Scientist Says Concrete Was Used in Pyramids

http://tinyurl.com/y5po98 (nytimes.com)

"In new research on the Great Pyramids of Giza, a scientist says he has found more to their construction than cut natural limestone. Some original parts of the massive structures appear to be made of concrete blocks.If true, historians say, this would be the earliest known application of concrete technology, some 2,500 years before the Romans started using it widely in harbors, amphitheaters and other architecture.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. They used concrete blocks, he said, on the outer and inner casings and probably on the upper levels, where it would have been difficult to hoist carved stone."

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http://english.sabah.com.tr/5DCB215B618A40198B165FF09594FD6C.html
"According to a French science magazine called "Science and Life", scientists have noticed the difference between the stones in pyramids and stones in stone quarries. Drexel University Professor Michel Barsoum and France National Aviation Research Office manager Gilles Hug told that there are distnictive differences between the stones of Giza Pyramids and the stones in the quarries which were thought to be the source of the stones. Researchers think that the stones in pyramids are geo-polymer based synthetics."

http://www.timesonline.co.uk/article/0,,13509-2480751,00.html

This article looks at some of the arguments for and against: "Opponents of the theory dispute the scientific evidence. They also say that the diverse shapes of the stones show that moulds were not used. They add that a huge amount of limestone chalk and burnt wood would have been needed to make the concrete, while the Egyptians had the manpower to hoist all the natural stone they wanted. The concrete theorists say that they will be unable to prove their theory conclusively until the Egyptian authorities give them access to substantial samples."

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