Giza Pyramids Made of Concrete?

I know, it sounds so low rent. Surely the pharaohs that built the pyramids at Giza in Egypt couldn’t have descended to something as rude and crude as concrete when they built their mausoleums?

But that is what John Noble Wilford reports in The New York Times. A team of researchers has taken samples of the interior of the pyramids and believe that some of the blocks of stone are in fact lime-based concrete. If true, it means that concrete was invented 2,500 years earlier than was thought.

Dr. Barsoum and his co-workers, Adrish Ganguly of Drexel and Gilles Hug of the National Center for Scientific Research in France, analyzed the mineralogy of samples from several parts of the Khufu pyramid, and said they found mineral ratios that did not exist in any known limestone sources. From the geochemical mix of lime, sand and clay, they concluded, “the simplest explanation” is that it was cast concrete.

But some people are not so happy about all this.

Zahi Hawass, secretary general of antiquities in Egypt and director of the Giza pyramids excavations, said in an e-mail message, “The idea that concrete was used is unlikely and completely unproven.”

Apparently the pyramid has been “restored and reinforced many times with the extensive use of concrete” so it’s possible that Barsoum and his collaborators were merely sampling more recent additions to the tombs.

Of course, it was only the outer casing that was built of pure white limestone. The inner casings were made of much rougher stuff. But concrete? Dahling, it’s so K-Mart!