Composition and microstructure of fly ash geopolymer containing metakaolin

It is well known that kaolin contains a large amount of silica and alumina. When burnt at optimum temperature, metakaolin (MK) can be obtained and also used as raw material for making geopolymer. In Thailand, there are various sources of kaolin for use in ceramics industries. A study on the use of fly ash incorporating with MK to produce geopolymer so far was researched and developed by various researchers (Davidovits 1970, Davidovits 1999, Hardjito et al, 2002, Chareerat et al, 2006). Ongoing study in the composition and microstructure after the chemical reaction of polymerization has also been proposed and investigated in this paper. The knowledge of the use of high calcium lignite fly ash together with MK to produce geopolymer, therefore, would be beneficial to the correctly understanding and to the future use of these materials in the field of construction.