Joseph Davidovits

Joseph Davidovits (born 23 March 1935) is a French materials scientist known for the invention of geopolymer chemistry. He posited that the blocks of the Great Pyramid are not carved stone but mostly a form of limestone concrete or man-made stone. He holds the Ordre National du Mérite.

Limestone concrete hypothesis

Davidovits believes that the blocks of the pyramid are not carved stone, but mostly a form of limestone concrete and that they were "cast" as with modern concrete. According to this hypothesis, soft limestone with a high kaolinite content was quarried in the wadi on the south of the Giza Plateau. The limestone was then dissolved in large, Nile-fed pools until it became a watery slurry. Lime (found in the ash of cooking fires) and natron (also used by the Egyptians in mummification) were 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 moulds and in a few days would undergo a chemical reaction similar to the curing of concrete. New blocks, he suggests, could be cast in place, on top of and pressed against the old blocks. Proof-of-concept tests using similar compounds were carried out at a geopolymer institute in northern France and it was found that a crew of five to ten, working with simple hand tools, could agglomerate a structure of five, 1.3 to 4.5 ton blocks in a couple of weeks. He also claims that the Famine Stele, along with other hieroglyphic texts, describe the technology of stone agglomeration.

Davidovits's method is not accepted by the academic mainstream. His method does not explain the granite stones, weighing well over 10 tons, above the King's Chamber, which he agrees were carved. Geologists have carefully scrutinized Davidovits's suggested technique and concluded his concrete came from natural limestone quarried in the Mokattam Formation.Harrell, James A. and Bret E. Penrod. 1993. "The Great Pyramid Debate -- Evidence from the Lauer Sample." Journal of Geological Education, vol. 41:358-363. However, Davidovits alleges that the bulk of the soft limestone came from the same natural Mokkatam Formation quarries found by geologists, and insists that ancient Egyptians used the soft marly layer instead of the hard layer to re-agglomerate stones.

Davidovits's hypothesis gained support from Michel Barsoum, a materials science researcher. Michel Barsoum and his colleagues at Drexel University published their findings supporting Davidovits's hypothesis in the ''Journal of the American Ceramic Society'' in 2006. Using scanning electron microscopy, they discovered in samples of the limestone pyramid blocks mineral compounds and air bubbles that do not occur in natural limestone.

More recently, another study has found the presence of carbon clusters of size ranging between 5 µm and 50 µm in samples of the Khufu pyramid that were identified with a nuclear microprobe and seem to indicate that the clusters are of organic origin. Their location in the pyramid samples coincide with the position of other clusters containing sodium. This situation is completely absent in limestone samples that were collected from stone in the limestone quarries of Tura and Maadi. The study concludes that “...all these observations fit with the model of construction created by Davidovits, who states that the blocks of the Khufu pyramid were cast ''in situ'' using granular limestone aggregates, natron, lime (probably produced by the combustion of wood in domestic fires) and water to produce an alkali alumino–silicate based binder.”

Dipayan Jana, a petrographer, made a presentation to the ICMA (International Cement Microscopy Association) in 2007 and gave a paper in which he discusses Davidovits's and Barsoum's work and concludes "we are far from accepting even as a remote possibility a 'man-made' origin of pyramid stones."

See also

* Great Pyramids of Giza
* Pyramids
* Egyptian pyramid construction techniques

Bibliography

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References

{{DEFAULTSORT:Davidovits, Joseph
1935 births
Living people
French Egyptologists
Johannes Gutenberg University Mainz alumni
French materials scientists