dissolved in large, Nile-fed pools until it became a watery slurry. Lime (found in the ash of ancient cooking fires) and natron (also used by the Egyptians in mummification) was mixed in. The pools were then left to evaporate, leaving behind a moist, clay-like mixture. This wet "concrete" would be carried to the construction site where it would be packed into reusable wooden molds. In the next few days the mixture would undergo a chemical hydration reaction similar to the setting of cement.
Using Davidovits' theory, no large gangs would be needed to haul blocks and no huge and unwieldy ramps would be needed to transport the blocks up the side of the pyramid. No chiseling or carving with soft bronze tools would be required to dress their surfaces and new blocks could be cast in place, on top of and pressed against the old blocks. This would account for the unerring precision of the joints of the casing stones (the blocks of the core show tools marks and were cut with much lower tolerances). Proof-of-concept experiments using similar compounds were carried out at Davidovit's geopolymer institute. . . According to Davidovits the architects possessed at least two concrete formulas: one for the large structural blocks and another for the white casing stones. He argues earlier pyramids, brick structures, and stone vases were built using similar techniques.
Although his ideas are not accepted by mainstream Egyptologists, in December 2006, Michel Barsoum, Adrish Ganguly, and Gilles Hug published a peer-reviewed paper in the Journal of the American Ceramic Society stating that parts of the pyramid were cast with a type of limestone concrete.
Dipayan Jana, a petrographer, made a presentation to the ICMA (International Cement Microscopy Association) in 2007 and gave a paper in which he concludes "we are far from accepting even as a remote possibility of a 'manmade' origin of pyramid stones."

To read the rest of this entry, visit Wikipedia:
http://en.wikipedia.org/wiki/Joseph_Davidovits
* * *
Excerpts from Live Science:
The Surprising Truth Behind the Construction of the Great Pyramid
By Sheila Berninger and Dorilona Rose
18 May 2007
“This is not my day job.” So begins Michel Barsoum as he recounts his foray into the mysteries of the Great Pyramids of Egypt. As a well respected researcher in the field of ceramics, Barsoum never expected his career to take him down a path of history, archaeology, and “political” science, with materials research mixed in. . .
Then Barsoum received an unexpected phone call from Michael Carrell, a friend of a retired colleague of Barsoum, who called to chat with the Egyptian-born Barsoum about how much he knew of the mysteries surrounding the building of the Great Pyramids of Giza, the only remaining of the seven wonders of the ancient world. . .
According to the caller, the mysteries had actually been solved by Joseph Davidovits, Director of the Geopolymer Institute in St. Quentin, France, more than two decades ago. Davidovits claimed that the stones of the pyramids were actually made of a very early form of concrete created using a mixture of limestone, clay, lime, and water.   “It was at this point in the conversation that I burst out laughing,” says Barsoum. If the pyramids were indeed cast, he says, someone should have proven it beyond a doubt by now, in this day and age, with just a few hours of electron microscopy. . .  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 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”. . .

To read the rest of the article, visit the Live Science website:
http://www.livescience.com/history/070518_bts_barsoum_pyramids.html
* * *
Excerpts from Jana (2007):
Earthquake Evidence from Detailed Petrographic Examinations of Casing Stones from the Great Pyramid of Khufu, a Natural Limestone from Tura, and a Man-made (Geopolymeric) Limestone
Dipayan Jana
The present study, based on detailed textural, mineralogical, microstructural, and microchemical analyses of pyramid casing stones, a natural limestone from Tura, and a geopolymeric limestone from Davidovits conclusively justifies the following statements:
(1) . . . There is no textural or microstructural evidence of a “reconstituted” limestone in the examined pyramid casing stones. . . Both pyramid casing stones and the limestone from Tura show a normal, geologic particulate texture of variably porous to dense bioclastic microcrystalline limestone. . . Despite the reported broad visual and bulk chemical compositional similarities, duplicating the intricate textural and microstructural similarities of pyramid stones and natural limestone by a “reconstituted” limestone is a challenge that far from being fulfilled. . .
(2) . . . Perhaps the most important finding in this study is the lack of evidence of an alkali and/or aluminosilicate-based composition of the binder phase in the casing stone samples of the Khufu pyramid, which is the essence of the limenatron-clay-based recipe of the geopolymer hypothesis proposed by Davidovits. . .
(3) . . . Contrary to the previous reports on the presence of calcium phosphate and silicoaluminate phases in the casing stone sample from the Khufu pyramid, and, therefore, the notion of its synthetic origin, the present study determined a zone of contamination in the casing stone adjacent to the coating where the porous microstructure of the limestone was invaded by phosphates from the coating. . .
(4) . . . Geologically normal silica-rich microconstituents in the casing stones and the limestone from Tura. . .
Also yet to be demonstrated by the proponents of the “cast-in-place concrete” hypothesis is a synthetic geopolymeric limestone sample that is similar to the casing stone not only in visual appearance and bulk chemistry but also in texture, microstructure, minor constituent mineralogy, and especially in calcareous, alkalialuminosilicate-free binder microchemistry. Based on a detailed literature survey on this debate and evaluation of all published results in light of this present comprehensive study, it is the author’s opinion that we are far from accepting even as a remote possibility of a “manmade” origin of pyramid stones. . .

To read the rest of the article, download a PDF of Jana's conference paper.

These webpages are best viewed with the newest version of your favorite web browser. The views and opinions expressed in this page are strictly those of the page author. The contents of this page have not been reviewed or approved by the University of Minnesota. Links on these pages to external websites are provided as a convenience, not an endorsement of either views expressed at or products promoted by those sites, so visit them at your own risk. Top photo: sunset over the excavations at Tell Mozan in northeastern Syria, taken by Ellery Frahm.

News articles come from various sources, and the sources are cited in each post. Excerpts from these articles are used under fair use. Use of this copyrighted material has not always been specifically authorized by the owner. The material has made available here in order to advance understanding of geoarchaeology, archaeological science, and related fields. This constitutes "fair use" of copyrighted material as described in section 107 of the US Copyright Law: "the fair use of a copyrighted work... for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research, is not an infringement of copyright." This material is distributed without fee or profit to those interested in it for research or educational purposes. This website is not commercial in any way -- it is nonprofit. There is no advertising on this website.

If you believe your work has been used here in a way that constitutes copyright infringement or your intellectual property rights have been otherwise violated, please provide the following information to the site author: 1. a description of the copyrighted work or intellectual property that you claim has been infringed; 2. a description of where that material is located on this site; 3. your address, telephone number, and email address; 4. a statement by you that you have a good faith belief that the disputed use is not authorized by the copyright owner, its agent, or the law; 5. a statement by you, made under penalty of perjury, that the above information in your notice is accurate and that you are the copyright or intellectual property owner or authorized to act on the copyright or intellectual property owner's behalf; and 6. your electronic or physical signature.

Main Page & CV

Obsidian Sourcing

Electron Microprobe Analysis in Archaeology

Petroarchaeology

Geo/Arch/Sci Blog

Geoarchaeology Funding

Everything Else

GEO/ARCH/SCI BLOG
GEOARCHAEOLOGY & ARCHAEOLOGICAL SCIENCE

Blog Author: Ellery Frahm