Bonding and Phases Analysis of Geopolymer Materials

Abstract

This paper presents the bondings and mineral phases exist in geopolymer material consist of raw fly ash, raw metakaolin and also fly ash and metakaolin blend geopolymer. Fly ash used is a waste materials from Lumut power plant by combusting coal while metakaolin was obtained by calcining the kaolin at 750 C for 4 hours. Alkaline activators that act as binder were sodium silicate (Na2SiO3) solution and sodium hydroxide (NaOH) solution with the ratio of Na2SiO3/NaOH is 2.5 to 1. The samples undergo Functional Group Identification (FTIR) and Phase Analysis (XRD). FTIR results show that after geopolymerization process, the band shifted to lower wavenumber (776 cm-1 ) due to interaction of Al atoms in the silicate geopolymer network because of higher cross-linking. XRD results show mineral phases of quartz and mullite in geopolymer after geopolymerization process and it can be said that not all mineral phases from raw material participating in formation of geopolymer matrix.