This is the question we can find in the article by Colin Nickerson on New York Times.
http://www.nytimes.com/2008/04/23/world/africa/23iht-pyramid.1.12259608.html
"It is a theory that gives indigestion to mainstream archaeologists. Namely, that some of the immense blocks of the Great Pyramids of Egypt 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. Such an innovation would have saved millions of man-hours of grunting and heaving in construction of the enigmatic edifices on the Giza Plateau."
http://www.nytimes.com/2008/04/23/world/africa/23iht-pyramid.1.12259608.html
"It is a theory that gives indigestion to mainstream archaeologists. Namely, that some of the immense blocks of the Great Pyramids of Egypt 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. Such an innovation would have saved millions of man-hours of grunting and heaving in construction of the enigmatic edifices on the Giza Plateau."
See also:
Revisiting the construction of pyramids
