To sum-up: Alkali-Activated Materials (AAM) are NOT Polymers, so they cannot be called Geo-Polymers. AAMs are hydrates and Geopolymers are polymers. Geopolymers are NOT a subset of AAM because they are not a calcium hydrate alternative (no NASH, no KASH). Geopolymer is not a hydrate, because water does not participate in the structuration of the material. AAM and Geopolymers belong to two very different and separate chemistry systems (a hydrate/precipitate that is a monomer or a dimer versus a true polymer). Those who claim that both terms are synonyms are promoting a misleading scientific belief. Learn why by watching these four videos.
“Non-activated geopolymers” are the only TRUE geopolymers that provide the excellent properties you are expecting. AAM kills polymeric reaction.

Get an official transcript of the 4 videos, including a DOI for official references and citations, by downloading the technical paper # 25.

Geopolymers vs. AAM: Understanding the Crucial Differences

33 min, 89 MB. Click on the CC icon to ACTIVATE SUBTITLES. Watch it fullscreen.

Buy the “Geopolymer Bundle” Video + Tutorial (click here).

Summary: Geopolymers are not Alkali Activated Materials (AAM).
AAMs are characterized by their hydration process and are not polymers. Therefore, they cannot be called geopolymers. Geopolymers, on the other hand, are polymers and not hydrates. Consequently, the terms NASH or KASH are irrelevant because geopolymers are polymers, not hydrates. It is a significant scientific error to claim that polymers and hydrates are similar. Attempting to create a polymer using the mix design of a hydrate will result in failure (cracking, shrinkage and efflorescence). Conversely, following the kinetics of a polymer when making a geopolymer will result in success.
There is no controversy. You have been misled by people who lack a proper understanding of polymers. You have been faithfully following and copying their wrong mixes and getting bad results.
Everything is proven with solid scientific evidence against fake science.

Video description: This video is an excerpt from a 3-hour workshop on geopolymer processing. Buy the Geopolymer Bundle (click here).
It addresses common misconceptions about geopolymer cements and explains why many attempts to produce geopolymer cements have failed to achieve the superior properties that are often cited in the scientific literature.
The presenters argue that geopolymers are not alkali activated materials (AAM) and highlight the fundamental differences between the two. They emphasize the importance of understanding polymer chemistry for successful formulation.
The video critiques common errors in the scientific literature, particularly those propagated between 2003 and 2019, that have led to confusion in the field. It explains why treating geopolymers as hydrates (NASH or KASH) is incorrect and provides evidence from infrared spectroscopy and the role of water to support this claim.
The presenters emphasize the importance of proper terminology and understanding, pointing out that geopolymers are true mineral polymers, not hydrates or precipitates.
This informative video aims to clear up misconceptions and provide a solid foundation for those interested in working with geopolymer cement, ultimately promoting a better understanding and more successful implementation of this innovative material in construction and engineering.

Chapters:

• 00:00 Introduction
• 01:33 AAM are not GP
• 03:53 Geopolymer definition
• 05:06 Example of wrong mixing
• 11:58 Portland cement chemistry
• 12:57 Geopolymer chemistry
• 14:05 Wrong NASH and KASH terminology
• 15:42 Wrong RILEM committee definition
• 17:09 Water to binder ratio proves GP not a hydrate
• 18:35 IR proves GP not a hydrate
• 24:49 AAM are not Polymers
• 25:18 What is activation?
• 27:47 There is no GP activator
• 29:00 Concrete Society classifications
• 30:15 Designing Buildings definitions
• 32:43 GP is a polymer not a hydrate

Other videos

In his four recent keynotes at the Geopolymer Camp 2014, Geopolymer Camp 2015, Geopolymer Camp 2016 and Geopolymer Camp 2017, Prof. J. Davidovits explained why Alkali-Activated-Materials are not Geopolymers, or why alkali-activation is not geopolymerization. We have selected all the sequences that had been dedicated to this issue in the GPCamp-2014, 2015, 2016 and 2017 keynotes. These new videos are titled: Why Alkali-Activated Materials are NOT Geopolymers. You will finally understand why they are two different systems.

Part 4 (new 2017): NASH / KASH is an invalid terminology

In 2016, a paper published by a group of scientists determined that there is no presence of NASH or KASH in geopolymer cement (see part 3 below). In this short excerpt, Prof. Joseph Davidovits explains this result by the true polymer nature of geopolymer chemistry. You will learn what true NASH and KASH are, and in which context they are actually used. AAM and geopolymer cement (wrongly shorten by some as “geopolymers”) are two very different and separate chemistry (a hydrate/precipitate that is a monomer or a dimer versus a true polymer). None is a subset of the other or its derivative which leads to confused interpretations.

10 min, 26 MB. Click on the icon on the right to watch it fullscreen.

Part 3: AAM are not polymers, so they cannot be called “geopolymers”

Prof. Joseph Davidovits emphasizes the fact that Alkali Activated Materials (AAM) are not polymers, so they cannot be called “geopolymers”. He presents what scientists are now writing about this issue. They now agree with proven facts that it is a big scientific mistake to use AAM and geopolymer as synonyms, and people shall stop doing so. Geopolymer cement is not a CSH derivative; therefore, scientists are now stating that applying the CSH terminology from Portland cement is not only inappropriate, but also calling them NASH and KASH is totally wrong. Those who purposefully use and propagate these misleading languages delude the understanding of the true chemical reactions that really occur (never a hydrate or a gel, but a polymer), resulting in confused interpretations.

27 min, 62 MB. Click on the icon on the right to watch it fullscreen.

Part 1 (2014): AAM are not geopolymers, two different chemistries

Prof. J. Davidovits explains the main differences between AAC (Alkali-Activated Cement or Concrete), AAS (Alkali-Activated Slag), AAF (Alkali-Activated Fly Ash) and Slag-based Geopolymer cement, in terms of chemistry, molecular structure, long-term durability. In a second part, on hand of the industrialization of Slag/fly ash-based geopolymer cement/concrete implemented by the company Wagners, Australia, he focuses on the results provided by the carbonation testing data obtained for ordinary Portland cement, AAS and EFC (Slag/fly ash-based geopolymer). The tests were carried out at the Royal Melbourne Institute of Technology RMIT in Australia. Geopolymer behaves like regular Portland cement, whereas AAS gets very bad carbonation results.

20 min, 46 MB. Click on the icon on the right to watch it fullscreen.

Part 2 (2015): Clarifying statement about all the false ideas and assertions

Prof. J. Davidovits makes a clarifying statement about all the false ideas and assertions written by several alkali activated materials scientists (incorrectly using the word “geopolymer” for marketing purpose in place of AAM) and blindly imitated by others. He explains why it is a true polymer with a well-known and understood chemistry (as opposed to those who claim it is a “gel” of unknown character), mentions the historicity and discovery of geopolymer chemistry, the real contributions of Glukhovsky and what he really wrote about geopolymers. He develops the range of actual industrial applications that goes far beyond cement made out of wastes…

29 min, 67 MB. Click on the icon on the right to watch it fullscreen.

The theory has many supporters around the world, but there are still opponents criticizing and repeating the same arguments. This page is here to help supporters counter critics.

First, you find below a list of the main opposing ideas, opinions and sometimes evidence, and how to reply to them. Then, we expose an extended abstract of the theory with a simplify list of arguments.

More details, information, videos are available at this page. Only a lengthy summary is disclosed here.

List of the main opposing arguments

1- The context. What you need to keep in mind.

An hypothesis that has a long life.

The theory is now well-known by the public since 1988 (first publication of the book in english), but presented earlier in official egyptology congresses since 1979. The Geopolymer Institute website exists since 1996 and, since the beginning, the theory was exposed in detail. Since then, new scientific papers, new books, new videos, new webpages have been published with the latest updates. Nevertheless, most opponents are always expressing their opinions based on hearsays, preconceived ideas, clichés, and are not taking 10 minutes of their precious time to read what is presented here. Some of them are publishing rebuttals using “wrong” arguments that Davidovits’ has never raised instead of quoting his work (for example, we do not claim to crush stones as aggregates, a useless exhausting effort, but instead asserting the use of weathered or eroded stones). A parody of science since some studies were made on “fake” pyramid samples. See section #5 below and the page: Deep misleading publications by geologists. These published sloppy papers are taken for serious references by the opponents of the re-agglomerated theory. You will be disappointed by the fact that this misleading behavior represents the vast majority of the opponents. Why? Because the artificial stone theory is the truth, they don’t know how to counter it. They are missing the big picture.

A global thinking

People trying to solve the Pyramids mysteries are always thinking in terms of engineering and technique, and worse, they are only focusing on Kheops’ pyramid, forgetting the previous ones and the hundred more built after. If an idea sounds valid for Kheops, it is immediately invalid for the others. Davidovits’ theory is the only theory with a global view encompassing the building of all the pyramids of Egypt for 250 years, from the first of Zoser to those in crude bricks, with solid and valid scientific evidence in geology, mineralogy, chemistry, hieroglyphic studies, religion and Egyptian history… Read the extended abstract below or buy the book to learn more. No other theory has this global approach.

Official theory

The man-made or re-agglometared stone theory exists, is still discussed and countered for more than 40 years! If the arguments against are so easy to expose, to denigrate and are self-evident, why people are still talking about it? Why people are still not convinced by carving theories?

By the way, what is the official theory? Ask the opponents before starting the discussion. The bare truth is that there is none. After centuries, so many studies, scientific investigations, archeological discoveries, carving theories are still a weak hypothesis. Nobody agrees on the main scenario around carving and hoisting. None is approved by the mainstream. What a massive failure after more than one century of egyptology! When someone raises a solution, it lasts 6 months up to 1 year after it vanishes because it leads to other insoluble problems. And the artificial stone theory is there for more than 40 years. After so much time, the carving theories fail !

So, the opponent of the re-agglomation hypothesis believes he acts in the name of truth, when actually he is found defending one of the many unofficial speculative carving theories! Is he convincing? Not at all. It is easy to criticize that his (un)official theory brings up more problems than solutions, and, above all, where is the evidence?

The ultimate evidence

Here is the solid argument that everybody understands:

More and more scientists agree and support the theory. Classical methods of investigation are not relevant. They cannot make a difference between a natural and a synthetic mineral.

Several studies, carried out by independent scientists using the most modern equipment, exposed the ultimate proofs that the pyramids blocks are not natural. You may find various papers or opinions challenging the theory, but all prefer ignoring these independent analysis. Believing in the artificial stone theory, or countering it, is simply no longer relevant. It has become a fact, a truth that is still fought by some people for irrational purposes.

2- There is stone everywhere. Why bother to make a concrete?

This is common sense, isn’t it? You are thinking of the use of stones with a modern mind, in terms of architecture. For 3000 years long, Egyptians used stones (whether man-made or carved) only for religious purposes: temples, tombs and statues. Where are the houses, where are the palaces, where are the garrisons? They were built in crude bricks. During the pyramids time, it was forbidden to carve stones. Man-made stone bears a specific religious meaning related to the creation of life. Read more about this topic in the extended abstract under the “Religious context“.

If it is not convincing enough:

Recent scientific studies using very powerful and modern equipment found the ultimate evidence that the pyramids stones are synthetic. Believing in the artificial stone theory, or countering it, is simply no longer relevant. It has become a fact, a truth.

3- We see fossil shells, so it is a natural stone.

Man-made stone holds around 90% of natural mineral aggregates (here nummulites, fossil shells), and between 5 to 10% of the synthetic geopolymer binder. Some opponents believe that we claim that the geopolymer chemistry is manufacturing fossil shells in situ, which is absurd. But where do the fossil shells come from? From the quarry where we extract the natural stone aggregates. It is like claiming modern concrete is a carved and natural stone because it contains natural sand and natural stone aggregates ! If the stones were carved, why are all shells intact? Why none of them are cut?

There is evidence that limestone blocks come from different quarries. Since we know their origin, without a doubt, the stones are natural? But to make re-agglomerated limestone concrete, it is necessary that the 90% of limestone aggregate come from somewhere. Of course, they come from the same place! So, people have 90% of chance of analyzing a natural aggregate (here, nummulite fossil shell) and stating the artificial stone theory is wrong, setting aside the 10% synthetic binder.

If it is not convincing enough:

Recent scientific studies using very powerful and modern equipment found the ultimate evidence that the pyramids stones are synthetic. Believing in the artificial stone theory, or countering it, is simply no longer relevant. It has become a fact, a truth.

4- If it is a concrete-like stone, all block would have the same dimensions. But they are all different.

Before the first pyramid built out of stone, the ancient Egyptians constructed very imposing crude brick monuments. We find large funerary temple enclosures of the second dynasty, like the Khasekhemwy one (2,730 B.C.). Its massive wall is of crude clay bricks, therefore in a molded material. It is generally agreed, since these bricks were worked in molds, that their dimension must be uniform. However, this is wrong. Despite having been manufactured in molds, the clay bricks are of approximately 5 different sizes, implying the use of several patterns. We find these differences in proportions in all pyramids. This heterogeneity gives the monuments the ability to resist earthquakes by avoiding the amplification of seismic waves.

If it is not convincing enough:

Recent scientific studies using very powerful and modern equipment found the ultimate evidence that the pyramids stones are synthetic. Believing in the artificial stone theory, or countering it, is simply no longer relevant. It has become a fact, a truth.

5- One scientist / expert has analyzed the stones and claims they are natural, so you are wrong!

The analysis methods used today by geologists are not relevant. These methods are used to CLASSIFY not to determine natural or artificial species. They cannot make a difference between a natural and a synthetic mineral. Indeed, the molecule of a mineral is by essence always the same, whether it is natural or synthetic, otherwise it would be another molecule, so another mineral. In addition, experts / scientists who oppose the theory of re-agglomeration have scarcely knowledge or understanding of the geopolymer chemistry. They will not know how to analyze this and will miss the evidence. Have the opponents ever analyzed a geopolymer and gain some understandings? Never! Ask them for their scientific papers on geopolymers, if they have ever published one. Take a close look at their studies: they assert that the stones bear the features of natural rocks, and these are their only claims. They imply that the geopolymer is inherently artificial and therefore that its synthetical nature would be immediately obvious, superbly ignoring the principles of geochemistry. Their ignorance of geopolymers deceives them. To our knowledge, no geologist has yet published a comparative analysis between a present-time geopolymer fossil shell limestone and an ancient pyramid stone. They criticize the system without having the slightest idea of what we are talking about. This leads to an unproductive debate with inconclusive results. Geopolymer is a hard science, not a speculative study. To show the geopolymerization and the artificial nature of the material, they need to work with more powerful methods. These tools are seldom used by them. Studies have been made with modern and powerful equipment, and all show that the stones are artificial. Opponents prefer to ignore them, it is out of their skill to argue against.

To find out more, here are our answers to the 3 geological studies most often cited by the opponents. Our claims are so straightforward that no scientific knowledge is required to understand them. It is time to put an end to this pseudo-science. Read: Deep Misleading Publications by Geologists

If it is not convincing enough:

According to recent scientific studies, believing in the artificial stone theory, or countering it, is simply no longer relevant. It has become a fact, a truth.

6- There are granite blocks that are carved but roughly trimmed. So, your theory is wrong.

We have never claimed granite was artificial (another hearsay). Indeed, granite is not carved (they did not have the right tools) but split (a very different skill). You will read below in the extended abstract under the “Religious context” why they used granite, because it represents the southern country. The granite was not carved in a quarry, but simply taken from individual boulders found in great quantities in the Aswan region. The boulders were split to fine dressed faces, leaving a typical rough undressed back. They represent less than 0.1% of the total blocks. Workers had 10 years to install them in the pyramid, and 10 years to carve a unique sarcophagus with whatever technique they have at their disposal. In short, we don’t care! We care about the 99.9% of limestone blocks. For Kheops, one block must be placed every 3 minutes.

If it is not convincing enough:

Recent scientific studies using very powerful and modern equipment found the ultimate evidence that the pyramids stones are synthetic. Believing in the artificial stone theory, or countering it, is simply no longer relevant. It has become a fact, a truth.

7- The analysis in favor of the artificial stone theory are invalid because they are not official.

Right. Egyptologists are historian, linguists, archeologists but none are material scientists! So, there will never be official analysis carried out by them, they will always rely on experts like us. By the way, are the opponents officials? Are there published rebuttals official? And the person you are talking with, who is against the re-agglomerated stone theory, is it an official person expressing an official opinion? Absolutely not, never, none of them can claim that. Their argument has no more value than yours. You are at the same level! And what about the numerous carving theories, are they official? Are they promoting another new unofficial carving theory? (see above)

If it is not convincing enough:

Recent scientific studies using very powerful and modern equipment found the ultimate evidence that the pyramids stones are synthetic. Believing in the artificial stone theory, or countering it, is simply no longer relevant. It has become a fact, a truth.

8- Another new study / investigation shows something strange in the pyramids…

None of the recent studies, using new tools and high-tech equipments are countering the artificial stone theory. It is often the opposite, it may be interpreted as a new evidence for re-agglomeration. Each time, they raise new questions and enigma that the carving theories cannot answer, fueling crazy speculations.

And, by the way:

Recent scientific studies using very powerful and modern equipment found the ultimate evidence that the pyramids stones are synthetic. Believing in the artificial stone theory, or countering it, is simply no longer relevant. It has become a fact, a truth.

9- Aliens and/or ancient advanced civilization built the pyramids.

These people are reading all the contradictory, unofficial, numerous carving theories, and because all of them raise more questions than answers, they imagine a radical solution: a super civilization must have done it. We consider this belief as an insult to the genius of mankind, as if Homo sapiens is a stupid creature and what we believe are human achievements are a fraud. The geopolymer chemistry used to build the pyramids is a very simple technology, much easier than you think. They have all ingredients at the vicinity. It is a natural evolution of a technology having its origin from mineral binders, ceramics, pigments, ores, and simple chemistries. It gives extraordinary results, yet with straightforward knowledge. It is much more complicated to make copper tools, or metallurgy in general, by selecting the right ore (there are many that look like the same), using the right process at the right time and temperature…

More pictures, drawings, details, information, videos are available at this page. Only a lengthy summary is published below.

Extended abstract of the theory with a simplify list of arguments

In his books, Why the Pharaohs built the Pyramids with Fake Stones (2009-2017), Professor Joseph Davidovits presented a theory on the pyramids’ construction: they were built by using re-agglomerated stone (a natural limestone treated like a concrete and then moulded), and not by using enormous blocks, carved and hoisted on ramps. Initially published in New York in 1988 under the title The pyramids: an enigma solved, this thesis has recently been released in several books with an important update of facts missing in the first American edition.

The theory is based on scientific analysis, archaeological elements and hieroglyphic texts as well as religious and historical aspects. Contrary to other theories that only seek a technical explanation for the Giza Plateau pyramids, and often looking only at Kheops itself and ignoring the others, his theory encompasses the building of all the pyramids of Egypt for 250 years, from the first of Zoser to those in crude bricks.

A- Theory

1. The formula and materials used:

The most important material is limestone. Analysis done by the German geochemist D.D. Klemm [1] showed that 97 to 100% of the blocks come from the soft and argillaceous limestone layer located in the Wadi, downwards the Giza Plateau. According to the Egyptologist Mr. Lehner [2], the Egyptians used a soft and crumbly limestone, unusable for hewn stones. The workmen did not choose the hard and dense limestone located near the pyramids, with rare exceptions for later restorations. The geologist L. Gauri [3] showed that this limestone is fragile, because it includes clay-like materials (in particular kaolinite clay) sensitive to water which explains the extreme softness of the Sphinx body, whereas its head, cut in the hard and dense geological layer, resisted 4000 years of erosion.

This soft argillaceous limestone, too fragile to be a hewn stone, is well adapted to agglomeration. Moreover, it naturally contains reactive geopolymeric ingredients, like kaolinitic clay, essential to manufacture the geological glue (a binder) and to ensure the geosynthesis.

It was not required to crush this stone, because it disaggregates easily with the Nile water during floods (the Wadi is filled with water at this time) to form a limestone mud. To this mud, they added reactive geological materials (mafkat, a hydrated alumina and copper silicate, overexploited at the time of Kheops in the Sinai mines) [4], Egyptian natron salt (sodium carbonate, massively present in Wadi Natrum), and lime coming from plants and wood ashes [5]. They carried this limestone mud in baskets, poured it, then packed it in moulds (made out of wood, stone, crude brick), directly on the building site. The method is identical to the pisé technique, still in use today.

This limestone, re-agglomerated by geochemical reaction, naturally hardens to form resistant blocks. The blocks thus consist of 90 to 95% of natural limestone aggregates with its fossil shells, and from 5 to 10% of geological glue (a cement known as “geopolymeric” binder) based on aluminosilicates.

2. Why do geologists see nothing?

This is due to the geological glue, which, though artificial, is seen by the geologists either as an impurity, and therefore useless to study, or as a natural binder. At best, the analysis tools and the working methods of geologists consider the glue as a perfectly natural “micritic binder”. Joseph Davidovits manufactured an artificial limestone containing 15% of synthetic binder, and submitted it to geologists who, on studying it, suspected nothing [6].

A geologist not informed of geopolymer chemistry will assert with good faith that the stones are natural.

3. The chemical formula:

The geosynthesis aims to react the kaolinite clay (naturally included in the Giza limestone) with caustic soda (see chemical formula 1). To manufacture this caustic soda, they use Egyptian natron (sodium carbonate) and lime (coming from plant ashes) (see chemical formula 2). Then, they get soda which will react with clay.

But the most interesting point is that this chemical reaction creates pure limestone as well as hydrosodalite (a mineral of the feldspathoids or zeolites family). [6]

Chemical reaction 1:
Si₂O₅,Al₂(OH)₄ + 2NaOH = > Na₂O.2SiO₂Al₂O₃.nH₂O
kaolinite clay + soda = > hydrosodalite

Chemical reaction 2:
Na₂CO₃ + Ca(OH)₂ = > 2NaOH + CaCO₃
Sodium carbonate (Egyptian natron) + lime = > soda + limestone

Summary of the re-agglomerated stone binder chemical formula:
clay + natron + lime = > feldspathoids + limestone (i.e. a natural stone)

The re-agglomerated stone binder is the result of a geosynthesis (a geopolymer), which creates two natural minerals: limestone and hydrated feldspar (feldspathoids). We understand why the geologists can easily be misled.

4. Scientific analysis:

Now that more and more scientists agree and support the theory, some have decided to carry on researches without my help and without requesting any approval from egyptologists, so in total independence from both parties.

The analysis methods used today by geologists are not relevant. They cannot make a difference between a natural and a synthetic mineral. Indeed, the molecule of a mineral is by essence always the same, whether it is natural or synthetic, otherwise it would be another molecule, so another mineral. To show the artificial nature of the material, they need to work with more powerful methods (analysis by synchrotron, transmission and electronic scan microscopy SEM TEM, Nuclear Magnetic Resonance, Paleomagnetism, Particle Induced Gamma-Ray Emission, Particle Induced X-Ray Emission, X-ray fluorescence, X-ray Diffraction). These tools are seldom used in this situation. Studies have been made, and all show that the pyramid stones are artificial. [7]

This last paleomagnetism study is simply the ultimate proof that the pyramids blocks are not natural. You may find various papers or opinions challenging the theory, but all prefer ignoring these independent analysis. Believing in the artificial stone theory, or countering it, is simply no longer relevant. It has become a fact, a truth that is still fought by some people for irrational purposes.

We can quote the following scientific papers:

• Paleomagnetic investigation of the Great Egyptian Pyramids, Igor Túnyi and Ibrahim A. El-hemaly, Europhysics News 2012, 43/6, 28-31.
• Were the casing stones of Senefru’s Bent Pyramid in Dahshour cast or carved? Multinuclear NMR evidence, Kenneth J. D. MacKenzie, M. E. Smith, A. Wong, J. V. Hanna, B. Barryand M. W. Barsoum, Mater. Lett., 2011, 65, 350.
• Microstructural Evidence of Reconstituted Limestone Blocks in the Great Pyramids of Egypt, Barsoum M.W., Ganguly A. and Hug G., J. Am. Ceram. Soc. 89[12], 3788-3796, 2006.
• The Enigma of the Construction of the Giza Pyramids Solved?, Scientific British Laboratory, Daresbury, SRS Synchrotron Radiation Source, 2004.
• PIXE, PIGE and NMR study of the masonry of the pyramid of Cheops at Giza, Guy Demortier, NUCLEAR INSTRUMENTS and METHODS in PHYSICS RESEARCH B, B 226, 98 – 109 (2004).
• X-Rays Analysis and X-Rays Diffraction of casing stones from the pyramids of Egypt, and the limestone of the associated quarries., Davidovits J., Science in Egyptology; A.R. David ed.; 1986; Proceedings of the “Science in Egyptology Symposia”; Manchester University Press, UK; pp.511-520.
• Differential thermal analysis (DTA) detection of intra-ceramic geopolymeric setting In archaeological ceramics and mortars., Davidovits J.; Courtois L., 21st Archaeometry Symposium; Brookhaven Nat. Lab., N.Y.; 1981; Abstracts P. 22.
• How Not to Analyze Pyramid Stone, Morris, M. JOURNAL OF GEOLOGICAL EDUCATION, VOL. 41, P. 364-369 (1993).
• Comment a-t-on construit les Pyramides: polémique chez les Égyptologues, HISTORIA Magazine, Paris, No 674, fév. 2003, dossier pp. 54-79 (2003).

B- The Archaeological Evidence

1. The hieroglyphic texts:

We know the Egypt of the Pharaohs quite well, thanks to its numerous steles, frescos and papyrus describing all kinds of religious, scientific, technical knowledge, the craft industry, agriculture, medicine, astronomy, and so on. However, there is not a single hieroglyphic document revealing the pyramids’ construction with carved stones, ramps, and wooden sledges. On the contrary, we find many texts showing that the ancient Egyptians had the knowledge of man-made stones:

The Famine Stele is engraved on a rock at Sehel island, close to Elephantine. It stages the god Khnum, Pharaoh Zoser and his architect Imhotep, builder of the first pyramid at Saqqarah. This inscription contains 650 hieroglyphs depicting either rocks and minerals, or their transformation processes. In column 12, we read: “With these products (mineral) they built (…) the royal tomb (the pyramid)“. In columns 18 to 20, the god Khnum gives to Zoser a list of minerals needed in the construction of these sacred monuments. This list does not mention the traditional hard and compact construction stones like limestone (ainr-hedj), monumental sandstone (ainr-rwdt) or Aswan granite (mat). By studying this text, we notice that we cannot build a pyramid or a temple with simple minerals, except if they are used to manufacture the binder of a re-agglomerated stone. [8]

The Irtysen stele (C14) at the Louvre Museum is an autobiography of the sculptor Irtysen under one of the Mentouhotep Pharaohs, eleventh dynasty (2000 B.C.). It explains the method of manufacturing synthetic stone statues (with “cast stone”). [9]

The Ti fresco, fifth dynasty (2450 front. J.-C.), illustrates the sculptors work on a wooden statue, the manufacturing of a stone statue and mixtures in vases. This fresco perfectly shows the difference between carving a statue (here in wood with hieroglyphic signs depicting the operation of carving), the fashioning of a statue (made out of synthetic stone with hieroglyphic signs representing the action “to synthesize”, “man-made”), and mixing caustic chemicals in ceramic vases to work on this statue. [10]

2. The invention of re-agglomerated stone: growth and decline of a technology

Before the first pyramid built out of stone, the ancient Egyptians constructed very imposing crude brick monuments. We find large funerary temple enclosures of the second dynasty, like the Khasekhemwy one (2,730 B.C.). Its massive wall is of crude clay bricks, therefore in a moulded material. It is generally agreed, since these bricks were worked in moulds, that their dimension must be uniform. However, this is wrong. Despite having been manufactured in moulds, the clay bricks are of approximately 5 different sizes, implying the use of several patterns. We find these differences in proportions in all pyramids. This heterogeneity gives the monuments the ability to resist earthquakes by avoiding the amplification of seismic waves.

20 years later, Zoser ordered Imhotep to build him a stone monument for eternity. The scribe Imhotep is the inventor of re-agglomerated stone (2,650 B.C.) and the architect of the first pyramid of Egypt. Instead of using crude bricks, he simply replaced the clay with a re-agglomerated limestone and kept the same method of moulding bricks. This is why the first pyramid is made in small bricks, which become bigger in dimension as the invention is better mastered. The bricks are manufactured where the stones are extracted, in the Wadi (at the east of the complex [11]) at the Nile flooding period, then carried and placed on the pyramid under construction.

Its invention, inherited from pisé and crude brick, improves with time during the pyramids’ construction at the third and fourth dynasties. Starting from the small limestone bricks at Saqqarah, the stone dimensions increase gradually. For the Meidoum and Bent pyramids, the blocks are produced in the vicinity and are moved up to the pyramid. There is always a Wadi nearby to easily disaggregate limestone with water and to prepare the mixture at the Nile flooding time.

From Sneferu’s red pyramid in Dashur, the blocks are manufactured on the spot, because the dimensions are now too large for them to be transported.

In Giza, some stones (in particular those at the Khefren temple) weigh more than 30 tons. How would they have simply carved them with soft copper tools, without wheels or pulleys?

According to Guy Demortier [12], re-agglomerating stones on the spot greatly simplifies the logistic problems. Instead of 25,000 to 100,000 workmen necessary for carving [13], he deduces that the site occupancy never exceeded 2,300 people, which confirms what the Egyptologist Mr. Lehner discovered with his excavations of the workmen’s village at Giza.

The decline of the agglomerated stone technology appears with the pyramid of Mykerinos, which represents only 7% in volume of Kheops. Why is this pyramid suddenly so small? This decline would have been caused by a sudden reduction in reactive mineral resources, like the exhaustion of the principal Sinai mines at the end of the fourth dynasty. Expeditions of B. Rothenberg [4] showed that they had extracted enormous quantities of turquoises and chrysocollas (called mafkat in Egyptian), quantities so large as to rule out their use in jewellery and decoration, as confirmed by the Egyptologist Sydney Aufrère [14].

The decline would also result from an ecological and agricultural disaster radically limiting the production of lime coming from plant ashes burned for this purpose. If we burn more than what we can produce or renew, a famine or an ecological disaster can occur. Analyzed by D.D. Klemm [15], lime, present in mortars of the third and fourth dynasties, disappears in mortars of the fifth and sixth dynasties. Indeed, the succeeding pyramids, and in particular that of Userkaf, first king of the fifth dynasty, is ridiculously small compared to Mykerinos. In the beginning, they were covered by a limestone coating which hid the bulk of natural blocks, badly worked out. This pyramid is only an uneven stone assembly covering a funerary room made, this time, out of re-agglomerated stone and protected by enormous beams of several dozen tons. Only the core of this pyramid was carefully manufactured, the remainder being botched, because the reactive materials were rare. Thus, we are in the presence of a very different system, which cannot be explained by carving stone. If the pyramids of Giza had been hewn, how can such a drop in architectural quality be explained, while stone is an abundant material? Carving would have resulted in a construction quality equivalent to those of Giza, even with pyramids more reasonable in height, but this is not the case.

With respect to a resource impoverishment, starting from the twelfth dynasty (1,990-1,780 B.C.), Pharaoh Amenemhat I and his successors built crude brick pyramids. But here also, only the funerary room is built, with great care, out of re-agglomerated stone. However, the Egyptians did not choose to carve stone for the body of the pyramids, preferring crude bricks, even though they had harder and more efficient bronze tools had they wished to use them.

We note, then, that the technology of re-agglomerated stone, after a formidable rise, a perfect mastery of the process, an intense exploitation of its resources, went on to  an extremely rapid architectural decline. A mining exhaustion of the chemical reagent resources, and an ecological and agricultural disaster explain this decline. [16] [17]

3. Religious context:

Why did they maintain this need to build out of agglomerated stone or to preserve the agglomeration system, while they could carve stone?

For ancient Egyptians, stone had a sacred quality, used only for religious purposes, that prohibited its use for secular buildings (built rather out of crude bricks, clay and wood, never out of stone). It is only under the Ptolemys, 2,000 years after the pyramids, that stone became a trivial building material. The reasons for this distinction come from religion.

Egyptian civilization lasted more than 3,000 years and, contrary to what the general public thinks, it was not homogeneous. Thus, there are 2 geneses explaining the creation of the World; two distinct gods claim the creation of the World and man: Khnum and Amon.

The god Khnum was worshipped during the Old and Middle Kingdoms (3,000 to 1,800 B.C.). He is depicted as a man with a ram’s head and horizontal horns. He personalizes the nutritious Nile, and at Elephantine, Thebes, Heracleopolis, Memphis, he is the god of creation. In the act of creation, he “kneads” humanity on his potter’s wheel with the Nile silt and other minerals (mafkat, natron) as in the Biblical and Koranic genesis. This does not give an unspecified clay, but a stone called “ka”, i.e. the soul that is not spirit, but eternal stone. Khnum and all the divine incarnations of Râ appear by the act of manufacturing stone. His hieroglyphic sign is a hard stone vase like those of the Nagadean era (3,500 to 3,000 B.C.). Thus, under the Old Kingdom, the purpose of the agglomeration act was to reproduce the divine intervention at the time of the creation of the World and the human soul.

For the two main Pharaohs of the Old Kingdom, Zoser and Kheops, the relationship with Khnum is proven by archaeological discoveries (cf. the Famine Stele). Also, the true name of Kheops is Khnum-Khufu (may the god Khnum protect Kheops). Would Kheops have attached his name to an inferior god? No, Khnum is a major god. It is simply the perception of the Egyptian Pantheon which is not correct.

Amon is the second god of creation. In the beginning, he was only an average god. He became a dynastic god in the twelfth dynasty (1,800 B.C.), but he was not yet the god of creation, this role still being the privilege of Khnum. Then, he became the “king of the gods” and the priests gave him the ability to create the world. In the genesis myth, Amon is identified as a sacred mountain and he “carves” each human being in a part of himself, i.e. in this sacred mountain. Amon and all the divine incarnations of Amon-Râ appear by the act of carving stone, and are at the origin of the New Kingdom monuments, like those of Ramses II, 1,300 years after the pyramids.

Thus, we understand why the tombs were no longer under pyramids, symbols of agglomeration, but under a sacred mountain, the Valley of the Kings, symbol of Amon. In the same way, the temples are built out of stone hewn with great care and the obelisks are called “Amon’s fingers”. During the Old Kingdom, where the name of Khnum (“the one who binds”) is in the complete name of Kheops (Khnum-Khufu), the name of Amon (“the one who is hidden”) is found in the New Kingdom Pharaohs’ names like Amenhotep.

Arguments against the carving theory

Here are arguments presented by the partisans of carving to show that this technique was in use at the pyramids’ time. However, these evidence are anachronous; they date from the Middle to the New Kingdom, in times when the stone was hewn, and not from the Old Kingdom, the time of the pyramids.

The extraction of blocks would have been possible by means of wooden dowels that, once in place, were wetted to cleave the stone. However, D.D. Klemm shows that the Romans only used this primitive technique very late on. Each period left distinct patterns of cut traces in quarries, thus making it possible to date them, except at the time of the pyramids, when no trace remains. [18]

The bas-relief of Djehutihotep illustrates the transport of a colossal statue on a sledge [19]. In the same way, R. Stadelman discovered that Amenemhat II workmen had stolen stones on sledges from the Sneferu pyramid, used as a vulgar quarry. These two events took place under the twelfth dynasty (1,800 B.C.), that is 700 years after the construction of the pyramids.

The Tura stele depicts a stone block dragged on a sledge by oxen [20]. It does not constitute a proof because once again, it goes back to approximately 1,000 years after the construction of the pyramids.

The Rekhmire fresco presents the work of masons setting up blocks with bronze tools. But these new tools were unknown to pyramid builders 1,300 years earlier.

Any ramps would have been made out of crude clay bricks, several kilometres in length (in straight or spiral lines, with the attendant problem of turning corners), representing a considerable amount of material. Each team would have sprinkled the ground with water to ease the motion of the sledge. But the action of water would have transformed the ramp into a soapy and very slippery path. After several teams had passed by, it would have been transformed into mud where sledges and hauler would be stuck!

There is no official theory of carving, hauling blocks on sledges and ramps. There are approximately twenty or so that propose various solutions. These theories are not based on hieroglyphic texts, do not match the technology found on archaeological sites, and do not take into account the historical and religious environment. These theories are essentially focused on the pyramid of Kheops, the most remarkable one, but not on the pyramids that precede or follow it, and even less on those made out of crude brick.

Notes and references

[1] Klemm, Steine und Steinbrüche in Alten Ägypten, Springer Verlag Berlin Heidelberg, 1993.
[2] M. Lehner, The Development of the Giza Necropolis: The Khufu project, Mitteilungun des Deutschen Institutes, Abteilung Kairo, 41, p. 149, 1985.
[3] L. Gauri, Geological study of the Sphinx, Newsletter American Research Center in Egypt, No 127, pp. 24-43, 1984.
[4] B. Rothenberg, Sinai exploration 1967-1972, Bulletin, Museum Haaretz Tel Aviv, 1972, p. 35
[5] J. Davidovits, Ils ont bâti les pyramides, éd. J-C Godefroy, Paris, 2002, pp. 161-162, 307-311
[6] J. Davidovits, La nouvelle histoire des pyramides, éd. J-C Godefroy, Paris, 2004, pp. 57-58 et 72
[7] See ref. [5] and [6] for comprehensive bibliographics notes and debates with geologists.
[8] Pyramid Man-Made Stone, Myths or Facts, III. The Famine Stela Provides the Hieroglyphic Names of Chemicals and Minerals Involved in the Construction , Davidovits J., 5th Int. Congress of Egyptology, Cairo, Egypt, 1988; Egyptian Antiquities Organization; EGY; 1988; pp. 57-58 in Résumés des Communications. See also ref. [5] and [6].
[9] J. Davidovits, Ils ont bâti les pyramides, éd. J-C Godefroy, Paris, 2002, pp. 229-236
[10] J. Davidovits, La nouvelle histoire des pyramides, éd. J-C Godefroy, Paris, 2004, pp. 145-150
[11] M. Lehner, The Complete Pyramids, Thames and Hudson, 1997, p. 83
[12] G. Demortier, La construction de la pyramide de Khéops, Revue des questions scientifiques, Bruxelles, 2004, Tome 175, p. 341-382
[13] M. Lehner, The Complete Pyramids, Thames and Hudson, 1997, p. 224
[14] Sydney Aufrère, L’univers minéral dans la pensée égyptienne, IFAO, Le Caire, 1991, Volume 2, p. 494
[15] D.D. Klemm and R. Klemm, Mortar evolution in the old kingdom of Egypt, Archaeometry ’90, Birkhaüser Verlag, Basel, Suisse, 1990, pp. 445-454
[16] J. Davidovits, Ils ont bâti les pyramides, éd. J-C Godefroy, Paris, 2002, pp. 297-328
[17] J. Davidovits, La nouvelle histoire des pyramides, éd. J-C Godefroy, Paris, 2004, pp. 207-228
[18] Klemm, The archaeological map of Gebel el Silsila, 2nd Int. Congress of Egyptologists, Grenoble, 1979, Session 05.
[19] J. P. Adam, l’Archéologie devant l’imposture, éd. Robert Laffont, Paris, 1975, p. 158
[20] Vyze-Perring, The Pyramids of Gizeh, Vol. III, p. 99

There are hundreds of companies manufacturing and selling geopolymer products worldwide.

And a lot more are not claiming they are using the geopolymer chemistry to keep their know-how secret. So, search the web and find patents. You will get a comprenhsive list of commercial applications.

No-one can register this word alone as a trademark in any country, it will not be valid. However, it is possible to associate the word geopolymer with other words to form a trademark. More information here.

But, please, keep in mind that the word geopolymer has a precise meaning, a clear definition . Using it means you agree with this science and definition.

However, there is always some amount of metakaolin that is consumed with reference to XRD, IR and MAS-NMR spectral.

X-ray diffraction of geopolymers of the Na-PSS, K-PSS, (Na,K)-PSS types, are rather boring because they are amorphous by XRD. We get an amorphous diagram. Details are given in Prof. Davidovits’ book Geopolymer Chemistry & Applications, Chapter 4.

What you see in XRD are not remains of the raw-material (in this case the so-called metakaolin), but of the crystalline elements, which are always found in it, for example: muscovite, titanium oxide, quartz, etc. These elements do not take part in the geopolymerization.

As for 27Al NMR, the spectrum does not contain any Al(V) and Al(VI) sites, exclusively Al(IV). If you find remains of the so-called metakaolin, i.e. Al(V-VI), this means that your experimental conditions are not appropriate.

Prof. Dr. Joseph Davidovits.

In your email, you said that it should be noted to avoid using general term such as METAKAOLIN. In fact, many naturally occurring and man-made Si-Al materials with low calcium have been used to synthesis various types of geopolymers in recent 3 years. However, the results showed that the mechanical, durability properties of geopolymer synthesized by other raw materials through room temperature curing are not as good as those by metakaolin. Thus I think metakaolin is a very key or necessary constituent raw material for preparing high performance geopolymers in room temperature. In addition, there are immense amounts of kaolin, especially medium or lower grade kaolin in china, which are not still applied.

Why do we have to avoid using the wording METAKAOLIN??

The word metakaolin means: another type of kaolin. It does not provide any information on the reactivity, the physico-structure, and its ability to geopolymerisation. The word metakaolin, in the industry, refers to kaolin OR Kaolinitic clays dehydroxylated, that is to say thermally treated at a temperature above 450°C. Industrial metakaolin are thermally treated either at:
500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000°C.
These products are used as fillers for organic plastics, rubber, paper, etc. or as pozzolanic additives in Portland cement.
Above 1000°C, the products are called: chamotte, and are used in the ceramic industry.

The calcined kaolinite we need for geopolymerisation is an alumino-silicate oxide with a very specific 27Al NMR spectrum, essentially with very well resonances at 55 and 20-25 ppm, assigned to Al(IV) and Al(V) coordination with O.

In order to emphasize the fact that we are selecting a material containing the mineral KAOLINITE (not the kaolin), i.e. clays which contains this poly-silico-aluminate, such as: kaolin, kaolinitic clays, dickite clays, nacritic clays, and perhaps also halloysite clays, I am using the term MK-750 [MetaKaolin-750°C] (or KANDOXI, an acronym for KAaolinite-Nacrite-Dickite-OXIde). This oxide is the one, which has the NMR spectrum with Al(IV-V).

In my book Geopolymer Chemistry & Applications I am using the wording metakaolin MK-750, or MK-750 alone..

Prof. Dr. Joseph Davidovits

Geopolymer combines the merits of cement and ceramics, we can make materials with the properties of ceramics by a process like cement. Water reducing agents are popular in cement industry.
The question is what will happen in geopolymer?

Experiences carried out with geopolymer cements show good results with regular water reducing agents used for Portland Cement. The optimal content should not be greater than 1 per cent by weight of the cement. Higher content induces lower mechanical properties.

Prof. Joseph Davidovits

I’m a sixth form student studying chemistry. I am interested in doing a project at college similar to the one you have done on recreating the stone used in the pyramids and building a small replica to show the method that might have been used.
I’ve looked over the information on this site and others but most of it is too technical for my level of chemistry. The closest article to the kind of thing i am after is “Making Cements with Plant Extracts” Is it possible to give a more “simpler” explanation of how i can accomplish this project? i.e. a step by step guide on how to make the limestone cements with various plants or other chemicals (silicates).

A fellow (not J. Davidovits) answered:

Check out this story of Fawcett’s observations during one of his expeditions, at www.spirasolaris.ca/waterstone.html. In my own research, the three main acids involved are; acetic (in vinegar), citric (lemons, etc) and oxalic. Oxalic acid is found in the oxalis family (botany) and wood sorrel is one common northern hemisphere variety.
I haven’t performed any experiments yet, however, my hypothesis is to crush or chop fresh oxalis (you will need to check the variety as acid content varies from each type) whilst completely submerged in fresh squeezed (not the commercial type in a bottle!) lemon juice. The citric acid apparently acts as a catalyst to increase the amount of oxalic acid within the plants’ cells. After an as yet undetermined period of time, filter out the plant solid and add vinegar (acts as a preservative). Test on your chosen stone, take notes. Try other batches with varying quantities of each ingredient, see what you come up with!
If you wish to try this, please let me know how it goes. I don’t have any lab (or even a shed!) to work in, so can’t really find out any more than I already have. Good luck!

You answered my question about kaolinite calcination. You said me to see your patent 5,288,321. I read it and I understood that you obtained a metakaolinite, calcined between 700°C and 800°C, with aluminium coordination number of IV, V and VI. In this temperature I would obtain less aluminium VI than IV or V. In your others patents about Geopolymer you always emphasized that its synthesis must start with Al(IV) and/or Al(V), but never with Al(VI). My questions are: 1) Can I have some Al(VI) in the metakaolin used in the geopolymer synthesis or not? 2) Do you think that there is some calcining conditions that allows all Al(VI) be converted in Al(IV) and/or Al(V)?
Valeria Figueiredo Felisbino Barbosa, Instituto Militar de Engenharia, DE/4, Rio de Janeiro, Brazil

When, in 1978-1979, I made the first (Na,K)-PSS GEOPOLYMITE binder, scientific knowledge was based on X-Rays investigation methods.

It was generally accepted that the coordination of Al in calcined kaolinite was Al(IV). See for example the paper by A.J. Leonard, “Structural Analysis of the Transition Phases in the Kaolinite-Mullite Reaction Sequence”, J. Am. Ceram. Soc., 60 37-43 (1977). The use of MAS-NMR spectroscopy had not been developed, so far. The first paper on that topic was published in 1985 by K.J.D. MacKenzie et al., “Outstanding Problems in the Kaolinite-Mullite Reaction Sequence Investigated by 29Si and 27 Al Solid-State Nuclear Magnetic Resonance: I, Metakaolinite”, J. Am. Ceram. Soc., 68 293-97 (1985). Their study showed that 800°C calcined kaolinite contained about 10% of the total Al sites in Al(VI) coordination. This was a big surprise. In 1988, J. Sanz et al. published a paper that introduced the new discovered and strongly debated Al(V) coordination, “Aluminum-27 and Silicon-29 Magic-Angle Spinning Nuclear Magnetic Resonance Study of the Kaolinite-Mullite Transformation”, J. Am. Ceram. Soc., 71 C-418-C-420 (1988). This later paper is important for your understanding of the calcination parameter.

I always introduced in my patent description the newest knowledge in terms of Al coordination. It is therefore not wise to compare claims and descriptions dating back to 1979-1980 with those filed later in the 1990’s.

You’ll find recent detailed explanation in my newest book (2008) Geopolymer Chemistry & Applications, Chapter 8.

Prof. Joseph Davidovits

1) single crystals, page 1637: this means that the crystals obtained in diluted medium, which is always the case by the fabrication of zeolites, these crystals can been seen by naked eye. They are big. The paragraph you are referring to is dealing with “Crystalline Poly(sialate) (- Si-O-Al -)”. Crystalline geopolymers require hydrothermal conditions as stated in the paragraph “Amorphous Poly(sialate-siloxo)”, page 1638.

2) Fig. 4: X-ray diffractogram: short time reaction yields a certain amount of Zeolite A. Longer time reaction prevents the formation of Zeolite A yielding only Na-PS, hydrosodalite. This can be followed by the measure of the coefficient of absorption. Zeolite A has an open structure and exhibits a very high coefficient of absorption. On the opposite, Na-PS is densely packed with a very low coefficient of absorption, 10 time less than Zeolite A. The X-ray diffraction patterns are different. The 60 minutes X-ray pattern belongs to Na-PS, not to a weak Zeolite A.

3) Since 1979, when I was able to produce the first liquid geopolymeric binder (Na,K)-PSS type, the generic term geopolymer is dedicated to liquid binders or cements like those displayed in Table 6, page 1646. I do not use this generic term to designate the crystalline material that is obtained in the ceramic bodies. The technology associated with ceramic bodies is called L.T.G.S., which means Low Temperature Geopolymeric Setting, see page 1649. When discussing with Johan van Jaarsveld, for both of us, geopolymer meant a liquid binder or a cement. In that case, geopolymers are amorphous.

My name is Prof. Mario Collepardi and I am a professor of “Materials Science and Technology” at the Politecnico of Milan, Italy. Yesterday I have seen your interview by Mr. Giacobbo at the “Stargate” program on “La 7” Italian TV channel. I am very interested to your theory about the building technique used by Egyptians for the Pyramids, even because my research work is in the area of cement chemistry and concrete technology (www.encosrl.it ). I am sure that this technique, according to your theory, can explain how the Egyptians could erect the Pyramids without using sophisticated techniques of cutting, transporting and rising heavy blocks of natural stones, which were not available at that time.
I have three questions:
A) As far as I know, the Egyptians at the time of the Pyramids were able to produce gypsum (in form of calcium sulphate hemy-hydrate) as binder, but they were not still able to manufacture lime due to the higher burning temperature (900 °C instead of 150°C) with respect to that required for the gypsum manufacturing process. Am I correct? If so, how can you justify that the Egyptians were able to use lime as one of the ingredients for the concrete mixture used in the Pyramids? Were the “engineers” of the Pyramids at a more advanced progress with respect to their colleagues in the other areas of Egypt?
B) I understand, from your interview, that the limestone aggregate available in the area of the Pyramids was relatively rich in the clay content (a sort of a marl rock), so that the concrete mixture in the fresh state was cohesive and relatively easy to compact up to a dense and hard cementitious material. If so, the lime manufactured by treating at high temperature the limestone available in that area was really a sort of mixture of calcium oxide and metakaolin (belonging to the family of pozzolanic materials) and this could explain the hydraulic behaviour of that Egyptian concrete even in the absence of carbonation. In other words, not necessarily the Egyptians had to use natron (sodium carbonate) to transform the lime into calcite. Isn’t it?
C) Have you found natron in the area of the Pyramids? If so, how could the Egyptians, at that time recognize and individuate this mineral without any chemical background?

A) Lime versus gypsum: you are not correct. This is part of the granted ideas introduced by Egyptologist A. Lucas in 1924. Yet, calcining limestone into lime requires temperatures far lower than the temperatures needed for smelting copper. A. Lucas postulated that lime was not calcined in Ancient Egypt until the Ptolomaic time, i.e. 2000 years after the pyramids were built because of the scarcity of wood as fuel. But the Egyptians had several trees at their disposal: the acacia, the carob, two species of palm, etc. The truth is that it was difficult to detect lime in the mortars, for several reasons. Yet, owing to new sophisticated techniques, modern science has shown that lime has been found in mortars from the III, IV and V. dynasties, not in the VI and later. (Analysis by D.D. Klemm, 1990).

B) But lime CaO is not produced by calcining limestone. It is the result of the making of bread. The ashes of Palm wood and reeds they used for bread cooking contain a very high amount of CaO. This explains why we do not find kilns for lime, but very important bakeries (for bread) with great quantities of ashes. In my new book , recently published in Paris, titled: Ils ont bati les Pyramides (They have built the pyramids), I have dedicated several pages to this issue. They had sufficient ashes from bread cooking to make all the pyramids they wanted. The only problem was to collect them and to transport them to the site.

C) They were intelligent and smart; it is very easy for a non chemist to recognize between NaCl (common salt) and Na2CO3 (natron, sodium carbonate), just by the taste.

Prof. Dr. Joseph Davidovits

After drying has occurred, the volume occupied by the water molecules is empty. This results in a matrix full of micro-voids. I guess you understand that strength is directly correlated with the voids content. Yet this property is also very interesting in terms of freeze-thaw properties and thermal shock. Microvoids and microchannels are very useful to prevent any damage caused by absorbed freezing water.

However, to manufacture fiber reinforced composites, the impregnation of fibers requires very low viscosity. We achieve this very low viscosity by decreasing the ration 1:12 to 1:15 or 1:20.

But because we still want to achieve high mechanical strength, the impregnated fabric is vacuumed at ambient temperature, to evaporate the excess of water.

The US patent you are referring to is dealing with the method of production of M-PSDS geopolymer. If you go back to the earlier patents which dealt with the processing of M-PS or M-PSS geopolymer, you will learn that geopolymerisation occurs even with concentrations of solids that are lower than 60%.

Prof. Joseph Davidovits

These steps are disclosed in French in the published International patent application WO 89/02766, titled “Method for stabilization, solidifying and storing waste materials” published with modified claims and declaration, dated 05.05.1989. This was a second publication. Initial publication of WO 89/02766 dated 06.04.1989 did not contain this information.

Prof. Joseph Davidovits

I recently read your book regarding the construction of the pyramids and was impressed with the overall coherence of the theory. Hopefully, in the future, popular opinion will swing in your favor so that you might be allowed to take pyramid samples of your own. This theory is strangely prone to ridicule, yet resistant to attack.
Upon finishing the book, I was left with the impression that the case for the artificiality of the limestone pyramid blocks was stronger than the case for the artificial hard stones. Is the recipe for egyptain hard stone known, and can it be replicated? Do the physical properties differ from natural stone? How can one prove that a hard stone object is not carved from a natural block, but instead made from solidified man made material? I use the generic term hard stone as I am assuming the manufacture of artificial basalt, diorite, and granite involve the same process with different agglomerate.
Is it possible for the Egyptians to have poured molten stone into molds? I understand that molten basalt will produce diorite when cooled slowly. Molten diorite apparently will produce granite when cooled slowly. Could the addition of any substance (such as water) to the rock lower the melting temperature to a range the Egyptians could produce?

By answering to this message I would like to take the opportunity to state the following:
I do not want to be involved in any controversy dealing with artefacts made in Egyptian granite. My work and my revised book concentrate on the materials that constitute the bulk of the pyramids: limestone, sandstone, mud, additionally quartzite. I can replicate the hardening of these materials in my lab and I am only dealing with technologies that I can master. With respect to granite, I have started a research program dealing with EUROPEAN granite artefacts. The results are promising and I hope they will provide new clues as far as the EGYPTIAN granite is concerned. However, as long as I am not ready, I shall decline any discussion dealing with this topic.

As for your suggestion on smelting/cooling hard stone, we know of the making of artificial basalt in Mesopotamia (see the paper published in magazine Science: From Shifting Silt to Solid Stone, The Manufacture of Synthetic Basalt in Ancient Mesopotamia, by E.C. Stone and al., Science, Vol. 280, 26 June 1998, page 2091). We do not know so far if this is an unicum or an accident.

What I am trying to achieve in my lab is to get hard stone features WITHOUT SMELTING AND SOLIDIFYING stone mixtures. All mineralogical analysis performed on Egyptian hard stone artefacts (stone vases) dating from the Old Kingdom demonstrate that the hard stone is not a recently (young) recrystallized, slowly solidified matrix. The hard stones are in their great majority NEVER SOUND but strongly affected by SAUSSURITIZATION. This strange term, saussuritization, is used by geologists and petrographers when describing the alteration of hard stone constituent FELDSPAR to albite, epidote, calcite, sericite and/or zeolite.
In other word this strange geological term suggests geopolymerization, not smelting and slowly cooling. We always get this saussuritization mechanism when, in my lab, we solidify hard stone replicates obtained by the agglomeration of feldspar aggregates and modern geopolymer binder.

Joseph Davidovits

What is the mechanistic implications of the higher concentration of precursors in the case of geopolymer formation? In other words how does a higher precursor concentration affect the normal mechanism of zeolite formation (nucleation and crystal growth) in order to prevent crystal growth and create a geopolymer and not just an amorphous zeolite? My first guess was that because of the high concentration the monomeric species could not orientate themselves in a ordered crystalline framework, but I am still unclear about what does exactly happen when geopolymers form and how this can be explained in terms of molecular kinetics?
In terms of geo-chemistry, how would you distinguish between a crystalline product and a polymer made up of the same building blocks (i.e. Si and Al tetrahedrons) if you have to graphically represent their structural models? Will both not have the same repeating structural unit, depending on along which axis one looks?

Excerpt from Davidovits US Patent 5,342,595, col. 7, lines 11-31:
In the geopolymeric resin, the molar ratio K2O:Al2O3 is generally comprised between or equal to:
K2O:Al2O3 1:1 and 1.6:1

When the molar ratio K2O:Al2O3 = 1:1, the poly(sialate-disiloxo) (K)- PSDS Kn(- Si-O-Al-O-Si-O-Si-O -)n consists of SiO4 and AlO4 from type Q4, as determined by MAS-NMR
spectroscopy. The geopolymer structure is entirely tridimensional.

When the molar ratio K2O:Al2O3 is in the order of 1.3:1 or higher, the obtained geopolymer is less reticulated and contains SiO4 from type Q3 only. It is assumed that the film-forming properties
of the geopolymeric resin are due to this geopolymer type.

When the molar ratio K2O:Al2O3 is too high, this can lead to the production of Kn(- Si-O-Al-O-Si-O-Si-O -)n geopolymers with a linear structure where SiO4 is of type Q2; with aging, these linear
geopolymers can depolymerise and migrate throughout the matrix and occasionally induce surface defects on the manufactured ceramic items.

Prof. Joseph Davidovits

I have been following your work now for a couple of years and are mainly concerned with the toxic waste field and the potential application of Geopolymeric binders towards a toxic waste solution. I will also be writing up a Ph.D on this subject within the next year. As I did not have a lot of contact with other people in this field, there are various fundamentals about geopolymer chemistry that is still only vaguely explained as far as I am concerned. In many instances it took a lot of reading in the fields of geology, chemistry (silica) and zeolite syntheses to be able to comprehend and quantitatively describe precisely what is meant by the term geopolymerization in relation to the exact starting materials that one uses.
I have also read almost everything that you have written (including patents).
A fair amount of experimental work has also been done and will be published from now on. There are, however, certain aspects that I would like to discuss in order to better understand the fundamental side of geopolymerization as well as certain terminology that is not entirely clear to me.
What I meant is that you would not have heard or seen anything that we have done because we have not published up to now, it is only now that we feel confident enough to maybe publish something, although there are many things that we still don’t understand. A couple of people in Spain (Palomo et. al.) have published some material where they tried to quantified the microstructure of geopolymers, they also quoted you extensively. They proved that the order of addition of components influence strength in a big way. Again there is no explanation given why this is so?

The fact that the order of addition of components does influence strength is exemplified in my early patents (1979-1980, US 4,349,386 col. 4, lines 29-50).

The fundamentals of geopolymerization are described in my recent book (200) Geopolymer Chemistry & Applications, Chapters 2, 5, 6, 7, 8, 9, 10, 11, 12.

Prof. Joseph Davidovits

In your book,”The Pyramids”, you discuss possible casting methods for the casing stones of the Great Pyramid and Red Pyramid. You mention that there were inscriptions on the bottoms of these blocks, indicating they were cast upside down, then turned over. I am not Egyptologist, so please excuse my ignorance, but what did these inscriptions say, and what was the purpose of even having them on there?
Also, I recently obtained copies of the articles printed by yourselves and those of Cambell, Folk, et, al.. hoping to better understand the science of geopolymers. I think I have more questions than ever before now! Your opponents do make some interesting counterpoints to the cast-in-place theory, but they also fail to address other key points in your book:
What do they have to say about the quartzite burial chamber of Amenemhet III?
Or the famine stele?
What is there counter to your theory about the Grand Gallery in the Great Pyramid?
What do they make of the mafkat mining?
In the decade since your book was published, has anyone more eloquently tied together so many aspects of Egyptian history and technology?
Has anyone countered your interpretation of Pliny’s description of “murrhine vases”?
Are your opponents simply exploiting what little “cracks in your armor” and simply ignoring those parts of your theory that they cannot reasonably dispute?
Has anyone taken up your challenge concerning the famine stele and any other hieroglyphic texts that support your theory?

All the answers are either “they ignore it” or “they don’t disagree with my interpretations”.