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.

They prove the transfer of knowledge involving the man-made geopolymer stones found in the monuments of Tiwanaku/Pumapunku, located in the Altiplano, Bolivia, South America, to the manufacture of the artificial statues of Easter Island.

They demonstrate the relationship between South-America and Easter Island.

49 min, 148 MB. Click on the icon on the right to watch it fullscreen.

Content:

1. Brief history of the research undertaken since 1981. (1:36)
2. Summary of the results provided by our research at Tiwanaku/Pumapunku (Bolivia, South America) since 2017. (8:38)
3. What is the connexion with Easter Island? From whom came the knowledge?
 When? How did it happen? (21:53)
4. Scientific analysis! (34:32)

In this talk, you will learn for the first time:
Why do the statues of Easter Island exist?
Why do they have this unique shape?
Who invented them and why only on Easter Island?
Why some of them are different?
Why does it scream they come from South America?
Everything is based on scientific analysis and multidisciplinary studies that nobody connected before.
The genius of mankind…

This study is also available in the GEOPOLYMER LIBRARY for free download. Go to #K-eng. Tiahuanaco geopolymer artificial stones

Contents:

• Extended abstract
• Introduction
• Part 1. Pumapunku red sandstone megaliths
  • 1.1 Geological provenience of the megalithic sandstone blocks
  • 1.2 Scientific investigations: thin sections, optical microscope. X-rays diffraction, SEM / EDS, scanning electron microscope.
  • 1.3 Discussion.
• Part 2. Pumapunku gray andesite volcanic structures
  • 2.1 Extravagant and puzzling structures.
  • 2.2 Scientific investigation: thin sections, optical microscope, SEM/EDS, scanning electron microscope.
  • 2.3 Discussion: which chemistry ?
• 3. Conclusion

The video of the Geopolymer Camp 2018 conference presenting all the results in detail.

“The Megaliths at Tiwanaku / Pumapunku are artificial geopolymers.”

61 min, 272 MB. Click on the CC icon to display subtitles in english, français, espanol. Click on the icon on the right to watch it fullscreen. Available on Youtube !

“Los Megalitos de Tiwanaku / Pumapunku son Geopolímeros Artificiales”

61 min, 272 MB. Click on the CC icon to display subtitles in english, français, espanol. Click on the icon on the right to watch it fullscreen. Available on Youtube !

This study is also available in the GEOPOLYMER LIBRARY for free download. Go to #K-eng. Tiahuanaco geopolymer artificial stones

Extended Abstract

The first results of this research were published recently in leading international scientific journals:

1. On the geopolymer sandstone megalithic slabs: J. Davidovits, L. Huaman, R. Davidovits, “Ancient geopolymer in South American monuments. SEM and petrographic evidence “, Materials Letters 235 (2019) 120-124. DOI: doi.org/10.1016/j.matlet.2018.10.033, on line 8 October 2018.

2. On the geopolymer andesite volcanic “H” structures: J. Davidovits, L. Huaman, R. Davidovits, “Ancient organo-mineral geopolymer in South American Monuments: organic matter in andesite stone. SEM and petrographic evidence”, Ceramics International 45 (2019) 7385-7389, DOI: doi.org/10.1016/j.ceramint.2019.01.024, on line 4 January 2019.

The study carried out on the monumental stones constituting the Pumapunku site in Tiahuanaco, Bolivia, proves that the stones are artificial and are not carved with unknown technology or by extraterrestrials. It is the human genius, intelligently exploiting the resources of its environment, who created these marvels.

Tiahuanaco, on Lake Titicaca in Bolivia, is a village known throughout the world for its mysterious Gate of the Sun, ruins of temples and its pyramid. Archaeologists consider that this site was built well before the Incas, around 600 to AD 700. The site of Pumapunku is right next door with the ruins of an enigmatic pyramidal temple built at the same time. Because it is not restored and developed for touristic activity, it is less known to the general public. However, there are two architectural curiosities there: four giant red sandstone terraces weighing between 130 and 180 tons and small blocks of andesite, an extremely hard volcanic stone, whose complex shapes and millimetric precision are incompatible with the technology of the time. And for good reason, since archeology tells us that the Tiwanakans had only stone tools and no metal hard enough to carve the rock. But they would have carved the gigantic blocks of red sandstone (these ancient blocks are the largest of all the American continent!) and they were able to carry these hundreds of tons on the site, then to adjust them precisely. Also, they would have been able to carve other smaller blocks made of volcanic andesite, an impossible-to-carve stone with an incredible finish! Archaeologists cannot give any rational explanations on how this was possible. Therefore, for the general public, the assumptions generally advanced to explain these wonders are the achievement by a lost ancient super civilization or by aliens’ involvement.

In November 2017, the scientists gathered samples taken in the red sandstone and andesite from the Pumapunku site. For the first time, these stones were analyzed under the electron microscope, this had never been done before! They discovered the artificial nature of the stones. They compared the monuments’ stones with the local geological resources and found many differences.

Andesite rock is a volcanic stone from magma. It is composed mainly of silica in the form of plagioclase feldspar, amphibole and pyroxene. But the scientists have discovered the presence of an organic matter based on carbon. Carbon-based organic matter does not exist in a volcanic rock formed at high temperatures because it is vaporized. It is impossible to find it in andesite rock. And because we found organic matter inside the volcanic andesitic stone, the scientists will have the opportunity to carry out a Carbon-14 dating analysis and provide the exact age of the monuments. This organic element is a geopolymer based on carboxylic acids which was therefore added by human intervention into andesite sand to form a kind of cement.

The giant blocks of red sandstone raise another problem. Sandstone is a sedimentary rock composed of quartz grains and a clay binder. There are several possible geological sources but none correspond to the stones of the archaeological monuments. No known quarry is able to provide massive blocks of 10 meters long. In addition, the local stone is friable and small in size. The scientists have discovered under the electron microscope that the red sandstone of Pumapunku cannot come from the region because it contains elements, such as sodium carbonate, not found in the local geology. Therefore, where does the stone come from? From hundreds to thousands of kilometers? With what means have they been transported? In fact, electron microscopic analysis proves that the composition of the sandstone could be artificial (a ferro-sialate geopolymer) and manufactured to form cement.

What is this technology mastered by the Tiwanakans? Artificial stones were formed as cement. But, it is not a modern cement, it is a natural geological cement obtained by geosynthesis. For this, they took naturally friable and eroded rock like red sandstone from the nearby mountain, on the one hand, and on the other hand, unconsolidated volcanic tuff from the nearby Cerro Kapia volcano in Peru to form andesite. They created cement either from clay (the same red clay that Tiwuanakans used for pottery) and sodium carbonate salts from Laguna Cachi in the Altiplano Desert to the south, to form red sandstone. For gray andesite, they invented an organo-mineral binder based on natural organic acids extracted from local plants and other natural reagents. This cement was then poured into molds and hardened for a few months. Without a thorough knowledge of geopolymer chemistry, which studies the formation of these rocks by geosynthesis, it is difficult to recognize the artificial nature of the stones. This chemistry is not a difficult science to master. It is an extension of the knowledge of Tiwanakans in ceramics, mineral binders, pigments and above all an excellent knowledge of their environment. Without the selection of good raw materials, these extraordinary monuments could not have been created 1400 years ago.

Finally, this scientific discovery confirms local legends that say, “The stones were made with plant extracts able to soften the stone.” This explanation has always been rejected by archaeologists because it made no sense. The evidence provided by the team of scientists from France and Peru shows that the oral tradition was right: they made soft stones that could harden! The hypothesis of the lost ancient super civilization or alien intervention is false. Tiwanakuans were intelligent human beings. They knew their environment perfectly and knew how to exploit the resources brought by nature.

In addition to the Carbon-14 dating analysis, further studies will soon be carried out to determine whether certain monuments in the Cuzco region of Peru have been built with the same scientific knowledge.

This study is also available in the GEOPOLYMER LIBRARY for free download. Go to #K-eng. Tiahuanaco geopolymer artificial stones

Introduction

Preliminary results on Tiwanaku / Pumapunku monuments were recently published [1, 2]. Some of their methods of construction have long been a matter of interest and speculation involving super-civilizations or alien intervention. Conventional theories suggest that the constituent stone blocks were cut from quarries sometimes remotely located, accurately dressed and lifted into position. There is currently little research being done by material scientists on these controversial topics. However, from a construction and building material point of view, the knowledge that can be acquired through this type of archaeological study is manifold. In particular, it generates examples that are useful for the determination of the long-term properties of geopolymer concretes. It helps understanding of the chemical transformation which a geopolymer matrix can undergo over a long time range (hundreds if not thousands of years), and provides data on the crystallization mechanism and mineralogical evolution.

For the Egyptian pyramids, in the 1980s Joseph Davidovits, who is known for his development of geopolymer science and geopolymer concrete [3], proposed an alternative, but still controversial theory [4, 5]. He suggested that the blocks were a type of early concrete consisting of disaggregated limestone from the Giza plateau, Egypt, cemented by a sodium or potassium polysilico-oxo-aluminate, poly (sialate) geopolymer binder, and cast into blocks in situ. Despite the strong opposition of the Egyptian government [6], several scientists published studies which confirm the presence of archaeological geopolymer concrete in the pyramids [7, 8, 9, 10]. Civil engineers generally understand the implications resulting from this new paradigm of archaeological megalithic monument construction.

We present here our preliminary research results on monuments in the South American Andes, on the Altiplano (Fig. 1), namely Tiwanaku (in Spanish Tiahuanaco). It is located south-east of the Lake Titicaca at 3820 m above sea level. It comprises an earthen pyramid and the famous monolithic Gate of the Sun, made out of volcanic stone, andesite. They were built 1400 years ago (ca. AD 600) by the Tiwanaku Empire, one of the civilizations of the pre-Columbian Americas [11].

Our research focuses on the less known adjacent site of Pumapunku. In 2015 the Bolivian government started an ambitious project aimed at promoting this strange and little-known site. Its official report (2015-2020, C.I.A.A.A.T) reads (English translation from Spanish): ” … the upper platform of the pyramid presents the most astonishing vestiges. Huge [red sandstone] blocks, the largest in the monumental area of Tiwanaku, lie scattered as if a large earthquake had devastated the area. The large blocks of red sandstone, mixed with fragmented doors in andesite, covered with carved decorations, is all that can be distinguished today. The ashlars with geometrical and symmetrical reliefs, perfectly polished are the silent witnesses of those majestic and important constructions of Pumapunku in the past”.

Fig. 2 is the tentative reconstruction of the site. The sandstone temple itself is very small. The platform on top of the 4-step pyramid of Pumapunku consists of 4 megalithic red sandstone slabs marked in red Nr 1, Nr 2, Nr 3, Nr 4, weighing between 130 and 180 tonnes each (Fig. 3), the largest among the New World monuments. In recent years, several reports and videos have been flourishing on the Internet. Some civil engineers state that the monuments are made of a type of concrete. Others claim that they were built by super-civilizations with unknown technologies. Our study suggests that the slabs are a type of sandstone geopolymer concrete cast on the spot. There are no quarries in the vicinity whence the megalithic blocks used in the monument could have been brought in.

One early Spanish conquistador chronicler, Pedro de Cieza de Leon, who visited Lake Titicaca on the Altiplano in 1549, marveled over the ruins of Pumapunku, wondering what tools could have been used to achieve such perfection (English translation [12]) ” In another, more to the westward [of Tiwanaku], there are other ancient remains, among them many doorways, with their jambs, lintels, and thresholds, all of one stone. But what I noted most particularly, when I wandered about over these ruins writing down what I saw, was that from these great doorways there came out other still larger stones upon which the doorways were formed, some of them thirty feet broad, fifteen or more long, and six in thickness. The whole of this, with the doorway and its jambs and lintel, was all one single stone. The work is one of grandeur and magnificence when well considered. For myself I fail to understand with what instruments or tools it can have been done; for it is very certain that before these great stones could be brought to perfection and left as we see them, the tools must have been much better than those now used by the Indians (….) Another remarkable thing is that in all this district there are no quarries whence the numerous stones can have been brought, the carrying of which must have required many people. I asked the natives whether these edifices were built in the time of the Incas, and they laughed at the question, affirming that they were made before the Incas ever reigned, but that they could not say who made them….” According to modern archaeology, the monument was destroyed around AD 900, i.e. 500 years before the rise of the Inca Empire.

The most controversial aspect of the Pumapunku site is, however, found in puzzling smaller items, 1 meter high, made of andesitic volcanic stone (Fig. 4). They have unprecedented smooth finishes, perfectly flat faces at exact 90° interior and exterior right angles. Historian architects are wondering how such perfect stonework could have been achieved with simple stone tools [13]. Our study demonstrates that these architectural components were fashioned with a wet-sand geopolymer molding technique.

Part 1:

Pumapunku red sandstone megaliths

1.1 Geological provenience of the megalithic sandstone blocks

Travelers mostly agreed that the sandstone was mainly from the Kimsachata mountain range south of Tiwanaku. Yet, it remained unclear how these megaliths were quarried and transported downwards with primitive sledges on steep and narrow llama tracks as shown in Fig. 7. The first scientific studies conducted and published in the early 1970s by Bolivian archaeologists [14], set out to determine the source of the sandstone employed to construct the Pumapunku complex. They conducted geological studies in 6 drainage valleys, isolating several potential sandstone quarries, totalizing 47 samples. With comparative investigations including X-ray diffraction, XRF, geochemical analysis, and lithic petrography, they concluded that Pumapunku sandstone came from the Quebrada de Kausani (geological site (1) in Fig. 6). However, our detailed study of their published chemical analysis contradicts this.

In 2017, we took this 1970 study to start our investigation and selected three sites (Fig. 6): site (1) Quebrada de Kausani, site (2) Cerro Amarillani, already studied in the 1970s but not selected, and we added a third site, site (3), Kallamarka. Why? Because there exist several archaeological records in the village of Kallamarka, which show that the village was in activity at the time of Pumapunku construction. It is therefore clear that this village could have been associated with the sandstone material extraction. It was recently declared part of World Heritage by UNESCO in June 2014 (see below).

1.1.1 Quebrada de Kausani (KAU)

The visit to the site number (1) Quebrada de Kausani starts from the Altiplano plateau at 3850 meters and climbs up to a place called Kaliri at 4159 meters above sea level. Official archaeology is claiming that they used the steep llama track (Fig. 7) for dragging their 150 tons megaliths down to the valley. This is difficult to believe.

On the plateau, at Kaliri, there are numerous quadratic sandstone blocks lying on the ground, but we don’t find any massive blocks. We have only small blocks (Fig. 8). American archaeologists [15] are claiming that these are the remains of human quarrying activity. Bolivian archaeologists are telling no, there are not! In 1970, they wrote: “typical process of disintegration by mechanical weathering (…) there were no actual sandstone quarries used by the Tiwanacotas, such as an open pit, work or gallery, but instead they went to blocks separated by diaclasis.” This is a geological natural weathering event. It happens that it is producing quadratic blocks, like in other sandstone locations.

1.1.2 Cerro Amarillani (AMA)

The site number (2) Cerro Amarillani is easier to reach by car and road. It is a similar geological formation. We have also blocks. (Fig. 9)

1.1.3 Kallamarka (MAR)

The site number (3) Kallamarka (Kalla Marka) is totally different. Callamarca is the spelling in Spanish. Kallamarka with “k” is the spelling in the local language. The entrance of the village is typical and is not found elsewhere (Fig. 10). It suggests an historical background. It is astonishing clean, with a road pavement made of bricks. In fact it pertains to the famous Inca track, Qhapaq Ñan, Andean Road System, declared part of the World Heritage by UNESCO, in June 2014.

We continue our trip on the earthen road by car and leave the village, climbing up and arriving at the site that had been selected by our geologist. There, we find individual sandstone blocks, but more interesting, we have a particular feature here, namely layers of weathered soft sandstone, good for geopolymer reaction, lying in between of the quadratic blocks like displayed in Fig. 11 left.

Our geologist undertook the following experimentation on the site (Fig. 11 right) (watch the video for details) . “As you can see: you can take a very simple tool, break the sandstone down in smaller pieces, very easily…; this could be a good material to make geopolymer stone. …yes, very easy. Even with our hands we can grind it down. It’s very easy.”

1.1.4 Taking monument sample PP4.

The Pumapunku monument red sandstone labeled PP4 and studied here is from slab No. 2. In Fig. 5, the sampling location is marked by a black dot. In Fig. 12, it is highlighted with an arrow. It is taken from an already ancient fractured place, on the edge of the slab, where several fragments had been selected and studied in the 1970s by the Bolivian archaeologists, see the sample labeled Nr 9 (circle).

Both samples (1970 and 2017) can be compared with respect to chemical makeup and petrographic analysis.

1.2 Scientific investigations: thin sections, optical microscope. X-rays diffraction, SEM / EDS, scanning electron microscope.

1.2.1 Optical microscope: thin sections

The thin 30 µm thick sections were studied under transmitted polarized light with a Leica 4500 DMP optical microscope. The results for sandstone are shown in Fig. 13-15; the thin sections are marked KAU (Kausani), AMA (Amarillani), MAR (Kallamarka) and PP4 (Pumapunku fragment No. 4).

1.2.2 Chemical (EDS) and XRD analysis.

The scanning electron microscope SEM / EDS analysis for the elements were acquired using a JEOL JSM-6510LV scanning electron microscope. X-ray diffraction spectra were acquired using a XD8 Advance “BRUKER” AXS (Siemens) spectrometer, calibrated and interpreted according to ICDD/COD international databases from 2013. The semi-quantitative results for sandstone are listed in Table 1: chemical composition (elements at.%) and XRD mineralogical composition. KAU has quartz SiO₂ and feldspar albite NaSi₃AIO₈, AMA has quartz and feldspar anorthite Ca (SiAIO₄)₂, and both MAR and PP4 have quartz and feldspar albite. We find additional minerals in MAR, namely calcite CaCO₃, kaolinite and illite clays.

In Table 1, X-ray fluorescence and SEM/EDS analysis show that the KAU sample has neither B (boron) nor Ca. Later values confirm the chemical analysis of the 1970s [14] in which for 6 Kausani samples, CaO = 0%, whereas for 20 monument samples, CaO = 1.45 (medium value). In Table 1, for PP4-global, Ca = 1.70. In addition, for PP4-global, Na at.% = 9.95; this is substantially higher than for KAU (6.67), AMA (1.56) and MAR (5.10). This value is important and will be discussed below.

Table 1: Element (at.%) and mineralogical analyses for Pumapunku red sandstone and geological sandstone. X-ray fluorescence data for B boron are taken from reference [14], after [1].

Chemical analysis, XRF, XRD analysis (Table 1) and thin sections (Fig. 13-15) suggest that KAU and AMA are dissimilar to PP4, i.e. that the stone material PP4 of the monument does not originate from KAU (Kausani) or AMA (Amarillani) geological sites.

1.2.3 SEM analysis.

The high amount of Na measured for PP4-global in Table 1 relates to the SEM image and EDS spectrum of Fig.16, showing authigenic albite NaSi₃AIO₈ formed after consolidation of the sandstone. In natural sandstone, after millions of years of consolidation, the authigenic albite results from the permeation of weak alkaline waters and dissolution of the feldspar. But this requires high pressures (between 3,600 and 5,000 m depth) and temperatures (100 to 150° C) [16]. Usually, these are big crystals. Here we have a very thin uniform layer. It could be the result of the self-crystallization of a polysialate geopolymer, Si/Al=3. Because, in a Na-poly (sialate) geopolymer-based sandstone concrete, the alkaline concentration is high, the albite formation and crystallization might occur during a relatively shorter time, namely through the 1400 years of archaeological burial. But, with our present knowledge, we cannot differentiate between natural authigenic and geopolymer albite.

1.3 Discussion

Kaolinite clay is one of the major minerals commonly found in geopolymer synthesis and the manufacture of geopolymer concrete. MAR sandstone is subject to weathering actions transforming the feldspar into kaolinite. It is readily disintegrated into small pieces manually as shown in Fig. 11. The kaolinite quantities (in the 7% weight range) detected by the XRD analysis for MAR are high enough to start geopolymerization, provided it is combined with an alkaline medium (Na or K).

But MAR also contains calcite CaCO₃, not found in PP4. However, the weathering action may vary from place to place. The Kallamarka plateau covers a large area and subsequent work on samples from this site may produce XRD spectra more similar to the present PP4 spectrum. This differentiated weathering action suggests that, in order to manufacture one of the big monument slabs, weighing up to 180 tonnes, the sandstone material could have been dug up at different locations, i.e., with different calcite content. Indeed, the petrographic analysis of the 1970s carried out on the four megalithic slabs found calcite in 15 samples, yet none in 5 others, out of a total of 20. For their two samples M9 and M12 taken in the same slab No. 2, the calcite content for M9 = 0%, whereas M12 = 12%. So, the calcite content is varying within the same sandstone block. Since our specimen PP4 was taken at the same place as the sample M9 of slab No. 2 in Fig. 5 and Fig. 12, our XRD result is correct.

In Fig. 15, the thin sections for PP4-1 and PP4-2 show the thick fluidal red ferro-sialate matrix labeled GP (white arrows) and detected with SEM in Fig. 17. To our knowledge, this feature is very unusual in sandstone formed geologically or at least it has not been reported in petrographic studies performed in the red sandstone of the area [14] [18]. The thick fluidal red ferro-sialate GP matrix displayed in Fig.17 represents a unicum and supports the idea of an artificial sandstone geopolymer concrete.

In Table 1 the Na content for PP4 global and PP4 matrix is also higher than the values for KAU, AMA and MAR. Therefore, in the assumption that PP4 is natural sandstone, it does not belong to the sandstone from the Kimsachata mountain range south of Tiwanaku. None of the analysis carried out on the 47 samples studied in 1970 contains this high amount of Na. Where does it come from? Sandstone with such a high Na content has not been located in the vicinity, so far. Therefore, if we stay with the accepted argument that the monument sandstone is natural, then, it does not belong to the region. Consequently, according to traditional archaeology, the megalithic slabs of between 130 and 180 tonnes, would have been extracted and moved from a geological site located elsewhere, far away. These giant sandstone blocks, the size of a house (8×8 meters surface area), would have been transported on primitive sledges downwards from a place similar to the KAU Kausani site located at 4150 meters altitude on a steep and narrow llama track as shown in Fig. 7. This is difficult to accept even though archaeologists have experimented with dragging small pillars (1 to 5 tonnes) on level ground.

However, if we accept the idea that the MAR Kallamarka site, which contains kaolinite clay, is the source for the monument sandstone, then an additional alkaline hardener is needed in the stone geopolymer slurry, for example the salt natron, Na₂CO₃ extracted from Laguna Cachi, a small lake (salar) in the Altiplano Desert (Bolivia). According to archaeological records, llama caravans went through Laguna Cachi. This suggests that the salt natron was exploited by the ancient builders of Pumapunku / Tiwanaku, 1400 years ago. The extraction of this salt has continued even in modern times.

If we examine all the aforementioned arguments, we come to the conclusion that the monument stone consists of sandstone grains from the Kallamarka site, cemented with a ferro-sialate geopolymer matrix formed by human intervention.

2. Pumapunku

gray andesite volcanic structures

2.1 Extravagant and puzzling structures.

We mentioned in the Introduction that the most controversial aspect of the Pumapunku site is, however, found in puzzling smaller items, 1 meter high, made of andesitic volcanic stone, the “H” sculptures in Fig. 4 and others like in Fig.18 and Fig. 19.

2.1.1 Perfect 90° angle cutting, very smooth.

They have unprecedented smooth finishes, perfectly flat faces at exact 90° interior and exterior right angles. How were such perfect cuts made with simple stone tools? They have a Mohs hardness of 6 to 7, like quartz and, even those archeometrics people who are claiming that these artifacts were manufactured by an ancient civilization 30,000 or 60,000 years ago, don’t have the tool to replicate them.

2.1.2 An archeologist who says we don’t know !

Archaeologists try to explain how such perfection could be achieved with simple hammerstones. However, one expert strongly disagrees. For historian architects, the making of the “H” sculptures remains a riddle which they cannot solve. Protzen et al. [13] explained their dilemma and stated: “(…) to obtain the smooth finishes, the perfectly planar faces and exact interior and exterior right angles on the finely dressed stones, they resorted to techniques unknown to the Incas and to us at this time. (…) The sharp and precise 90° interior angles observed on various decorative motifs most likely were not made with hammerstones. (…) No matter how fine the hammerstone’s point, it could never produce the crisp right interior angles seen on Tiahuanaco/Pumapunku stonework. Comparable cuts in Inca masonry all have rounded interior angles typical of the pounding technique (…) The construction tools of the Tiahuanacans, with perhaps the possible exception of hammerstones, remain essentially unknown and have yet to be discovered.”

Our long experience in geopolymer technologies suggests that these sculptures can be very easily manufactured with the molding technique. Wet-sand molding technique, i.e., the pounding of semi-dried geopolymer mortar inside a mold, would produce the very fine and precise surface as well as the sharp angles. Fig. 20 displays all the features of an item that was obtained by pounding wet sand in a mold. The weathering action reveals a dense skin (Fig. 20A), a very precise surface, clean, flat and dotted with small bubbles, the semi-spherical air bubbles which had been trapped against the mold (Fig. 20B). Another method is to first make a preform by molding, then carve the interior before it hardens, with an obsidian tool for example.

2.2 Scientific investigation: thin sections, optical microscope, SEM/EDS, scanning electron microscope

The Bolivian scientists who carried out the investigation in the 1970s did not perform any similar petrographic study on the andesitic volcanic sculptures. Nineteenth-century travelers had agreed that the andesite stone originated mainly from the volcano Cerro Khapia in the southern part of the Lake Titicaca [19]. More recently Janusek et al. [15] confirmed that the volcano was the principal source of andesitic material at Pumapunku / Tiwanaku. However, they did not perform a regular petrographic study. They relied on qualitative results obtained on volcanic boulders with a portable X-ray fluorescence spectrometer, and not on quarrying remains. This explains why, in this preliminary study, we do not compare geological andesite and monument stone, as we have done with sandstone. In the absence of a geological study, we did not know where to look.

2.2.1 Andesite monument samples.

We mentioned in the Introduction that numerous andesite fragments, heaps of rubbles, are scattered on the site and abandoned. They are outside the protected monument area. By carefully choosing this debris consisting in fact of pieces of monumental stones with the characteristically very flat surface, we were able to get our representative samples. Samples PP1 A and B (Fig 21) are the most important for our study. The sample PP2 was taken at the corner of a broken door fragment and PP5 on the surface of a flat slab.

2.2.2 Optical microscope: thin sections.

In the thin section displayed in Fig. 22 we see, in white, the minute plagioclase feldspar crystals, the large amphibole crystals and pyroxene. In addition, we have black areas of amorphous substance that run across the entire picture.

Under reflecting light, the surface of PP1A shows white feldspar plagioclase crystals and dark elongated minerals which are typical for this type of andesite stone (Fig. 23). The surface is very flat, without any trace of polishing action with abrasive grains nor cutting tool, but dotted with small holes that are 0.2 to 0.5 mm deep with clear edges.

No. 1: plagioclase phenocryst on the surface;

No. 2: mica biotite single crystal on the surface;

No. 3: pyroxene-augite crystal on the surface;

No. 4: hole with hornblende crystals, pyroxene-augite crystal and amorphous matter (see description below);

No. 5: hole with minute feldspar plagioclase crystals;

No. 6: hole with pyroxene and amphibole crystals.

The surface of the andesite stone is hard, with a Mohs hardness of 6-7 (7=quartz), and the density is d=2.58 kg/l. [17].

2.2.3 SEM / EDS analysis.

Now we focus on hole number 4 (Point 4) already mentioned above in Fig. 23, with a higher magnification (optical microscope).

At higher magnification, in Fig. 25, we have a surprising totally amorphous element that resembles rubber, and is not like a crystalline mineral. Is this the amorphous matter already mentioned above in the thin section of Fig. 22 ?

Surprisingly, we are finding organic matter in a volcanic rock. This is unusual and simply contrary to nature. We can only conclude that this sample is artificial, man-made.

It could be argued that, since this is a SEM image that was taken from a hole located on the surface of sample PP1, what we had been measuring was the result of surface pollution. Therefore, in order to deal with this argument, we looked inside PP1A by cutting from its interior a smaller sample labeled PP1C. We obtained several spots with the same type of organic matter. Fig. 27 displays two of them.

2.3 Discussion: which chemistry ?

Everybody will agree with the fact that this organic matter suggests the presence of an artificial stone. So, first conclusions: which chemistry? It is not polysialate-based geopolymer like for the red sandstone megaliths. It is not the alkaline medium. If it is not alkaline medium, then it is acidic medium. And yes, this is acidic medium if we rely on the ancient legends that archaeology doesn’t take into account: “(…) una sustancia de origen vegetal capaz de ablandar las piedras“. Plant extracts capable of softening stones. This is what the local South American people are telling and reading.

2.3.1 Plant extracts capable of softening stones: carboxylic acids.

40 years ago, Prof. Joseph Davidovits met with a Peruvian anthropologist, Francisco Aliaga, and they decided to make one presentation at an archaeometrical conference in New York, 1981 [20], titled: “Fabrication of Stone Objects by Geopolymeric Synthesis in the Pre-Incan Huanka Civilization in Peru“. The excerpt of the Proceedings summary reads: “It is now agreed that the Tiwanaku civilization is modeled on the pre-Incan Huanka civilization revealed by an extraordinary skill in fabricating objects in stones. A recent ethnological discovery shows that some witch doctors in the Huanka tradition, use no tools to make their little stone objects, but still use a chemical dissolution of the stone material by plant extracts, carboxylic acids.”

One year later, in 1982, a scientific study carried out with the Laboratory of Pharmacognosy in Grenoble University, France, was published with the title: “The Disaggregation of Stone Materials with Organic Acids from Plant Extracts, an Ancient and Universal Technique.” The study focused on the extraction of carboxylic acids from plants and their degrading action of limestone (calcium carbonate). The conclusion of the study stated: “..the pre-columbian farmers were quite capable of producing large quantities of acid from such common plants in their region as: fruits, potatoes, maize, rhubarb, rumex, agave Americana (this is the cactus), ficus indica, oxalis pubescens.” [21] [22].

They studied the action of three carboxylic acids:

• acetic acid,
• oxalic acid,
• citric acid.

These carboxylic acids work perfectly with limestone. Limestone is disaggregated by these organic acids. It is very easy to prove and to measure their action. Any stone that contains limestone will be disaggregated but not volcanic andesite. It doesn’t work. This chemistry can only be used to fabricate a binder, which, as such, will agglomerate non-consolidated stone material (for example volcanic sand). So, clear-cut between limestone and volcanic stone such as the andesite.

2.3.2 We could disaggregate limestone, but we were not able to re-agglomerate, harden it.

Several people tried to discover the secret of this stone making. They were successful in softening the limestone that they reduced to a soft mass. But they failed to harden it again. This has been the reason, why, 40 years ago, Davidovits and Aliaga stopped their studies. They could disaggregate (limestone) but they were not capable to re-agglomerate it, to harden it again.

The appropriate knowledge was acquired very recently (2 years ago). It applies the basic chemistry dealing with Phosphate-based geopolymers and Organic-mineral geopolymers [23].

2.3.3. Research target, finding the hardener: the guano.

Where can we find, locally, the chemicals that will generate this chemistry? For sandstone we located the alkaline Natron in the Altiplano lake Laguna Cachi, to manufacture the big megaliths. For the volcanic andesite stones, we have an organic binder obtained in an acidic medium, and we are looking for the hardener.

Archaeology is providing diverse hints that are relying on several texts written during the Spanish conquest. They transcribe the explanations provided orally by the native people at that time. One of these texts is dealing with the guano trade between the Pacific Ocean at Ilo and Tiwanaku, going up from the sea level to 3800 meters high (Fig. 28). It has been discussed by J.W. Minkes [24]. The excerpt of the study starts with the site of Ilo on the Pacific Ocean and reads: “5.5.2 El descanso: El Descanso means the ‘resting place’ in Spanish. This name has been transmitted orally and refers to the traditional use of the site as resting place for the llama caravans on their way to or from the highlands via Moquegua…” According to the historical documents, the Moquegua Valley was the route taken by numerous Llama caravans carrying the guano gathered in large quantities at Punta Coles, Ilo, upwards to Tiwanaku. This trade [guano] appears to have been intensified during the Tiwanaku / Pumapunku construction, possibly stimulated by the need for more guano. The coastal [Ilo] population received coca, camelid wool, dried meat as well as llamas for guano transportation in exchange.

The guano is an excellent fertilizer but we think that this is not the reason why they transported it to the highlands. The Tiwanaku civilization was created before they exploited the guano. At Tiwanaku, they had already developed a very special agriculture known as raised-field system. The fields consisted of elevated, elongated planting beds, surrounded by water-filled ditches. The ditches contained aquatic plankton and small fishes which provided a natural fertilizer [25]. They did not need the guano, because they produced on site their own fertilizer. So, to claim that the guano had been sent to the highlands because they needed it as a fertilizer for the agriculture is not correct. This civilization was developed by itself. We suspect that this guano was not used in agriculture (the exploited quantities are much greater than what would be needed for agriculture alone), but rather, could be one geopolymer organic hardener. Indeed, it contains different chemical ingredients useful for that purpose.

Table 2 displays an analysis that was carried out 150 years ago by Mr. J.D. Smith on specimens of Peruvian guano [26]. It contains a high number of salts of acids, essentially ammonium oxalate and urate, calcium oxalate, ammonium phosphate and calcium phosphate.

Table 2: chemical composition of Peruvian guano containing essentially: ammonium oxalate and urate, calcium oxalate, ammonium phosphate and calcium phosphate after [26].

The action of vinegar (acetic acid) or any of the other carboxylic acids extracted from plants, on the guano, yields the formation of phosphoric acid and oxalic acid, useful in the production of phosphate-based geopolymer. The chemistry also involves the addition of alumino-silicate minerals such as finely weathered volcanic tuff, kaolinitic clay or perhaps metakaolin. New research on site is needed in order to determine which mineral was taking part in the making of this organo-mineral geopolymer binder.

2.3.4 EDS of guano compared with PP1 organic matter.

The EDS analysis of the guano sample from Ilo, displayed in Fig. 29, is similar to the EDS of the PP1 / point 4 organic matter (see in Fig. 25-26). The chemical elements are identical, yet, they are present at a lower concentration in the monument, which seems to be obvious. However, at the stage of our present study we do not know whether the PP1 organic matter is the remaining part of unreacted guano or the spectrum of the organo-mineral binder itself.

2.3.5 First conclusion.

The organic matter detected in this study suggests the reaction of an ammonium organic compound (the nitrogen N) from vegetal or animal origin, with minerals, to form an organo-mineral binder. The quantitative analysis of the nitrogen N cannot be carried out with our present equipment. We only got semi-quantitative data. The detection of Cl, P and S is intriguing and could provide some clues for further research. The builders may have transported non-consolidated volcanic andesite tuff having the consistence of sand, from the Cerro Khapia site. They added a type of organo-mineral binder manufactured with local biomass (carboxylic acids extracted from maize and plants), guano and reactive alumino-silicate minerals.

3. Conclusion

The thin section of a sample taken from the Pumapunku red sandstone monument shows grain boundaries made of a thick fluidal red ferro-sialate matrix. To our knowledge, this feature is very unusual in sandstone formed geologically. It represents a unicum and supports the idea of artificial sandstone geopolymer concrete. Complementary SEM/EDS analysis for Na, Mg, Al, Si, K, Ca, Fe suggests that the Kallamarka site is the source for Pumapunku megalithic blocks. The megalithic slabs of between 130 and 180 tonnes were cast 1400 years ago. To make their geopolymer sandstone concrete, the builders may have transported finely weathered, kaolinitized sandstone from the Kallamarka site and added foreign elements such as natron (Na₂CO₃) extracted from Laguna Cachi, a small lake (salar) located south of the great Salar de Uyuni, in the Altiplano (Bolivia).

However, the most controversial aspect of the Pumapunku site is found in puzzling smaller items made of andesitic volcanic stone. Our study demonstrates that these architectural components were fashioned with a wet-sand geopolymer molding technique. The SEM study of this gray andesite shows the presence of organic matter (it could be the geopolymer binder). We have carbon, nitrogen, and mineral elements. The existence of amorphous organic matter is very unusual, if not impossible in a volcanic stone. It was also detected in the optical thin sections studies. It is a “unicum” and supports the idea of artificial andesite geopolymer concrete. To make geopolymer andesite concrete, the builders may have transported non-consolidated volcanic tuff, which is an andesite stony material having the consistence of sand from the Cerro Khapia site, and added an organo-mineral geopolymer binder manufactured with local ingredients.

Surprisingly, this study demonstrates that the Pumapunku builders mastered two geopolymer concrete methods, namely:

a) – One in alkaline medium for the red sandstone megaliths. This technology is familiar to modern material scientists and civil engineers, and is in line with knowledge of the traditional method of producing geopolymer concrete.

b) – The second, in acidic medium for the gray andesite structures, is based on the use of organic carboxylic acids extracted from local biomass and also the addition of guano. It has been successfully replicated in our laboratory with modern chemicals in order to test the validity of the chemical mechanisms involved in the new geopolymeric reactions.

In the absence of contrary evidence, the present conclusions are sound, and the Pumapunku red sandstone megalithic slabs and gray andesite sculptures are made of ancient geopolymers. This kind of study could provide data on the long-term crystallization mechanisms and mineralogical evolution of geopolymer molecules. In addition, the next step of our study will be to gather enough sample in order to implement Carbon-14 dating and provide the exact age of the monuments.

Acknowledgements

SEM data were collected by Mathilde Maléchaux at Pyromeral Systems SA. 60810 Barbery. France; thin sections were made at UniLaSalle-Geoscience. 6000 Beauvais. France. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

References:

[1] J. Davidovits, L. Huaman, R. Davidovits, Ancient geopolymer in South American monument. SEM and petrographic evidence, Material Letters 235 (2019) 120-124. DOI: doi.org/10.1016/j.matlet.2018.10.033.

[2] J. Davidovits, L. Huaman, R. Davidovits, Ancient organo-mineral geopolymer in South American Monuments: organic matter in andesite stone. SEM and petrographic evidence, Ceramics International, 45 (2019) 7385-7389. DOI: doi.org/10.1016/j.ceramint.2019.01.024.

[3] J. Davidovits, Geopolymers: inorganic polymeric new materials, J. Thermal Analysis, 37 (1991), 1633–1656.

[4] J. Davidovits. X-ray analysis and X-ray diffraction of casing stones from the pyramids of Egypt. and the limestone of the associated quarries. in: A.R. David (Eds), Science in Egyptology symposium, Manchester University Press (1986) 11–20.

[5] J. Davidovits, Ancient and modern concretes: what is the real difference?, Concrete International: Des. Constr, 9[12] (1987), 23–29.

[6] C. Nickerson, Did the Great Pyramids’ builders use concrete?, The New York Times, April 23, 2008, https://www.nytimes.com/2008/04/23/world/africa/23iht-pyramid.1.12259608.html, (accessed 10 August 2018).

[7] G. Demortier, PIXE, PIGE and NMR study of the masonry of the pyramid of Cheops at Giza, Nuclear Instruments and Methods in Physics Research B, B 226, (2004) 98–109.

[8] M.W. Barsoum, A. Ganguly and G. Hug, Microstructural Evidence of Reconstituted Limestone Blocks in the Great Pyramids of Egypt, J. Am. Ceram. Soc. 89[12] (2006), 3788–3796.

[9] K.J.D. MacKenzie, M.E. Smith, A. Wong, J.V. Hanna, B. Barry, M.W. Barsoum, Were the casing stones of Senefru’s Bent Pyramid in Dahshour cast or carved? Multinuclear NMR evidence, Materials Letters 65 (2011) 350–352.

[10] I. Tunyi and I. A. El-hemaly, Paleomagnetic investigation of the Pyramids, Europhysics News 43/6 (2012), 28-31.

[11] A. Vranich, Reconstructing ancient architecture at Tiwanaku, Bolivia: the potential and promise of 3D printing, Heritage Science 6/65 (2018), DOI: doi.org/10.1186/s40494-018-0231-0.

[12] C. R. Markham, Travels of Pedro de Cieza De Leon A.D. 1532-50, Hakluyt Society, London (1864), 376-379.

[13] J.-P. Protzen and S. Nair, Who Taught the Inca Stonemasons Their Skills? A Comparison of Tiahuanaco and Inca Cut-Stone Masonry, Journal of the Society of Architectural Historians, 56/2 (1997), 146-167.

[14] C. Ponce Sangines. A. Castanos Echazu. W. Avila Salinas. F. Urquidi Barrau. Procedencia de las areniscas utilizadas en el templo precolumbio de Pumapunku (Tiwanaku). Academia Nacional de Sciencias de Bolivia (1971) No.22.

[15] J. W. Janusek, P. R. Williams, M. Golitko, and C. Lémuz Aguirre, Building Taypikala: Telluric Transformations in the Lithic Production of Tiwanaku, in: N. Tripcevich and K.J. Vaughn (eds.), Mining and Quarrying in the Ancient Andes, Interdisciplinary Contributions to Archaeology, Springer Science+Business Media, New York, 2013, pp. 65-97.

[16] N. Mu. Y. Fu. H.M. Schulz. W. van Berk. Authigenic albite formation due to water–rock interactions — Case study: Magnus oilfield (UK. Northern North Sea). Sedimentary Geology 331 (2016) 30–41.

[17] J. Davidovits. Geopolymers: Ceramic-like inorganic polymers. J. Ceram. Sci. Technol. 08 [3] (2017) 335-350.

[18] O. Palacios. Geology of the Western and Altiplano Mountains west of Lake Titicaca in southern Peru. Bulletin A42 (1993) 80p.

[19] A Stübel and M. Uhle, Die Ruinenstäette Von Tiahuanaco, Verlag von Karl W. Hiersemann, Leipzig, 1892. http://digi.ub.uni-heidelberg.de/digit/stuebel_uhle1892/0004, (accessed 10 August 2018).

[20] J. Davidovits, F. Aliaga, Fabrication of Stone Objects by Geopolymeric Synthesis in the Pre-Incan Huanka Civilization in Peru, Abstracts of 21st International Symposium for Archaeometry, Brookhaven National Laboratory, New York, USA (1981) page 21.

[21] J. Davidovits, A. Bonett and A.M. Mariotte, Proceedings of the 22nd Symposium on Archaeometry, University of Bradford, Bradford, U.K. March 30th – April 3rd (1982), 205 – 212.

[22] The pdf files of ref. 20 and 21 are in the Geopolymer Institute Library for free download, called Making Cement with Plants Extracts, at #C: //www.geopolymer.org/library/archaeological-papers/c-making-cements-with-plant-extracts/ .

[23] See Chapter 13 and Chapter 14, in J. Davidovits, Geopolymer Chemistry and Applications, Edition: 2nd (2008), 3rd (2011), 4th (2015), Publisher: Institut Géopolymère, Geopolymer Institute, Saint-Quentin, France, Editor: ISBN: 9782951482098 (4th ed.)

[24] J.W. Minkes, Wrap the Dead, Archaeological Studies Leiden University, 12, (2005), Chapters 5.5.2, 6.5.2.

[25] A.L. Kolata, The technology and organization of agricultural production in the Tiwanaku State, Latin American Antiquity, 2(2) (1991), 99-125.

[26] J. Towers, Guano and its analysis, The British Farmer’s Magazine, (1845) Vol. 9, 389-400.

This study is also available in the GEOPOLYMER LIBRARY for free download. Go to #K-eng. Tiahuanaco geopolymer artificial stones

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

False Values on CO₂ Emission for Geopolymer Cement/Concrete Published in Scientific Papers

Adapted from the article originally published in Elsevier’s internet site “Materials Today” at Environmental Implications of Geopolymers, 29 June 2015. See also the presentation at the Geopolymer Camp 2015. See also the news Virtual Journal on Geopolymer Science .

LCA of commercialised geopolymer cement/concretes are seldom. This is due to proprietary reasons. Presently they are based on Type 2 slag/fly ash/alkali-silicate system (see Technical papers #21, #22, #23 in the Library). Geopolymer Type 2 concrete and standard Portland concrete are similar in non- binder materials used and behaviour after production; there is some dilution of the benefits when measured over the full life cycle (LCA). The greenhouse gas emissions during the life cycle of Geopolymer Type 2 concrete are approximately 62%-66% lower than emissions from the reference concrete. The Type 2 geopolymer cement has ca. 80% lower embodied greenhouse gas intensity than an equivalent amount of ordinary Portland cement binder used in reference concrete of a similar strength, confirming the data published by the Geopolymer Institute, where the reductions are in the range of 70 % to 90 % (see Technical paper #21). These values do not include any additional external constraints like transport from or to the utility. They reflect the actual potential as soon as industrialization starts in full swing.

On the opposite, several published scientific LCA papers claim that, in terms of CO₂ emission, geopolymer cement was not better than Portland cement, and worse for other parameters. These statements are based on methodological errors and false calculations of the CO₂ emission values for geopolymer cement/concrete. The problem is that these false values are taken for granted by other scientists without any further consideration.

The present paper “False Values on CO₂ Emission for Geopolymer Cement/Concrete Published in Scientific Papers” cites and explains the methodological errors and false calculations.

Click here to see how to download paper nr 24 False-CO2-values.pdf.

Brisbane West Wellcamp Airport (BWWA), Toowoomba, Queensland, is Australia’s first greenfield public airport to be built in 48 years. BWWA became fully operational with commercial flights operated by Qantas Link in November 2014. See our News dated of October 14, 2014, 70,000 tonnes Geopolymer Concrete for airport.
This project marks a very significant milestone in engineering – the world’s largest geopolymer concrete project. BWWA was built with approximately 40,000 m3 (100,000 tonnes) of geopolymer concrete making it the largest application of this new class of concrete in the world. The geopolymer concrete developed by the company Wagners, known as Earth Friendly Concrete (EFC), was found to be well suited for this construction method due to its high flexural tensile strength, low shrinkage and workability characteristics. Heavy duty geopolymer concrete, 435 mm thick, used for the turning node, apron and taxiway aircraft pavements, welcomes a heavy 747 cargo for regular air traffic between Toowoomba-Wellcamp BWWA airport and Hong Kong. For technical details read the paper by Glasby et al. (2015), EFC Geopolymer Concrete Aircraft Pavements at Brisbane West Wellcamp Airport, in our Library, Technical paper #23 GP-AIRPORT. Technical Paper on Geopolymer Aircraft Pavement

Prof. Joseph Davidovits’ visit to the Toowoomba-Wellcamp-Airport.

On October 3, 2015, Joseph and Ralph Davidovits flew from Sydney Airport to Toowoomba-Wellcamp-Airport, for a visit to the company Wagners.

Prof. Joseph Davidovits’ visit to the Global Change Institute, Brisbane, Queensland, Australia.

On October 7, 2015, Joseph and Ralph Davidovits drove with Tom Glasby and Russell Genrich, company Wagners, from Toowoomba to Brisbane. Our News dated December 10, 2013, was titled World’s first public building with structural Geopolymer Concrete. It introduced the world’s first building to successfully use geopolymer concrete for structural purposes, the Global Change Institute, University of Queensland, Brisbane, Queensland, Australia. The 4 story high building, for general public use, comprises 3 suspended geopolymer concrete floors involving 33 precast panels. They are made from slag/fly ash-based geopolymer concrete coined Earth Friendly Concrete (EFC), a Wagners brand name for their commercial form of geopolymer concrete.

A recent Technical Paper #24 denounces the false values on CO₂ emission published in several scientific papers. See at “False CO₂ values published in scientific papers“.

Geopolymer cement is often mixed up with alkali-activated slag. The later was developed since 1956 in the former USSR (now Ukraine) by G.V. Glukhovsky. Alkali-activation, which is generally performed with corrosive chemicals (see below User-friendly), is used for the making of concretes exclusively. The alkali-activated materials are not manufactured separately and not sold to third parties as commercial cements. On the opposite, geopolymer technology was from the start aimed at manufacturing binders and cements for various types of applications.

A video stresses the major differences between alkali-activated materials/alkali-activated construction materials and geopolymers, go to  “Why Alkali-Activated Materials are NOT Geopolymers?“

For detailed information on Fly Ash based Geopolymer Cements and Concretes see in the Library the Technical paper #22 at GEOASH: fly ash-based geopolymer cements as well as the recently updated book Geopolymer Chemistry & Applications, Chapters 12, 24 and 25, and the results of the European Research project GEOASH in the next section. You may also go to the Geopolymer Library and download several papers, for example #21 Geopolymer cement review 2013, #22 GEOASH, #23 GP-AIRPORT.

In this section we are developing:
a) The recent industrial development of geopolymer concrete (100,000 tonnes and +)
b) The User-friendly geopolymer cement concept.

100,000 tonnes of Geopolymer Concrete for Airport + Eco-building

Brisbane West Wellcamp Airport (BWWA), Toowoomba, Queensland, is Australia’s first greenfield public airport to be built in 48 years. BWWA became fully operational with commercial flights operated by Qantas Link in November 2014. See our News dated of October 14, 2014, 70,000 tonnes Geopolymer Concrete for airport.

This project marks a very significant milestone in engineering – the world’s largest geopolymer concrete project. BWWA was built with approximately 40,000 m³ (100,000 tonnes) of geopolymer concrete making it the largest application of this new class of concrete in the world. The geopolymer concrete developed by the company Wagners, known as Earth Friendly Concrete (EFC), was found to be well suited for this construction method due to its high flexural tensile strength, low shrinkage and workability characteristics. Heavy duty geopolymer concrete, 435 mm thick, used for the turning node, apron and taxiway aircraft pavements, welcomes a heavy 747 cargo for regular air traffic between Toowoomba-Wellcamp BWWA airport and Hong Kong. For technical details read the paper by Glasby et al. (2015), EFC Geopolymer Concrete Aircraft Pavements at Brisbane West Wellcamp Airport, in our Library, Technical paper #23 GP-AIRPORT. Technical Paper on Geopolymer Aircraft Pavement.

Prof. Joseph Davidovits’ visit to the Toowoomba-Wellcamp-Airport.

On October 3, 2015, Joseph and Ralph Davidovits flew from Sydney Airport to Toowoomba-Wellcamp-Airport, for a visit to the company Wagners.

Prof. Joseph Davidovits’ visit to the Global Change Institute, Brisbane, Queensland, Australia.

On October 7, 2015, Joseph and Ralph Davidovits drove with Tom Glasby and Russell Genrich, company Wagners, from Toowoomba to Brisbane. Our News dated December 10, 2013, was titled World’s first public building with structural Geopolymer Concrete. It introduced the world’s first building to successfully use geopolymer concrete for structural purposes, the Global Change Institute, University of Queensland, Brisbane, Queensland, Australia. The 4 story high building, for general public use, comprises 3 suspended geopolymer concrete floors involving 33 precast panels. They are made from slag/fly ash-based geopolymer concrete coined Earth Friendly Concrete (EFC), a Wagners brand name for their commercial form of geopolymer concrete.

Mass Production of Geopolymer Cement

At the Geopolymer Camp 2009 at Saint-Quentin, France, Prof. Joseph Davidovits presented a keynote on “Practical Problems on Mass Produced Geopolymer Cement”. What are the key issues and what are the dead ends? What to do to make a cement that reduces the CO₂ emission by 60 up to 80%?

J. Davidovits’ Keynotes at Geopolymer Camp 2010, 2011, 2012, 2013, 2014 and 2015 contain additional information. Go to Keynotes of the Geopolymer Camp.

In the recently updated book Geopolymer Chemistry & Applications several chapters are dedicated to geopolymer , metakaolin-based, rock-based and fly ash-based cements and concretes, see in Chapters 8, 9, 10, 11, 12, 24 and 25. You may also go to the Geopolymer Library and download several papers.

If we compare in a microscope the structure of mortar made of regular cement with another sample made of geopolymer, we notice that the regular cement is a coarse stacking of grains of matter. This causes cracks and weaknesses. On the opposite, geopolymer cement (in black) is smooth and homogeneous. This provides, in fact, superior properties.

User-friendly geopolymer cements

Although geopolymerization does not rely on toxic organic solvents but only on water, it needs chemical ingredients that may be dangerous and therefore requires some safety procedures. Material Safety rules classify the alkaline products in two categories:

• corrosive products
• irritant products

The two classes are recognizable through their respective logos displayed below.

The Table lists some alkaline chemicals and their corresponding safety label. The corrosive products must be handled with gloves, glasses and masks. They are User-hostile and cannot be implemented in mass applications without the appropriate safety procedures. In the second category one finds Portland cement or hydrated lime, typical mass products. Geopolymeric mixes belonging to this class may also be termed as User-friendly.

When, in 1983 at the Central Laboratory of the American company Lone Star Industries, we started the research on geopolymer cements (Pyrament cement), we decided to select alkaline conditions that are User-friendly. (Na,K,Ca)-Poly(sialate-siloxo) and K-Poly(sialate) products (resins, binders and cements) have starting molar ratio SiO₂:M₂O ranging from 1.45 to 1.85. Unfortunately, this is not followed by other scientists and technicians involved in the development of so-called alkali-activated-cements, especially those based on fly ashes, with molar ratio in average below 1.0. Looking only at low-costs consideration, not at safety and User-friendly issues, they propose systems based on pure NaOH (8M or 12M). For example in a “State of the Art” on alkali-activated fly-ash cements, wrongly named geopolymer technology, published in 2007, several scientists claimed that the pure NaOH system should be considered as the reference for fly-ash-based cements (see: Duxson P., Fernandez-Jimenez A., Provis J.L., Lukey G.C., Palomo A. and van Deventer J.S.J., Geopolymer technology: the current state of the art, J. Mater. Sci., 42, 2917-2933, 2007). These are User-hostile conditions for the ordinary labor force employed in the field.

Finally, companies refuse to support the liability and pay high insurance fees based on such out-of-date processes. Indeed, laws, regulations, and state directives push to enforce for more health protections and security protocols for workers’ safety. Further details on fly-ash-based geopolymer cement in the page GEOASH, a project aimed to develop a real industrial process driven by these constraints.

Prof. Joseph Davidovits presents the road map for the next couple of years on geopolymer science innovation and research, at the 2^nd International Congress on Ceramics, Verona, Italy, July 4th, 2008.

There is a great need for innovation and therefore further research must be carried out. We have listed below the topics that deserve further involvement in the field of chemistry, physical-chemistry, materials science, and others. These needs are outlined in Davidovits’ book Geopolymer Chemistry & Applications, generally at the end of the chapter dedicated to the topic, and are given in the list.

We hope that this initiative will minimize the number of scientific papers and conference communications that are simply re-inventing the wheel, i.e. replicate studies and research already performed by others, sometimes several decades ago, and outlined in the reference book Geopolymer Chemistry & Applications.

The GeopolymerCamp is the opportunity to prepare the new edition of the book Geopolymer Chemistry & Applications. Indeed, the Geopolymer Institute wishes to publish every year a new revised edition with the most up to date information. During this session, participants will propose subjects or issues that are worthwhile to be edited or added, and the assembly will discuss about it. Prepare your arguments if you want to see your last research, data, applications be added to this reference book.

Research topics:

Chapter 2: Polymeric character of geopolymers: geopolymeric micelle
“Further research is needed to provide scientific tools for the determination of several physical parameters such as overall dimension and molecular weight.”

Let physicochemical research institutions confirm covalent bonding system. Determine the molecular weight of the geopolymer micelle, a nanosized particulate detected by W. Kriven in 2003.

Chapter 5: Poly(siloxonate), soluble silicate (waterglass)
“The standard industrial silicates are mixtures of several silicate species (…) Any changes in the industrial fabrication parameters will strongly affect the nominal mixture composition and the geopolymeric properties of the soluble silicates obtained with these glasses (…) Nevertheless, researchers in geopolymer science should always keep in mind these data when developing tailored industrial geopolymer applications (…) Further research on this important topic will probably provide additional 3-D structures connected with the solid rings and polygons disclosed in Figure 5.9. (…) Further research is needed on this crucial technology.”

Let modify and master the manufacture process in order to get uniformity and quality control on the molecular sizes of Na-poly(siloxonate), K-poly(siloxonate) (soluble silicate).

Chapter 8: Metakaolin MK-750-based geopolymer
“In general, (Na,K)–poly(sialate-siloxo) is not made of single polymeric macromolecules but consists of a mixture, a solid solution, of at least two well defined geopolymers with different Si:Al ratios. The standardized methods of investigation, like ²⁹Si and ²⁷Al NMR spectroscopy, are not sophisticated enough for the detection and separation of these different macromolecules. Future research is necessary. (…) The identification of Al-O-Al bonding in geopolymers has been confirmed by ¹⁷O MAS-NMR spectroscopy as the one displayed in Figure 8.24… The effect seems to diminish with the increase of the Si:Al ratio, when oligo-siloxonate molecules, Q₀ , Q₁ and Q₂ types are added to the geopolymeric reactant mixture. Further research is needed.”

Chapter 9: Calcium-based geopolymer
“There is production of two geopolymers: hydrated gehlenite and (Na,K)–poly(sialate-siloxo), and in addition calcium di-siloxonate hydrate (CSH cement type). Further research is needed on this very interesting topic of ancient Roman technology. (…) We could also assume that, in the hydrated state, our geopolymeric structures are more flexible than the rigid anhydrous chains. Their molecular arrangement might comply with the replacement of K⁺ with Ca⁺⁺. Further research is needed to clarify this important issue.”

Chapter 10: Rock-based geopolymer
“The extrapolation from the solid solution structures set forth in Chapter 9 would probably focus on the Ca-siloxonate-hydrate, and its resonance at -78 ppm for Q₁ structure in the ²⁹Si spectrum of Figure 10.5. However, in addition to the dimer Ca-di-siloxonate hydrate molecule, one could get higher oligomers: trimer, tetramer, pentamer, hexamer, with cyclic structures similar to those depicted for soluble silicates in Figure 5.13 of Chapter 5 as well as in Figure 2.8 of Chapter 2. Further research is needed.”

Chapter 11: Silica-based geopolymer
“The geopolymer composite has a high potential for fire-heat resistant coatings as well as corrosion resistant paint for steel. With tailored ceramic fillers one obtains heat stable materials with remarkable heat resistance. Further research is needed. (…) These results highlight the need for caution during the use and disposal of these manufactured nanomaterials to prevent unintended environmental impacts, as well as the importance of further research on tailored formulations aimed at preventing any risk.”

Chapter 12: Fly ash-based geopolymer
“Overall, the geopolymer matrix gives a Si:Al molar ratio ranging from 1.56–2.14 corresponding to a poly(sialate-siloxo) with inclusions of siloxonate-hydrate molecules consisting of higher oligomers: trimer, tetramer, pentamer, hexamer, with cyclic structures similar to those depicted for soluble silicates in Figure 5.13 of Chapter 5 as well as in Figure 2.8 of Chapter 2. Further research is needed. (…) Gasifier slag consists of four main components: silica, alumina, iron oxide and calcium oxide, mainly added as a flux in the gasification process. The gasifier slag composition is similar to that of iron blast-furnace slag (Sullivan and Hill, 2001). In other words, a possible shortage of iron blast-furnace slag would be easily compensated by the production of gasifier slag, opening new perspectives for the industrial implementation of geopolymers issuing from coal combustion in electrical power plants. Further research is needed.”

Chapter 13: Phosphate-based geopolymer
“Several laboratories are working on the inclusion of PO₄ units into sialate and sialate-siloxo sequences. Data have not been published, so far. Further research is needed on these materials that show promising potential applications.”

Chapter 14: Organic-mineral geopolymer
“Further research is needed in order to take advantage of the chemical compatibility of poly-organo-siloxane and mineral geopolymers. (…) Further research is needed on the geopolymerization mechanism in acid medium. (…) The previous examples show the potentiality of organo-mineral geopolymer compounds. Further research is needed.”

Chapter 17: Long-term durability
“As for technological applications of geopolymeric materials in waste management, any risk assessment must contain input from geological and geochemical analogues. The problem is the very low amount of available data on this topic. Further research is needed.

Chapter 21: Geopolymer-fiber composites
“In this Chapter, the best results involved the use of carbon or SiC fibers that are more expensive than E-glass. Future research will therefore take advantage of the geopolymeric systems outlined in Chapter 13 with phosphate based acidic matrix. This chemistry is not as aggressive to E-glass as the alkali driven poly(sialate) medium.”

The introduction of composites on a large scale in aircraft manufacture by Boeing and Airbus highlights the demand for fire- as well as heat-resistant geopolymer matrices.

Chapter 23: Geopolymer in ceramic processing
Introduce and develop LTGS for the production of low-cost building materials in developing countries with user-friendly geopolymeric ingredients.

Chapter 24: The manufacture of geopolymer cements
“We have learned in Chapter 19 that these dry mixes based on dry NaOH/KOH are corrosive in nature and may not be used (see in section 19.2, The need for user-friendly systems ). Research and development should therefore focus on innovative solutions involving the manufacture of ready to use, user-friendly, geopolymeric precursors. (…) Further research and development is needed on this very important technology.”

The major obstacle to the mass application of geopolymer cements comes from the chemical industry that is unable to manufacture the estimated 250-300 millions tonnes / year of alkali-silicates poly(siloxonates) needed for mass production of geopolymer cements, world-wide (presently ca. 15 millions tonnes / year). One must invent new methods of manufacture for poly(siloxonate) glasses, from geological raw-materials rich in K₂O and Na₂O, as in the European Research project GEOCISTEM (Brite-Euram 1994-1997).

Chapter 25: Geopolymer concrete
“When one adds together the properties described in this Chapter 25, and the chemical and physical parameters of geopolymer cements outlined in previous chapters, it becomes evident that geopolymer concrete is better than Portland cement concrete. Yet, further research is needed to apply and generalize to all geopolymer concrete types the results obtained by B.V. Rangan and his team.”