published January 2020: DOI: 10.13140/RG.2.2.25792.89608/2

published May 2019: DOI: 10.13140/RG.2.2.18109.10727/1

published November 2018: DOI: 10.13140/RG.2.2.34337.25441

Why Alkali-activated-materials AAM are not Geopolymers

Script of the Video series available
at the Geopolymer Institute, Why-AAM-are not GP and on YouTube.

Many scientists and civil engineers are mistaking alkali activation for geopolymers, fueling confusion, using them as synonyms without understanding what they really are.
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. They 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.

In my four keynotes at the Geopolymer Camp (2014-2017), I 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 videos are titled: Why Alkali- Activated Materials are NOT Geopolymers. You will finally understand why there are two different systems.

Click here to see how to download paper nr 25 Why-AAM.pdf.

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.

Last year (October 14, 2014), our News was titled 70,000 tonnes Geopolymer Concrete for airport; it presented company Wagners’ newly developed geopolymer concrete EFC in the construction of the Brisbane West Wellcamp Airport (BWWA), Toowoomba, Australia, which became fully operational with commercial flights operated by Qantas Link in November 2014. 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, 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, was used for the turning node, apron and taxiway aircraft pavements, and cast in place with the slip form paving machine displayed below.

EFC Geopolymer Concrete Aircraft Pavements at Brisbane West Wellcamp Airport.

by Tom Glasby, John Day, Russell Genrich and James Aldred.

Paper presented at Concrete 2015 Conference, Melbourne Australia 2015.

CONTENT
1. Introduction
2. Project Outline
3. Geopolymer Concrete Mix
4. Geopolymer Concrete Production and Supply
5. Geopolymer Concrete Pavement Construction
6. Commercialisation of Geopolymer Concrete
7. Conclusion
References

Click here to see how to download paper nr 23 GP-AIRPORT.

Development of room temperature hardening for fly ash-based geopolymer cements and concretes.

When compared with alkali-activated, heat-cured conventional methods, the slag/fly ash-based geopolymer cement technologies, which harden at ambient temperature, provide better properties: higher strength, safer long-term durability and lower leachates.

CONTENT
1. Introduction
2. Methods
2.1 Conventional Method: Alkali-Activation, Dissolution And Zeolite Formation: User-Hostile
2.2 Geopolymeric Method: Room Temperature Hardening, Polycondensation, User-Friendly.
3. Results And Discussion
3.1 Compressive Strength
3.2 X-Ray Diffraction
3.3 Leaching Properties
3.4 (Ca,K)-Based Geopolymer Matrix: Composition And Structure
References

Click here to see how to download paper nr 22.

Prof. Joseph DAVIDOVITS

CONTENT

1. Introduction
2. Portland cement chemistry vs Geopolymer cement chemistry
   2.1 Alkali-activated materials vs Geopolymer cements.
   2.2 User-friendly alkaline-reagents
3. Geopolymer cement categories
   3.1 Slag-based geopolymer cement
   3.2 Rock-based geopolymer cement
   3.3 Fly ash-based geopolymer cements
   3.4 Ferro-sialate-based geopolymer cement
4. CO2 emissions during manufacture
   4.1 CO2 emission during manufacture of Portland cement clinker
   4.2 Geopolymer Cements Energy Needs and CO2 emissions
      4.2.1 Rock-based Geopolymer cement manufacture involves:
          4.2.1.1 Energy needs
          4.2.1.2 CO2 emissions during manufacture
      4.2.2 Fly ash-based cements Class F fly ashes
5. Properties for Rock-based geopolymer cement (Ca,K)-poly(sialate-disiloxo)
6. The need for standards
References

Click here to see how to download paper nr 21.

Solid-Phase Synthesis of a Mineral Blockpolymer by Low Temperature Polycondensation

of Alumino-Silicate Polymers: Na-poly(sialate) or Na-PS and Characteristics .

Joseph DAVIDOVITS

INTRODUCTION

The work exposed here comes from an attempt to transfer our knowledge of organic polymers and the technologies associated with it to the yet unknown, or hardly known field of the synthesis and transformation of inorganic polymers, in order to develop new materials and new industrial processes. It is a matter of fact that inorganic materials like glass, ceramics, bricks, concrete, and most natural rocks by far outclass organic polymers with respect to their resistance to high temperature. This study provides an answer to the following question: Could we take mineral materials such as clay, kaolinite, that is to say aluminosilicate polymers, and transform them using the extreme low-temperature polymerisation technology of organic polymers ?”.The answer is : yes, we can. The resulting products have similar characteristics to natural rock‑forming minerals, such as zeolites, feldspathoids and feldspars. These different minerals are usually called silicates or aluminosilicates in the same way as kaolinite, clays, micas, mullite, andalusite, spinel, etc. that is in brief all the minerals whose empirical formula contains Si, AI, O, and any other elements such as H, Na, K, Ca, Mg, etc. For the development of our knowledge and for a better understanding of the mechanism of this new synthesis of inorganic polymers, we felt we had to introduce a more precise terminology.

Click here to see how to download paper nr 20.

For thousands of years sculpture has been invented to be seen in daylight. Today, artificial light opens the door to a new approach, all the more so since the advent of new materials, upsetting our concepts in many fields. To traditional sculpture I propose to add decorative sculpture for indoors in which a stage setting by light becomes an integral part of the work. Well-gauged lighting enhances the finesse of the feelings expressed. Adjusted shade conveys the poetic value of the « unspoken ».

DRAMATIZED Sculpture may follow a similar course to that of recorded music during this century, from phonographs to C.D.. This paper is illustrated with several photos in color.

Click here to see how to download paper nr 19.

Published in The Indian Concrete Journal, April 2014, Vol. 88, Issue 4, pp. 41-48, 50-59.

Professor Vijay Rangan is Australia Mr. Concrete. He presents here a review on the extensive studies conducted on fly ash-based geopolymer concrete. Salient factors that influence the properties of the geopolymer concrete in the fresh and hardened states are identified. Test data of various short-term and long-term properties of the geopolymer concrete are then presented. The paper describes the results of the tests conducted on large-scale reinforced geopolymer concrete members and illustrates the application of the geopolymer concrete in the construction industry. Some recent applications of geopolymer concrete in the precast construction and the economic merits of the geopolymer concrete are also included.

It is the complement of previous Research Reports GC1 and GC2 that covered the development, the mixture proportions, the short-term properties, and the long-term properties of low-calcium fly ash-based geopolymer concrete, see paper #17 .

The study demonstrated that the design provisions contained in the Australian Standard for Concrete Structures AS3600 and the American Concrete Institute Building Code ACI318-02 are applicable to reinforced Fly ash-based geopolymer concrete columns.

Click here to see how you can download paper number 18.

From 2001, we have conducted some important research on the development, manufacture, behaviour, and applications of Low-Calcium Fly Ash-Based Geopolymer Concrete. This concrete uses no Portland cement; instead, we use the low-calcium fly ash from a local coal burning power station as a source material to make the binder necessary to manufacture concrete. Concrete usage around the globe is second only to water. An important ingredient in the conventional concrete is the Portland cement. The production of one ton of cement emits approximately one ton of carbon dioxide to the atmosphere. Moreover, cement production is not only highly energy-intensive, next to steel and aluminium, but also consumes significant amount of natural resources. In order to meet infrastructure developments, the usage of concrete is on the increase. Do we build additional cement plants to meet this increase in demand for concrete, or find alternative binders to make concrete?

In this work, low-calcium (ASTM Class F) fly ash-based geopolymer is used as the binder, instead of Portland or other hydraulic cement paste, to produce concrete. The fly ash-based geopolymer paste binds the loose coarse aggregates, fine aggregates and other un-reacted materials together to form the geopolymer concrete, with or without the presence of admixtures. The manufacture of geopolymer concrete is carried out using the usual concrete technology methods. As in the case of OPC concrete, the aggregates occupy about 75-80 % by mass, in geopolymer concrete. The silicon and the aluminium in the low-calcium (ASTM Class F) fly ash react with an alkaline liquid that is a combination of sodium silicate and sodium hydroxide solutions to form the geopolymer paste that binds the aggregates and other unreacted materials.

This paper contains 2 reports. The first Report GC1 (curtin-flyash-GP-concrete-report.pdf) describes the mixes and the short term properties. The second Report GC2 (curtin_flyash_GC-2.pdf) provides the long term properties. See the conclusions below.

Click here to see how you can download paper number 17.

Based on the test results, the following conclusions are drawn:
1. There is no substantial gain in the compressive strength of heat-cured fly ash- based geopolymer concrete with age.
2. Fly ash-based geopolymer concrete cured in the laboratory ambient conditions gains compressive strength with age.
3. Heat-cured fly ash-based geopolymer concrete undergoes low creep.
4. The creep coefficient, defined as the ratio of creep strain-to-instantaneous strain, after one year for heat-cured geopolymer concrete with compressive strength of 40, 47 and 57 MPa is around 0.6 to 0.7; for geopolymer concrete with compressive strength of 67 MPa this value is around 0.4 to 0.5.
5. The heat-cured fly ash-based geopolymer concrete undergoes very little drying shrinkage in the order of about 100 micro strains after one year. This value is significantly smaller than the range of values of 500 to 800 micro strain for Portland cement concrete.
6. The drying shrinkage strain of ambient-cured specimens is in the order of 1500 microstrains after three months. This value is many folds larger than that of heat- cured specimens, and the most part of that occurs during the first few weeks.
7. The test results demonstrate that heat-cured fly ash-based geopolymer concrete has an excellent resistance to sulfate attack.
8. Exposure to sulfuric acid solution damages the surface of heat-cured geopolymer concrete test specimens and causes a mass loss of about 3% after one year of exposure. The severity of the damage depends on the acid concentration.
9. The sulfuric acid attack also causes degradation in the compressive strength of heat-cured geopolymer concrete; the extent of degradation depends on the concentration of the acid solution and the period of exposure. However, the sulfuric acid resistance of heat-cured geopolymer concrete is significantly better than that of Portland cement concrete as reported in earlier studies.

Invited Paper, Geopolymer 2002 International Conference, October 28-29, Melbourne, Australia

Environmentally driven geopolymer applications are based on the implementation of (K,Ca)-Poly(sialate-siloxo) / (K,Ca)-Poly(sialate-disiloxo) cements. In industrialized countries (Western countries) emphasis is put on toxic waste (heavy metals) and radioactive waste safe containment. On the opposite, in emerging countries, the applications relate to sustainable development, essentially geopolymeric cements with very low CO₂ emission. Both fields of application are strongly dependent on politically driven decisions.

Click here to see how you can download paper number 16.

Invited Paper, Geopolymer 2002 International Conference, October 28-29, Melbourne, Australia

The presentation included 30 slides describing following geopolymer applications developed since 1972 in France, Europe and USA. The Geopolymer chemistry concept was invented in 1979 with the creation of a non-for profit scientific organization, the Institut de Recherche sur les Géopolymères (Geopolymer Institute); Fire resistant wood panel; Insulated panels and walls. Decorative stone artifacts; Foamed (expanded) geopolymer panels for thermal insulation; Low-tech building materials; Energy low ceramic tiles; Refractory items; Thermal shock refractory; Aluminum foundry application; Geopolymer cement and concrete; Fire resistant and fire proof composite for infrastructures repair and strengthening; Fireproof high-tech applications, aircraft interior, automobile; High-tech resin systems. The applications are based on 30 patents filed and issued in several countries. Several patents are now in the public domain, but others are still valid. The applications show genuine geopolymer products having brilliantly withstood 25 years of use and that are continuously commercialized.

Click here to see how you can download paper number 15.

In English:

After a concise presentation of the chemical principles governing the LTGS geopolymeric cross-linking with the main mineralogical components of soils, earths and clays, the authors present their experiments for a rational use of lateritic materials. Several tests were carried out with African soils of various origins but the standardization of the processes was made by using a material extracted in Provence, France.
The geopolymerisation techniques make it possible to obtain building materials meeting all the architectural needs: water stable bricks, hardened at room temperature, ceramic bricks with maximum heating from 85°C to 450°C (solar and simple wood fire), cement and hydraulic mortar from laterites, wall and floor coating, and roof.

En Français:

Après une présentation succincte des principes chimiques régissant la réticulation géopolymérique (LTGS) des principaux constituants minéralogiques des sols, terres et argiles, les auteurs, présentent leur expérience quant à l’utilisation rationnelle des matériaux de type latéritique. Les différents essais ont porté sur des terres africaines d’origine diverses mais la standardisation de plusieurs procédés a été faite en utilisant un matériau extrait en Provence, en France, sur le site d’Ollière.
Les techniques de géopolymérisation permettent d’obtenir des matériaux de construction couvrant tous les besoins architecturaux: briques stables à l’eau, durcies à température ambiante, briques céramiques par cuisson de 85°C à 450°C maximum (solaire et simple feu de bois), ciment et mortier hydraulique à partir de latérites, revêtements de sols et de mur, et toiture.

Click here to see how you can download paper number 14.

(1) B.P.S. Engineering GmbH
(2) WISMUT GmbH
(3) Cordi-Géopolymère SA

published in the Géopolymère ‘99 Proceedings, 2nd International Conference on Geopolymers

Sludges containing radionuclides, toxic heavy metals and hydro-carbons can be solidified by geopolymer with excellent long-term structural, chemical and microbial stability, satisfying high standards of contaminant retention. The novel technology gives a monolithic product which can be easily handled, stored and monitored. It requires only simple mixing and moulding technology known from conventional solidification methods.

Extensive laboratory investigation has been carried out to demonstrate the performance of the novel solidification method under adverse stress conditions. In particular, the sludges of a treatment facility for uranium mining effluents and sludges from a settling pond, contaminated organically, radioactively and by heavy metals, have been treated. An optimized two-step technology, known as geopolymer, was successfully adapted to the specific characteristics of these sludges. Moreover, the geopolymer process has been shown to deliver excellent results for radioactive and arsenic-loaded sludges from municipal drinking water purification plants that are sensitive with respect to public risk perception and regulatory policy.

Pilot-scale experiments that show the method’s maturity for industrial use and to provide realistic material and operation cost estimates were done for the uranium mine sludges. Several tons were solidified in WISMUT’s Schlema-Alberoda water treatment plant in 1998. Our results clearly show that geopolymer solidification is a prime candidate to fill cost-efficiently the gap between conventional concrete technology and vitrification methods. Due to the reduced effort to prepare, operate and close the landfill, solidification by geopolymer leads to approximately the same unit cost as by conventional portland cement, but provides in most aspects the performance of vitrification.

The paper is divided into two parts. Part I describes in detail the basic principles of geopolymer and the laboratory investigations carried out to develop a viable solidification technology. After briefly introducing the basic principles of the Geopolytec® process and comparing it to conventional solidification methods, our paper shows promising results that were obtained for the long-term stability and contaminant retention of under several testing procedures. Subsequently, the experience from the pilot-scale experiment in the water treatment facility of WISMUT is presented. It shows that the Geopolytec® process is now mature for industrial application.

Part II is devoted to a pilot-scale experiment in which about 10 tons of radioactive and toxic sludges were solidified by the Geopolytec® process.

Finally, the prospects and market potential for the solidification of sludges by geopolymer are discussed, and an outlook to future activities is given.

Click here to see how you can download paper number 13.

Spectacular technological progress has been made in the last few years through the development of new materials such as ‘geopolymers’, and new techniques, such as ‘sol-gel’. New state-of-the-art materials designed with the help of geopolymerisation reactions are opening up new applications and procedures and transforming ideas that have been taken for granted in inorganic chemistry. High temperature techniques are no longer necessary to obtain materials which are ceramic-like in their structures and properties. These materials can polycondense just like organic polymers, at temperatures lower than 100°C. Geopolymerization involves the chemical reaction of alumino-silicate oxides (Al3+ in IV-fold coordination) with alkali polysilicates yielding polymeric Si-O-Al bonds; the amorphous to semi-crystalline three dimensional silico-aluminate structures are of the Poly(sialate) type(- Si-O-Al-O -), the Poly(sialate-siloxo) type (- Si-O-Al-O-Si-O -), the Poly(sialate-disiloxo) type (- Si-O-Al-O-Si-O-Si-O -).

This new generation of materials, whether used pure, with fillers or reinforced, is already finding applications in all fields of industry. Some examples:

• pure: for storing toxic chemical or radioactive waste, etc.
• filled: for the manufacture of special concretes, molds for molding thermoplastics, etc.
• reinforced: for the manufacture of molds, tooling, in aluminum alloy foundries and metallurgy, etc.

These applications are to be found in the automobile and aerospace industries, non ferrous foundries and metallurgy, civil engineering, plastics industries, etc.

Click here to see how you can download paper number 12.

Cette brochure grand public présente les activités et les différents produits en géopolymère.

L’industrialisation des matériaux nouveaux issus de la science des géopolymères fait maintenant partie des priorités technologiques de l’Union Européenne.
Hier, l’accent portait sur les performances techniques et le caractère “high-tech” des innovations.
Aujourd’hui, les développements présents et futurs ont comme priorité la mise en place des moyens de production industrielle à grande échelle, adaptés à la nouvelle Économie Globale.

Click here to see how you can download paper number 11.

This paper has been adapted from an article written for the general audience by two independent French journalists. It outlines the story of geopolymer and his inventor Prof. Joseph Davidovits .

Click here to see how you can download paper number 10.

Geopolymers of the Poly(sialate-disiloxo) type (- Si-O-Al-Si-O-Si-O -), very-low viscosity inorganic resins, harden like thermosetting organic resins, but have use-temperature range up to 1000°C (1830°F). High-temperature techniques are no longer necessary to obtain materials which are ceramic-like in their properties. Geopolymers provide faithful reproduction of mold or die surface and allow for precision and fineness. Geopolymer composite-tooling and geopolymer castable-tooling offer direct replication, on-site construction capabilities and very short cure-cycle. They enable product designers and tool makers to envisage the use of ceramic type materials with the same facility as organic polymers. Geopolymer composite and castable tooling have been fabricated and are in use, processing APC-2 thermoplastic materials as well as PMR-15 polyimides.

Click here to see how you can download paper number 9.

Geopolymer cement, high-alkali (K-Ca)-Poly(sialate-siloxo) cement, results from an inorganic polycondensation reaction, a so-called geopolymerisation yielding three dimensional zeolitic frameworks. High-tech Geopolymer K-Poly(sialate-siloxo) binders, whether used pure, with fillers or reinforced, are already finding applications in all fields of industry. These applications are to be found in the automobile and aeronautic industries, non-ferrous foundries and metallurgy, civil engineering, plastics industries, etc. Geopolymer cement hardens rapidly at room temperature and provides compressive strengths in the range of 20 MPa, after only 4 hours at 20°C, when tested in accordance with the standards applied to hydraulic binder mortars. The final 28-day compression strength is in the range of 70-100 MPa. The behaviour of geopolymeric cements is similar to that of zeolites and feldspathoids; they immobilize hazardous materials within the geopolymeric matrix, and act as a binder to convert semi-solid wastes into adhesive solids. Their unique properties which include high early strength, low shrinkage, freeze-thaw resistance, sulphate resistance and corrosion resistance, make them ideal for long term containment in surface disposal facilities. These high-alkali cements do not generate any Alkali-Aggregate-Reaction. Preliminary study involving 27 Al and 29 Si MASNMR spectroscopy and the proposed structural model, reveal that geopolymeric cements are the synthetic analogues of natural tecto-alumino-silicates.

Click here to see how you can download paper number 8.