The idea that some pyramid blocks were cast of concrete-like material was aggressively advanced in the 1980s by the French chemical engineer Joseph Davidovits, who argued that the Giza builders had pulverized soft limestone and mixed it with water, hardening the material with natural binders that the Egyptians are known to have used for their famous blue-glaze ornamental statues.
Such blocks, Davidovits said, would have been poured in place by workers hustling sacks of wet cement up the pyramids - a decidedly less spectacular image than the ones popularized by Hollywood epics like "The Ten Commandments," with thousands of near-naked toilers straining with ropes and rollers to move mammoth carved stones.
"That's the problem, the big archaeologists - and Egypt's tourist industry - want to preserve romantic ideas," said Davidovits, who researches ancient building materials at the Geopolymer Institute in St. Quentin.
