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Joseph Davidovits (born 23 March 1935) is a French materials scientist known for the invention of geopolymer chemistry. He posited that the blocks of the Great Pyramid are not carved stone but mostly a form of limestone concrete or man-made stone.
Davidovits believes that the blocks of the pyramid are not carved stone, but mostly a form of limestone concrete and that they were "cast" as with modern concrete. [1] According to this hypothesis, soft limestone with a high kaolinite content was quarried in the wadi on the south of the Giza Plateau. The limestone was then dissolved in large, Nile-fed pools until it became a watery slurry. Lime (found in the ash of cooking fires) and natron (also used by the Egyptians in mummification) were mixed in. The pools were then left to evaporate, leaving behind a moist, clay-like mixture. This wet "concrete" would be carried to the construction site where it would be packed into reusable wooden moulds and in a few days would undergo a chemical reaction similar to the curing of concrete. New blocks, he suggests, could be cast in place, on top of and pressed against the old blocks. Proof-of-concept tests using similar compounds were carried out at a geopolymer institute in northern France and it was found that a crew of five to ten, working with simple hand tools, could agglomerate a structure of five, 1.3 to 4.5 ton blocks in a couple of weeks. [2] He also claims that the Famine Stele, along with other hieroglyphic texts, describe the technology of stone agglomeration.
Davidovits's method is not accepted by the academic mainstream. His method does not explain the granite stones, weighing well over 10 tons, above the King's Chamber, which he agrees were carved. Geologists have carefully scrutinized Davidovits's suggested technique and concluded his concrete came from natural limestone quarried in the Mokattam Formation. [3] However, Davidovits alleges that the bulk of the soft limestone came from the same natural Mokkatam Formation quarries found by geologists, and insists that ancient Egyptians used the soft marly layer instead of the hard layer to re-agglomerate stones.
Davidovits's hypothesis gained support from Michel Barsoum, a materials science researcher. [4] Michel Barsoum and his colleagues at Drexel University published their findings supporting Davidovits's hypothesis in the Journal of the American Ceramic Society in 2006. Using scanning electron microscopy, they discovered in samples of the limestone pyramid blocks mineral compounds and air bubbles that do not occur in natural limestone. [5]
Dipayan Jana, a petrographer, made a presentation to the ICMA (International Cement Microscopy Association) in 2007 [6] and gave a paper [7] in which he discusses Davidovits's and Barsoum's work and concludes "we are far from accepting even as a remote possibility a 'man-made' origin of pyramid stones."
A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel (aggregate) together. Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete. Concrete is the most widely used material in existence and is behind only water as the planet's most-consumed resource.
The Great Pyramid of Giza is the largest Egyptian pyramid and served as the tomb of pharaoh Khufu, who ruled during the Fourth Dynasty of the Old Kingdom. Built c. 2600 BC, over a period of about 27 years, the pyramid is the oldest of the Seven Wonders of the Ancient World, and the only wonder that has remained largely intact. It is the most famous monument of the Giza pyramid complex, which is part of the UNESCO World Heritage Site "Memphis and its Necropolis". It is situated at the northeastern end of the line of the three main pyramids at Giza.
A pyramid is a structure whose visible surfaces are triangular and converge to a point at the top, making the shape roughly a pyramid in the geometric sense. The base of a pyramid can be of any polygon shape, such as trilateral or quadrilateral
The pyramid of Djoser, sometimes called the Step Pyramid of Djoser, is an archaeological site in the Saqqara necropolis, Egypt, northwest of the ruins of Memphis. It is the first pyramid to be built. The 6-tier, 4-sided structure is the earliest colossal stone building in Egypt. It was built in the 27th century BC during the Third Dynasty for the burial of Pharaoh Djoser. The pyramid is the central feature of a vast mortuary complex in an enormous courtyard surrounded by ceremonial structures and decoration.
Stonemasonry or stonecraft is the creation of buildings, structures, and sculpture using stone as the primary material. Stonemasonry is the craft of shaping and arranging stones, often together with mortar and even the ancient lime mortar, to wall or cover formed structures.
The Great Sphinx of Giza is a limestone statue of a reclining sphinx, a mythical creature with the head of a human and the body of a lion. Facing directly from west to east, it stands on the Giza Plateau on the west bank of the Nile in Giza, Egypt. The face of the Sphinx appears to represent the pharaoh Khafre. The original shape of the Sphinx was cut from the bedrock, and has since been restored with layers of limestone blocks. It measures 73 m (240 ft) long from paw to tail, 20 m (66 ft) high from the base to the top of the head and 19 m (62 ft) wide at its rear haunches.
Portland stone is a limestone geological formation dating to the Tithonian age of the Late Jurassic that is quarried on the Isle of Portland in Dorset, England. The quarries are cut in beds of white-grey limestone separated by chert beds. It has been used extensively as a building stone throughout the British Isles, notably in major public buildings in London such as St Paul's Cathedral and Buckingham Palace. Portland stone is also exported to many countries, being used for example at the United Nations headquarters in New York City.
The Egyptian pyramids are ancient masonry structures located in Egypt. Sources cite at least 118 identified "Egyptian" pyramids. Approximately 80 pyramids were built within the Kingdom of Kush, now located in the modern country of Sudan. Of those located in modern Egypt, most were built as tombs for the country's pharaohs and their consorts during the Old and Middle Kingdom periods.
The pyramid of Khafre or of Chephren is the middle of the three Ancient Egyptian Pyramids of Giza, the second tallest and second largest of the group. It is the tomb of the Fourth-Dynasty pharaoh Khafre (Chefren), who ruled c. 2558−2532 BC.
The Giza pyramid complex in Egypt is home to the Great Pyramid, the Pyramid of Khafre, and the Pyramid of Menkaure, along with their associated pyramid complexes and the Great Sphinx. All were built during the Fourth Dynasty of the Old Kingdom of ancient Egypt, between c. 2600 – c. 2500 BC. The site also includes several temples, cemeteries, and the remains of a workers' village.
Egyptian pyramid construction techniques are the controversial subject of many hypotheses. These techniques seem to have developed over time; later pyramids were not constructed in the same way as earlier ones. Most of the construction hypotheses are based on the belief that huge stones were carved from quarries with copper chisels, and these blocks were then dragged and lifted into position. Disagreements chiefly concern the methods used to move and place the stones.
The pyramid complex of Userkaf was built c. 2490 BC for the pharaoh Userkaf, founder of the 5th Dynasty of Egypt. It is located in the pyramid field at Saqqara, on the north-east of the step pyramid of Djoser. Constructed in dressed stone with a core of rubble, the pyramid is now ruined and resembles a conical hill in the sands of Saqqara. For this reason, it is known locally as El-Haram el-Maharbish, the "Heap of Stone", and was recognized as a royal pyramid by western archaeologists in the 19th century.
Cast stone or reconstructed stone is a highly refined building material, a form of precast concrete used as masonry intended to simulate natural-cut stone. It is used for architectural features: trim, or ornament; facing buildings or other structures; statuary; and for garden ornaments. Cast stone can be made from white and/or grey cements, manufactured or natural sands, crushed stone or natural gravels, and colored with mineral coloring pigments. Cast stone may replace such common natural building stones as limestone, brownstone, sandstone, bluestone, granite, slate, coral, and travertine.
Cement clinker is a solid material produced in the manufacture of portland cement as an intermediary product. Clinker occurs as lumps or nodules, usually 3 millimetres (0.12 in) to 25 millimetres (0.98 in) in diameter. It is produced by sintering limestone and aluminosilicate materials such as clay during the cement kiln stage.
The stone quarries of ancient Egypt once produced quality stone for the building of tombs and temples and for decorative monuments such as sarcophagi, stelae, and statues. These quarries are now recognised archaeological sites. Ancient quarry sites in the Nile valley accounted for much of the limestone and sandstone used as building stone for temples, monuments, and pyramids. Eighty percent of the ancient sites are located in the Nile valley; some of them have disappeared under the waters of Lake Nasser and some others were lost due to modern mining activity.
Geopolymers are inorganic, typically ceramic, alumino-silicate forming long-range, covalently bonded, non-crystalline (amorphous) networks. Obsidian fragments are a component of some geopolymer blends. Commercially produced geopolymers may be used for fire- and heat-resistant coatings and adhesives, medicinal applications, high-temperature ceramics, new binders for fire-resistant fiber composites, toxic and radioactive waste encapsulation and new cements for concrete. The properties and uses of geopolymers are being explored in many scientific and industrial disciplines: modern inorganic chemistry, physical chemistry, colloid chemistry, mineralogy, geology, and in other types of engineering process technologies. The field of geopolymers is a part of polymer science, chemistry and technology that forms one of the major areas of materials science.
The pyramid of Senusret I is an Egyptian pyramid built to be the burial place of the Pharaoh Senusret I. The pyramid was built during the Twelfth Dynasty of Egypt at el-Lisht, near the pyramid of his father, Amenemhat I. Its ancient name was Senusret Petei Tawi.
Geopolymer cement is a binding system that hardens at room temperature.
The Sphinx water erosion hypothesis is a fringe claim, contending that the Great Sphinx of Giza and its enclosing walls eroded primarily due to ancient floods or rainfalls, attributing their creation to Plato's lost civilization of Atlantis over 11,500 years ago.
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