Journal de génie civil et environnemental

Synthesis of Alkali Activated Geopolymer Cement from Clay

Abstract

Sanjaya Dahal

The term "geopolymer" was created and applied by Davidovits, a French scientist, in 1979 to represent a kind of inorganic polymer with SiO₄ and A₁O₄ tetrahedral being the structural units. In general, geopolymers as a class of inorganic polymer are formed by reaction between an alkaline solution [e.g., sodium hydroxide and sodium silicate] and an aluminosilicate sources such as metakaolin, fly ash, and slag. Nowadays, geopolymer studies are receiving commendably increasing attention because they may be used as a viable economical alternative to organic polymers and inorganic cements in diverse applications, such as military, aircraft high-tech ceramics thermal insulating foams fire-proof building materials protective coatings refractory adhesives and hybrid inorganicorganic composites. This interest is due to their exceptionally high thermal and chemical stability, excellent mechanical strength, adhesive behavior and long-term durability. In addition, early researcher have demonstrated that geopolymers are cheap to produce and can be made from a great number of minerals and industrial by-products, including pozzolana, natural aluminosilicate minerals, metakaolin fly ash granulated blast furnace slag fly ash and kaolinite mixture fly ash and metakaolin mixture red mud and metakaolin mixture and red mud and fly ash mixture. Moreover, they are environmentally friendly materials from the point of view of reducing green house effects caused by CO₂ emission from the manufacturing of Portland cement.