The term “geopolymer” was introduced by Davidovits in the 1970s. The prefix “geo” was selected to symbolize the constitutive relationship of the binders to geological materials, natural stone and/or minerals. Geopolymer is mineral polymers of inorganic polymer glasses with structure resembling natural zeolitic materials. Previously, geopolymer formation used source materials such as clay (e.g. kaolin and calcined kaolin) or industrial by-product (e.g. slag and fly ash). The precursor material plays an important role in the formation of geopolymer. The source material provides silicon (Si) and aluminum (Al) for reaction by an alkali activator solution. The Si and Al contents in the source materials dissolve in the alkaline activator solution and then polymerize to form a polymeric Si-O-Al-O framework which becomes the binder. Geopolymeric materials are attractive because of their excellent mechanical properties; durability and thermal stability can also be achieved. Owing to their low calcium content, they are more resistant to acid attack than materials based on Portland cement. In addition, they are of great interest because of the reduced energy requirement for their manufacture and the higher sustainability. Recently the search for alternative low cost and easily available materials led among others to Clay. Clay generally consists of a mixture of different clay minerals and associated minerals, which are strongly affected by the nature of the parent rocks. These materials are extensively distributed over the surface of the world and may show certain reactivity after a thermal activation process shows a great potential to be utilized in geopolymer technology. This article presents the potential of different types of clay as the source materials for geopolymerization reaction in terms of morphological properties. Moreover, the mechanical and microstructural properties of geopolymer made with various kinds of clay and its potential application are also presented.
Part of the book: Cement Based Materials
Description on rhetorical strategies modeling proposed by experts in the field of language provides clues on strategies used in research writing. However, the interpretation and analysis on the utilization of the rhetorical strategies models are limited to comparing the strategies used in articles grouped according to research disciplines such as biomedical, linguistics, and arts. In view of the constraint, this chapter focuses on the interpretations of rhetorical strategies modeling by analyzing the computer science research articles in a few categories. The first interpretation of analysis is on the articles with high and low citation index, followed by analysis on the articles grouped according to journal wise population and lastly analysis on articles written by non-native writers. The interpretation of the analysis suggested that the strategies proposed in the models are used differently by the writers of articles with high and low citations, writers of different journals, and non-native writers. The descriptions provided in this chapter account on the important strategies utilized by highly cited writers, specific journals, and non-native writers.