The Surprisingly Plausible Theory that the Pyramids were Poured from Ancient Concrete

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The Great Pyramid of Khufu stands at 146 meters tall, weighs 6 million tons, and is composed of nearly 2.3 million granite and limestone blocks, weighing up to 80 tons each. Yet the structure is nearly perfectly level and square, the blocks so close-fitting that a piece of paper will not fit between them. And most astonishing of all, the work appears to have been completed in less than 20 years. How such precision construction on such a massive scale could be completed so quickly, by people possessing only bronze and stone age tools, is a question that has baffled Egyptologists for centuries. While the obvious answer is, of course, as ever, aliens, in 1974, a French geochemist named Joseph David Ovitz forwarded a radical new theory, that the pyramid blocks were not cut, but rather poured. To begin with, any theory explaining how the pyramids were built must contend with four basic problems. How the blocks were quarried and carved into shape, how the blocks were transported from the quarries to the construction site, how the blocks were raised to the upper levels of the pyramid, and finally, how the entire structure was kept square and level. Thanks to evidence left behind at ancient quarry sites like Aswan, ancient Egyptian stone cutting techniques are fairly well understood. Large stone blocks were hewn by first cutting a line of holes using a bow drill, into which were inserted wooden wedges. These wedges were then soaked in water, causing them to expand and fracture the stone. The rough cut block would be carved to shape using bronze chisels, and polished smooth using stone burnishers, the finished block being transported to the building site using barges sailing along the Nile. How the blocks were then moved from the river to the pyramid site itself, however, is a mystery. The traditional theory is that they were dragged on wooden sledges. But the only known depiction of this technique comes from the tomb of Diji-hu-ho-tep, a provincial governor who died around 1900 BC. A carving on the tomb wall depicts a giant stone statue of a man mounted on a sledge being pulled by 172 workers, while other workers pour water or oil on the ground to lubricate its path. While calculations have shown that the statue's weight would have been comparable to the Great Pyramid blocks, and that such a lubricated sledge would no trace of his statue has ever been found, nor has any other depiction of this technique. It is thus unknown whether the use of sledges to move heavy stone objects was ever a common practice. An alternate theory is that the ancient Egyptians used log rollers, which were continuously carried forward as the block rolled along. But this explanation presents a different problem. Based on the average rate of wear for such rollers, moving the 2.3 million blocks used in the Great Pyramid would have required so many trees that all of Egypt would have had to be deforested. The next problem is how the stones were lifted to the upper levels of the pyramid. Here, the traditional explanation has the Egyptians using giant ramps, either a single linear ramp or a spiral ramp winding around the outside of the pyramid. But both of these theories have serious flaws. A linear ramp would have required nearly as much stone as the pyramid itself, doubling the construction time and the material to be quarried. And a spiral ramp would In his chronicle of his travels through Egypt, the 5th century BCE Greek historian Herodotus describes a crane-like device used in the construction of stone monuments. But this account was written more than 2,000 years after the construction of the Great Pyramids of Giza, and no other evidence of such a device has ever been found. The final riddle of the pyramid's construction is how the whole structure was kept square and level. One theory posits that a trench was dug around the foundation of the pyramid and filled with water. The surface of which was then used as a guide for leveling the base. While certainly plausible, this does not account for the highly precise fit and alignment of all the blocks, as a carving error of even a fraction of a degree in a single block would have been amplified down to the row of stones, throwing off the alignment of the entire structure. Thus, given our current knowledge, nearly every accepted theory of the pyramid's construction suffers from at least one major flaw. And this is where Joseph David Overt enters the picture. Born in 1935, David Overt has an impressive résumé, holding a French degree in chemical engineering, a German PhD in chemistry, and a professorship of applied archaeology at Barry University and Penn State, and was made Chevalier de l'Ordre National de Méride by French President Jacques Chirac in 1998. When, in the early 1970s, David Overt turned his eye to the pyramids, he immediately noticed something strange. The limestone in the pyramid blocks did not match that of the quarries where they originated. Natural Egyptian limestone contains around 96-99% calcite and 0.5-2.5% quartz, dolomite, gypsum, and iron aluminosilicate, but the pyramid blocks contain only 85-90% calcite, as well as extra minerals such as opal, hydroxyl apatite, and silico aluminate. Furthermore, the microstructure of the stone is strangely amorphous or glass-like, with large numbers of tiny air bubbles not found in natural limestone. Stranger still, many of the blocks are oddly stratified, with large fossil fragments concentrated at the bottom and lighter grains at the top, rather than being distributed in alternating bands as in regular limestone. The final clue was a block found on the Giza Plateau that appeared to be composed of two different kinds of stone, one half of which had eroded faster than the other. From the evidence, David Overt drew an astonishing conclusion. The pyramid blocks are not composed of natural limestone, but rather a reconstituted geopolymer, a type of ancient Egyptian concrete. According to David Overt's theory, the blocks were not quarried and transported to Giza, but rather cast in place in wooden moulds. This would account for the extreme precision of the pyramid's construction, as the initial liquid state of the limestone concrete would have made the blocks self-leveling and allowed for extremely thin seams between blocks. This technique was also ideal for use on the Giza Plateau, which has abundant supplies of soft, crumbly limestone otherwise unsuited to large-scale construction. In his laboratory, David Overt succeeded in creating a reconstituted limestone concrete using only four ingredients that were readily available to the ancient Egyptians – water, crushed limestone, quicklime, and natron, a mixture of salt and sodium bicarbonate found on the banks of the Nile and widely used in mummification. When David Overt sent out samples of his lab-made concrete for blind analysis, along with pieces of actual pyramid stone, every laboratory reported that the two samples were identical in composition. The result appeared definitive – David Overt had finally cracked the age-old riddle of how the pyramids were built. In 1988, he published his results in a book titled The Built of the Pyramids. Yet, despite the chemical evidence backing his theory, it immediately attracted overwhelming scorn and hostility from mainstream Egyptologists. Among David Overt's greatest critics is Zahi Hawass, former Egyptian Minister of State for Antiquities Affairs, who of the theory stated, It's highly stupid. The pyramids are made from solid blocks of quarried limestone. To suggest otherwise is idiotic and insulting. Many geologists were also dismissive of the theory. With a 2007 study by Dipayan Janna of Columbia University, the contrary to David Overt's claims, the pyramid-casing blocks are in fact chemically and geologically identical to natural limestone quarried at Tura and other sites, and distinct from David Overt's lab-made geopolymer. In turn, David Overt accused Janna of not analyzing an actual pyramid stone, while in 2006, an analysis by Michel W. Barsoom of Philadelphia Drexel University independently confirmed that the pyramid and quarry stones were geologically distinct. And the debate rages on. David Overt himself admits that there are still several gaps in his hypothesis, such as the 8,000 tons of granite blocks used to construct the core of the pyramid. These match stone from the quarries in Aswan, and unlike the limestone, would have had to have been cut and moved by hand. But as this stonework only accounts for 0.3% of the pyramid's weight, it does not preclude the use of cast limestone to expedite the rest of the structure's construction. Also missing is any evidence of the infrastructure required to mix such vast quantities of concrete. But as the village that housed the pyramid's construction force was only discovered in 1988, David Overt is confident that this evidence will eventually emerge. For now, however, his ideas remain on the fringes of archaeological discourse, naturally secondary to the more widely accepted theory of those ancient aliens. Don't forget to subscribe, and thank you for watching!