limestone concrete

Davidovits suggested that the blocks were molded in place by using a form of limestone concrete.

A recent though unpopular theory proposes that the building blocks were manufactured in-place from a kind of "limestone concrete".

He posited that the blocks of the Great Pyramid are not carved stone but mostly a form of limestone concrete or man-made stone.

Materials scientist Joseph Davidovits has claimed that the blocks of the pyramid are not carved stone, but mostly a form of limestone concrete and that they were "cast" as with modern concrete.

Reporting the results of his study, Michel W. Barsoum, a professor of materials engineering at Drexel University in Philadelphia, concluded that the use of limestone concrete could explain in part how the Egyptians were able to complete such massive monuments, beginning around 2550 B.C.

Although his ideas are not accepted by mainstream Egyptologists, in December 2006 Michel Barsoum, Adrish Ganguly, and Gilles Hug published a peer-reviewed paper in the Journal of the American Ceramic Society stating that parts of the pyramid were cast with a type of limestone concrete.