Did the Great Pyramids' builders use concrete?

[Primus Pilus]

It is a theory that gives indigestion to mainstream archaeologists. Namely, that some of the immense blocks of the Great Pyramids of Egypt 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.

 

Such an innovation would have saved millions of man-hours of grunting and heaving in construction of the enigmatic edifices on the Giza Plateau.

 

"It could be they used less sweat and more smarts," said Linn Hobbs, professor of materials science at the Massachusetts Institute of Technology.

 

Int. Herald Tribune

[Faustus]

"It could be they used less sweat and more smarts," said Linn Hobbs, professor of materials science at the Massachusetts Institute of Technology.

Int. Herald Tribune

But would it? Converting all that limestone to lime to make concrete by burning after crushing (per Davidot), or some other process, then transporting it to the site and "forming" the blocks in locations ever more limited in accessibility, means a variety of materials and skills have to flow to the operation rather than being individually fabricated offsite. Forming concrete is no easy task, even with modern forming materials like plywood. It takes extremely well braced forms with good support in four lateral directions to hold the amount of concrete being either poured or mixed within the forms.

 

If no bulk aggregates were included then the Roman method of compacting the concrete in place to strengthen and remove excess water would not seem to reduce the lateral forces in the forms either. The Roman construction sites were well managed in that regard: always building up the wooden forms as concrete was added and compacted into the mix below. And they added foreign material (rubble) as aggregate fill to their concrete allowing for less actual concrete mix in the forms. This aggregate material would act as a stabilizer to the lateral forces.

 

If forming was used and then the outside faces were

[Doug Weller]

Barsoum is good at getting publicity, the author of the article is not good at researching what he's writing.

To quote a geologist friend:

 

The original geopolymer crowd seemed to have a whole litany of colloquial explanations for natural geological features... crossbedding was packing & settling lines that formed as the cement was pored/packed into the molds, solution vugs were air bubbles in the cement, or if all else failed the offending masonry was just a replacement block of natural limestone that was used to repair damage, etc. etc. This was coming from people who claimed through petrographic and X-ray analysis that there was a whole array of exotic minerals in the limestone that when other qualified researchers looked at the same specimen could not find any of them. What they did find was typical of a natural limestone (as well as an ancient whitewash coating on one of the surfaces) with bedding lamella and a calcite veinlet in the bulk limestone. When this was pointed out it was declared by the geopolymer crowd that the qualified researchers did not understand the geopolymer theory properly, they did not know how to analyze the samples properly, they were part of a demeaning stand against the geopolymer researchers and their scientific theory, etc. Here is a summary of the analysis against the geological claims of geopolymer theory:

 

7mb Pdf file:

http://www.cmc-concrete.com/CMC%20Publications/2007,%20The%20Great%20Pyramid%20Debate,%2029th%20ICMA.pdf

 

Jana, D. (2007) The Great Pyramid Debate: 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. Proceedings of the Twenty-Ninth Conference on Cement Microscopy Quebec City, PQ, Canada May 20 -24, 207-266.

[Faustus]

Jana, D. (2007) The Great Pyramid Debate: 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. Proceedings of the Twenty-Ninth Conference on Cement Microscopy Quebec City, PQ, Canada May 20 -24, 207-266.

 

A direct link to PDF HERE (Davidovits)

Edited April 25, 2008 by Faustus