Study on fabrication of porous geopolymer by adding sago as pore former
Loading...
Date
2016-06
Authors
Mohamad Faizal Mohd Razali
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Geopolymer is an alternative cementitious material produced by rich aluminosilicate mineral materials (Si-Al) combine with alkaline activator. Objective in this study is to introduce pores by using sago as pore former and to determine the effect of curing time and sintering process to geopolymer mortar properties. There are three composition of mortar used in this study with different sago content (10%, 20%, 30%) and each composition of mortar have different curing time (1, 3, 7 days). Fly ash, silica powder, alkaline activator (sodium silicate solution (Na2SiO3) and sodium hydroxide (NaOH) and sago were mixed together based on their composition and the mixture were put into steel cubic mold (50mmx50mmx50mm) and left at room temperature for curing process. After the mortar reach their curing time, it will be sintered at 1000°C. The physical changes of the mortar were analysed before and after sintering process. The microstructure of mortar was observed using Scanning electron microscope (SEM). Compression test were done to geopolymer mortars by using ADR-Auto 3000 from ELE instrument (ASTM C109 standard) to determine the mechanical properties. Fourier transfer infrared (FTIR) analysis used to determine the functional group exist in geopolymer mortar and X-ray Diffraction (XRD) were used to determine the phase. Besides that, Energy dispersive X-ray spectroscopy (EDX) use to measure percentage element exist in mortar. Geopolymer mortar with 10% sago content, 7 days of curing and undergo sintering process have the highest compressive strength (13.46N) compare to the other geopolymer mortar composition. The 30% sago mortar contain many pores after sintering contribute its brittleness and cannot be test for compressive strength. Longer curing days give enough time for geopolymerisation process to create strong Si-O-Al bond or Jadeite (N-A-S-H gels) while sintering process helps to speed up geopolymerisation process take place in mortar. Formation of jadeite (N-A-S-H gels) influenced the strength of the mortar. The increasing phase of jadeite increase the strength of the mortar. As sago content increase, the pores in geopolymer also increase but the ratio Al2O3:SiO2 decrease resulting low formation of jadeite. Hence the compressive strength of geopolymer mortar decrease.