The Concrete Pyramid Theory
Posted on December 4, 2006A Times Online article discusses an alternative theory to the idea that the Ancient Egyptians carried huge stone blocks from a far off quarry to build the pyramids. The concrete theory suggests that a limestone slurry was used to make many of the stones used in the ancient pyramids.
But according to Professor Gilles Hug, of the French National Aerospace Research Agency (Onera), and Professor Michel Barsoum, of Drexel University in Philadelphia, the covering of the great Pyramids at Giza consists of two types of stone: one from the quarries and one man-made.The scientists are not saying that all the blocks are made this way but that the blocks near the top are. They argue that these blocks have a different density then the blocks at the bottom of the pyramids. The Times article says the scientists will not be able to prove their theory unless the Egyptian authorities give them access to samples. The concrete theory is also known as the Davidovits theory because Joseph Davidovits, a French chemist, first came up with the idea in 1970. This Wikipedia entry points to a couple other articles on Davidovits' theory located here, here and here.
"There's no way around it. The chemistry is well and truly different," Professor Hug told Science et Vie magazine. Their study is being published this month in the Journal of the American Ceramic Society.
The pair used X-rays, a plasma torch and electron microscopes to compare small fragments from pyramids with stone from the Toura and Maadi quarries.
They found "traces of a rapid chemical reaction which did not allow natural crystalisation . . . The reaction would be inexplicable if the stones were quarried, but perfectly comprehensible if one accepts that they were cast like concrete."