Concrete Blocks Used in Great Pyramids Construction

Newswise — In partially solving a mystery that has baffled archeologists for centuries, a Drexel University professor has determined that the Great Pyramids of Giza are constructed with a combination of not only carved stones but the first blocks of limestone-based concrete cast by any civilization.

Michel Barsoum, professor of materials engineering, shows in a peer-reviewed paper published Dec. 1 in the Journal of the American Ceramic Society how the Egyptian builders of the nearly 5,000-year-old pyramids were exceptional civil and architectural engineers as well as superb chemists and material scientists. Barsoum wrote the paper with Adrish Ganguly, a an alumnus who received a doctoral degree in materials engineering from Drexel, and Gilles Hug of the National Center for Scientific Research in France.

Their conclusions could lead to a seismic shift in the kind of concrete used in construction and provide developing nations a way to build structures utilizing inexpensive and easily accessible materials.

The longstanding belief is that the pyramids were constructed with limestone blocks that were cut to shape in nearby quarries using copper tools, transported to the pyramid sites, hauled up ramps and hoisted in place with the help of wedges and levers. Barsoum argues that although indeed the majority of the stones were carved and hoisted into place, crucial parts were not. The ancient builders cast the blocks of the outer and inner casings and, most likely, the upper parts of the pyramids using a limestone concrete, called a geopolymer

To arrive at his findings, Barsoum, an Egypt native, and co-workers analyzed more than 1,000 micrographs, chemical analyses and other materials over three years. Barsoum, whose interest in the pyramids and geopolymers was piqued five years ago when he heard theories about the construction of the pyramids, says that to construct them with only cast stone builders would have needed an unattainable amount of wood and fuel to heat lime to 900 degrees Celsius.