Linn W. Hobbs, a materials science professor at Massachusetts Institute of Technology, told The Boston Globe there is a chance ancient Egyptians could have cast the blocks from synthetic material instead of carving them from quarries. Scientists have long believed Romans were the first to use structural concrete.

Undergraduates in MIT's Materials in Human Experience class are building a scale-model pyramid made of quarried limestone and blocks cast from crushed limestone sludge fortified with clay, silica and natural desert salts.

Archaeologists say there is no evidence the pyramids are built of any synthetic material, the newspaper said. Hobbs said the concrete theory, advanced in the 1980s by French chemical engineer Joseph Davidovits, is fascinating because it would mean the ancient Egyptians were great materials scientists as well as great civil engineers.