A new angle on pyramids: Scientists explore whether Egyptians used concrete

The Boston Globe reports:

It's a theory that gives indigestion to mainstream archeologists. Namely, that some of the immense blocks of Egypt's Great Pyramids 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.
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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 W. Hobbs, professor of materials science at Massachusetts Institute of Technology. "Maybe the ancient Egyptians didn't just leave us mysterious monuments and mummies. Maybe they invented concrete 2,000 years before the Romans started using it in their structures."

That's a notion that would dramatically change engineering history. It's long been believed that the Romans were the first to employ structural concrete in a big way, although the technology may have come from the Greeks.

A handful of determined materials scientists are carrying out experiments with crushed limestone and natural binding chemicals - stuff that would have been readily available to ancient Egyptians - designed to show that blocks on the upper reaches of the pyramids may have been cast in place from a slurry poured into wooden molds.

These researchers at labs in Cambridge, Philadelphia, and St. Quentin, France, are trying to demonstrate that Egyptians of about 2,500 BC could have been the true inventors of the poured substance that is humanity's most common building material - used in everything from Rome's Pantheon to Boston's Big Dig.