Geopolymer Institute

Geopolymers are chains or networks of mineral molecules linked with co-valent bonds. They comprise following molecular units (or chemical groups):
-Si-O-Si-O- siloxo, poly(siloxo)
-Si-O-Al-O- sialate, poly(sialate)
-Si-O-Al-O-Si-O- sialate-siloxo, poly(sialate-siloxo)
-Si-O-Al-O-Si-O-Si-O- sialate-disiloxo, poly(sialate-disiloxo)
-P-O-P-O- phosphate, poly(phosphate)
-P-O-Si-O-P-O- phospho-siloxo, poly(phospho-siloxo)
-P-O-Si-O-Al-O-P-O- phospho-sialate, poly(phospho-sialate)
-(R)-Si-O-Si-O-(R) organo-siloxo, poly-silicone
Geopolymers are presently developed and applied [...]

In 1937 W. L. Bragg published a method for classifying all kinds of silicates and their crystal structures based on the concept of the ionic theory by L. Pauling. The fundamental unit is a tetrahedral complex consisting of a small cation such as Si4+, or Al3+ in tetrahedral coordination with four oxygens (Pauling’s first rule). [...]

X-rays diffraction spectra of hardened geopolymeric materials (resins and cements) do not supply accurate information (amorphous structure). High-resolution MAS-NMR (Nuclear Magnetic Resonance) spectroscopy of 29Si and 27Al is a very powerful tool that provides useful structural data.
For more updated information, see in Davidovits’ book, Geopolymer Chemistry & Applications, the Chapter 4. You may also [...]

Geopolymerization forms aluminosilicate frameworks which are similar to those of rock-forming minerals. Yet there are major differences. At low temperature, generally below 300°C, geopolymers contain hydroxyl groups -OH as well as bounded water (so-called zeolitic water), and the structures shown in the figure below must be edited accordingly, with the exception of the sodalite framework. [...]

The atomic ratio Si:Al in the poly(sialate) structure determines the properties and application fields. A low ratio Si:Al (1,2,3) initiates a 3D-Network that is very rigid. A high ratio Si:Al, higher than 15, provides polymeric character to the geopolymeric material. One third of Davidovits’ book, GEOPOLYMER Chemistry & Applications, is dedicated to applications. See the [...]

Technical Data Sheet for Geopolymeric cement type (Potassium, Calcium) – Poly(sialate-siloxo) / (K,Ca) – (Si-O-Al-O-Si-O-), Si:Al=2:1
Further details in Davidovits’ book, GEOPOLYMER Chemistry & Applications, Part III, Properties, Chapters 15 to 18, GEOCISTEM , GLOBAL WARMING, and also previous papers in the Geopolymer Library.
Tested on standard sand mortar prisms:

setting: 10 hours at -20°C to 7-60 minutes [...]

Applications with geopolymer cements and concretes are described in the section Geopolymer Cement with special emphasis on the introduction of user-friendly systems. It is striking to notice that Geopolymer cements manufacture emits 80 to 90% less CO2 (greenhouse effect gas) than Portland Cement. See in GLOBAL WARMING. They are perfect examples of Green Chemistry and [...]

Left: hardening of Portland cement (P.C.) through simple hydration of Calcium Silicate into Calcium Di-Silicate hydrate and lime Ca(OH)2.
Right: hardening (setting) of Geopolymer resin (GP) through poly-condensation of Potassium Oligo-(sialate-siloxo) into Potassium Poly(sialate-siloxo) cross linked network.

Geopolymeric binders, used either with rock aggregates to produce rock-concretes or with carbon fibers to produce non-flammable composites, have a variety of important industrial uses.
The same geosynthesis that produces geopolymeric rock-cements is used industrially for making binders for advanced composite materials and ceramics. Updated research is presented in Davidovits’ book, Geopolymer Chemistry & Applications, [...]

Prof. Joseph Davidovits presents the road map for the next couple of years on geopolymer science innovation and research, at the 2nd International Congress on Ceramics, Verona, Italy, July 4th, 2008. Watch the video on Vimeo.
There is a great need for innovation and therefore further research must be carried out. We have listed below the [...]