Did they build the pyramids with concrete?
Were the great Pyramids of Egypt built with blocks of concrete stones ? Concrete is re-agglomerated stone, a mixture of fragments of natural limestone with a binding substance.
The engineer Davidovits, author of important researches on the chemistry of materials and on polymeric reactions (cements, binders), started in 1975 a long study on the technologies, the mining and alchemical researches of the ancient Egyptians, with the aim of solving some of the so-called "Pyramids mysteries". In 1988 he collected his own considerations in the volume They have built the Pyramids, second edition in 1990, and in 2002 he published his book in French at the publisher Godefroy, with the title Ils ont bâti les Pyramids : a ponderous volume, in which it condenses its research and also responds to the controversies that have accompanied his theory over the time.
Davidovits theory is based on a series of archaeological evidences, and on the interpretation of some hieroglyphic texts that refer to the construction of gigantic monuments. No one has ever known how to give, until now, a definitive answer on how a civilization, which did not yet know the use of metals, could succeed to shape the hard stones with high precision and to lift huge blocks of limestone to the top of the pyramids, over 140 meters high. The observation that caused the greatest sensation a decade ago was the finding of organic fibers (hair?), together with air bubbles and bits of red colored plaster, inside a limestone block of the Great Pyramid.
In ancient Egypt, two distinct deities responsible for the creation of the world were venerated, two gods opposed to each other, each of whom knew its age of splendor. The first creator god was Khnum, revered by Cheops (so much so that the name of the god appears in the cartouche together with that of the Pharaoh, who called himself "Khnumu-Khufu"). He was the god of petrification, potters who did their work by agglomerating the clay, as well as the agglomeration of artificial stone, used for the pyramids. Khnum was considered the creator god from 3000 to 1800 BC .: it was believed that he kneaded humanity from the silt of the Nile, using the natron and the mafkàt. With such manipulations clay bricks were not produced, but a real "artificial stone".
The natron is a salt - sodium carbonate - which is found in Egypt in its natural state, in particular on the bottom and on the banks of some lakes. And the mafkat? It is a group of copper minerals (hydrated silicates, such as chrysocolla), of a light blue-green color, similar to turquoise, which the Egyptians extracted from the Sinai mines and which could be used as catalysts for the chemical reactions of "re-aggregation" of hard stones. In the deposits of copper minerals, there is a large quantity of minerals derived from the alteration of metal: sulphates, arsenates, phosphates and copper silicates. All are bluish or greenish in color.
The second demiurge was Amon, who imposed himself on the great cult 1500 years later (around 1600 BCE, at the time of the New Empire), venerated by Ramses II. He was the god of Upper Egypt, who created the world by carving it into living stone, the raw material for making temples and obelisks. For those two great religious currents, in competition with each other, the manipulation of the stone (which was matter regrouped or carved) was a sacred gesture, which repeated the act of the creation of man. The subject of the Gods, for the Egyptians, was stone, while for the Greeks it was gold (Krysós). This fact, according to Davidovits, also generated a misunderstanding, perpetuated over the centuries in the traditions of the Alchemists: they tried to regenerate the divine body, and regularly obtained stone, while they were convinced of having to obtain gold, because the Alexandrian culture, of a late Egypt by now inspired by Greek, had shifted the interpretative terms of their knowledge and their secrets.
Since ancient times, the research of minerals and their treatment with heat generated the processes of Alchemy. Such research naturally had to lead to the discovery of the conglomerate stone, or regenerated, before the melting of metals (since the first procedure requires a temperature lower than the second: the glazes can be obtained at temperatures of 600 ° -700 ° C, while the copper melts at 1083 ° C, or possibly a little lower, thanks to the use of "melting" substances such as natron). Therefore, the hypotheses of Davidovits are anything but ahistorical or incredible. A large number of "stone" vases, which are found in the tombs of ancient Egypt, appear to be made of very hard and extremely difficult stones: microgrès or metamorphic schist, anorthositic gneiss, andesite, basalt, breccia. Indestructible and mysterious objects, found in enormous quantities (tens of thousands). In the same materials, the ancient Egyptians molded statues, smoothed with a perfection that appears unattainable even with the use of modern techniques. Some objects worked in very hard stone are even prior to the extraction of suitable metals for their processing. Indeed, paradoxically, the processing of hard stone vases disappears at the time when bronze and iron instruments spread. To the use of metallic instruments, corresponds the processing of softer materials, such as alabaster, steatite, talc. Davidovits believes that the "hard stone" works are actually objects molded or worked on the lathe, with a recomposed lithic material, made of an inert and a binder, which was modeled like clay or clay. The final effect is that of a very hard stone, but the working of those vases - according to the elegant demonstration by Davidovits - was not done with drills and other sculpture tools, but with the tools and techniques typical of those who model and shape a plastic material, to then make it harden. Davidovits also reports the case of the sculptures of Akhenaton and Nefertiti, which belonged to the so-called "Mansùr collection". A series of subsequent surveys have declared the historical and archaeological authenticity of these sculptures, while others, apparently contradictory to the former, maintain that they are not carved in stone, but made with an artificial lytic surrogate, and perhaps even modeled on the mask of faces of the subjects represented. which corresponds exactly to the thesis supported by our author!
Davidovits identifies the following five steps in the progress of alchemical research:
- the discovery of enamel (linked to the discovery of copper in its minerals), ca. 4000 BC There are brilliant enamels made around 3800 BC
- the use for the self-enamelling of the caustic soda figurines, obtained from the natron-lime mixture, ca. 3600 BC
- the discovery of sodium silicate, ca. 3600 BC
- the agglomeration of the stone thanks to turquoise, used as a catalyst, approx. 3600 BC
- the agglomeration of aluminous limestones, for the construction of large blocks, with caustic soda (arch. Imhotep, "inventor" of the great pyramids), ca. 2700 BC
What are the tests given by Eng. Davidovits for his theory on the construction of the Pyramids? The nummulitic limestone of the Gizah plain, used to make the great pyramids, is a fossil stone. In the deposits of this rock, the tiny shells rest all "oriented", in the position they took when they settled at the bottom of the sea. In the blocks of the pyramids, on the other hand, their orientation is disordered, random, and denotes the use of pieces of limestone as "inert", in a re-aggregated mixture. The limestone of Gizah, according to Davidovits, is the most suitable stone for its "artificial recomposition". In fact it is tender and, macerated in water, it is easily disaggregated (the mass becomes a kind of mud, while the shells contained in it remain intact, like pebbles). In particular, it contains a small amount of "natural and reactive geo-polymeric ingredients", such as clay with kaolin, which is indispensable for the reaction with the caustic soda. This can be obtained by simply mixing the limestone sludge a little (1%) of natron (salt found in Egypt in its natural state) and some lime (2%). In the wake of the alchemical procedures used to make hard stone vases, it seems that the architect of Pharaoh Zoser, the famous Imhotep, who was later deified, discovered the way to "build" artificial stone blocks, exploiting the particular properties of Gizah limestone, mixed in the right proportions with the natron and the lime. The official titles that Imhotep boasted were: Chancellor of Lower Egypt, Prime Minister of the King of Upper Egypt, Administrator of the Grand Palace, Doctor, Hereditary Noble, Grand Priest of Anu (Heliopolis, for the Greeks), Pharaoh's Chief Architect Zoser, Sculptor and "manufacturer of stone vases". The author assumes that, in an attempt to reinforce and "stabilize" the raw clay bricks that were of general use for construction, Imhotep discovered the particular properties of the limestone mixture + kaolinitic clay + natron + lime, and exploited them for the construction of the stepped Pyramid of the Pharaoh Zoser, and then for those even more extraordinary of the Plain of Gizah.
Thus, in about twenty years the Pharaohs could well have made the two and a half million blocks of limestone, weighing between 2 and 30 tons each, necessary for the construction of the great pyramids. The blocks are well connected, so that their surfaces fit together perfectly (which seems obvious when you begin to think of blocks "cast in place", for which the blocks already made serve as formwork). The volume of the stones "made" in just forty years (forty million cubic meters of limestone) would have equaled that of the "quarried" stones and installed for the monuments of the following 1500 years. Many other considerations by Davidovits collaborate to support his theses: from the microclimate inside the pyramids, to the distribution of measurements and the size of the blocks on the different layers of the buildings. Of course, the most surprising elements are: the dimensions of Cheops's "sarcophagus", inside the King's Chamber of the Great Pyramid, the presence in the Valley of the Kings of a large sarcophagus in red syenite (now in the Louvre Museum), larger than the narrow entrance gorge to the Valley, and the presence in the Pyramids plain, in the funerary temples of Khefren and Menkaure (Micerino), of calcareous blocks of truly disproportionate size, 2-3 maters high and heavy up to 500 tons. Davidovits dismantles, one by one, the "proofs" of the supporters of the traditional theses, who would like the pyramids built by a myriad of men, anxious to drag blocks with wooden rollers on very long inclined ramps.
The blocks of the pyramids would instead consist of a 90-95% natural limestone with fossil shells, and a 5-10% of natural geological binders ("geo-polymeric" cements). A manufacturing technique very similar to that of our concrete, in which the caustic soda, obtained from the particular compositions of the minerals used (mafkat and natron), took the place of our blast furnace cement. Instead of 100,000 men, busy all day over a period of forty years, according to Davidovits' theories, 1,400 workers and twenty years of work to build the Great Pyramid would have sufficed; and the problem of "lifting the blocks" would no longer arise, since these would have been thrown into place, and the transport of the incoherent material can be carried out with sacks, baskets or other containers of all sorts. The problem of the manufacture of lime would remain, which the author elegantly solves with the observation that the ash of canes and papyrus is rich in calcium oxide (lime). He therefore assumes that, in the period of construction of the pyramids, the generalized collection of ashes was practiced, from all the bread ovens of all Egypt. Thus, 7,200 to 3,000 tons of lime could have been supplied per year. On the other hand, it is well known that the great vaults and domes of Antiquity were built using the concrete technique: we mention the examples of the Pantheon, the Basilica of Maxentius, the Hagia Sophia in Constantinople. The Romans, in particular, used mortars and concretes made with pozzolana, a rock of volcanic origin, which allowed them to build piers and port works able to withstand the chemical-physical aggression of the waters of the sea for centuries.
Davidovits also exposes the study of these cases, together with his hypotheses on the Pyramids of Egypt, in his rich website http://www.geopolymer.org/archaeo.
From the site it is also possible to download a video, made in France during 2002, which shows the experimental manufacture of some blocks of "limestone pyramid".
