A Comparative Study on Properties of Geopolymeric Material from Coal Ash

Abstract

This project was studied on the properties of geopolymeric material from fly ash and bottom ashobtained from Mae Moh power plant in Lumpang. Bottom ash was ground to have as small as fly ashparticle. Geopolymer paste was made by mixing the ash with NaOH solution and Na₂SiO₃ solution. Themass ratio of Na₂SiO₃/NaOH was varied at 0.5, 1.0, 1.5 and 2.0 by weight using 10 M NaOH. Twomixing methods were investigated; separated mixing (S) and normal mixing (N). Pastes were then curedat 65 ^oC for 48 hours in order to study the quantities of silica compound, Si-O-Si (stretching), by FourierTransform Infrared Spectrometer (FT-IR) at frequency of 1200-950 cm-1. Microstructure and thermalproperties of paste by Differential Scanning Calorimeter (DSC) were additionally carried out. Geopolymermortar was performed for the compressive strength. The results showed that quantities of reacted siliconcompound (Si-O-Si) depended on the Na₂SiO₃/NaOH ratio and mixing method. Na₂SiO₃/NaOH of 1.0 and1.5 gave a good performance and the highest compressive strength obtaining from fly ash-based geopolymerwas up to 350 ksc.

Keywords : Geopolymer / Fly Ash / Bottom Ash