Contents • • • • • • • • • • • • • • • • • • • • • • • • • • • What is a geopolymer? [ ] In the 1950s, Viktor Glukovsky, of Kiev, USSR, developed concrete materials originally known under the names 'soil silicate concretes' and 'soil cements', but since the introduction of the geopolymer concept by, the terminology and definitions of 'geopolymer' have become more diverse and often conflicting. The examples below were taken from 2011 scientific publications, written by scientists with different backgrounds. Definitions of the term geopolymer For chemists '.Geopolymers consist of a polymeric Si–O–Al framework, similar to zeolites. The main difference to zeolite is geopolymers are amorphous instead of crystalline.

Type or paste a DOI name into the text box. Your browser will take you to a Web page (URL) associated with that DOI name. Send questions or comments to doi. Materials Science and Engineering A provides an international medium for the publication of theoretical and experimental studies related to the. Characterization of the development of microstructure and porosity of cement-based materials by numerical simulation and ESEM image analysis. Authors; Authors. The potential application of this simulated 3D microstructure on the transport properties being studied by applying a network permeability model. The capillary.

The microstructure of geopolymers on a nanometer scale observed by TEM comprises small aluminosilicate clusters with pores dispersed within a highly porous network. The clusters sizes are between 5 and 10 nanometers.' For geopolymer material chemists '.The reaction produces SiO 4 and AlO 4, tetrahedral frameworks linked by shared oxygens as poly(sialates) or poly(sialate–siloxo) or poly(sialate–disiloxo) depending on the SiO 2/Al 2O 3 ratio in the system. The connection of the tetrahedral frameworks is occurred via long-range covalent bonds. Thus, geopolymer structure is perceived as dense amorphous phase consisting of semi-crystalline 3-D alumino-silicate microstructure.'

For alkali-cement scientists '. Geopolymers are framework structures produced by condensation of tetrahedral aluminosilicate units, with alkali metal ions balancing the charge associated with tetrahedral Al. Conventionally, geopolymers are synthesized from a two-part mix, consisting of an alkaline solution (often soluble silicate) and solid aluminosilicate materials. Geopolymerization occurs at ambient or slightly elevated temperature, where the leaching of solid aluminosilicate raw materials in alkaline solutions leads to the transfer of leached species from the solid surfaces into a growing gel phase, followed by nucleation and condensation of the gel phase to form a solid binder.'

For geopolymer ceramic chemists:'Although geopolymer is generally X-ray amorphous if cured at standard pressures and temperatures, it will convert into crystalline ceramic phases like leucite or pollucite upon heating.' For ceramic scientists '.Geopolymers are a class of totally inorganic, alumino-silicate based ceramics that are charge balanced by group I oxides. Imsi Masterclips 250 Grams.

They are rigid gels, which are made under relatively ambient conditions of temperature and pressure into near-net dimension bodies, and which can subsequently be converted to crystalline or glass-ceramic materials.' Geopolymer synthesis [ ] Ionic coordination or covalent bonding? [ ] In 1937, W.

Bragg published a method for classifying all kinds of and their based on the concept of the ionic theory. The fundamental unit is a tetrahedral complex consisting of a small cation such as Si 4+, or Al 3+ in tetrahedral coordination with four oxygens (Pauling’s first rule).

Many textbooks explain the geometry of the SiO 4 4− tetrahedron and other mineral structures as determined by the relative sizes of the different ions. This ionic coordination representation is no longer adapted to the requirements of geopolymer chemistry that is governed by covalent bonding mechanisms. The differences between the ionic concept (coordination) and the covalent bonding are profound. The double tetrahedron structure (coordination) is sharing one oxygen anion O 2−, whereas in the Si-O-Si- molecular structure, the covalent bond is achieved through Si and O co-sharing only one electron. This results in stronger bond within the latter structure. The American mineralogist and geochemist G.