Development of Porous Geopolymer Materials from Meta-kaolin and Fly Ash

The present work reports on the development of cost effective porous
geopolymer materials from meta-kaolin and fly ash via an addition of three different
mechanisms to produce pores. This research focused on synthesizing the
geopolymer composites followed by characterization to analyze its physical
properties in terms of crystallinity, physical, thermal and mechanical strength.
Polymerization process of fly ash and meta-kaolin based geopolymer involved a
chemical reaction of alumino-silicate oxides (Si2O3, Al2O2) with alkaline activators
consist of the combination of sodium hydroxide (NaOH) solution and sodium
silicate (Na2O3Si) solution under high curing temperature conditions. Pore forming
agent such as baking soda, calcium metal and corn oil are added to increase the
porosity of the geopolymer sample. The geopolymer composites were characterized
using Gas Pycnometer test, Scanning Electron Microscopy (SEM),
Thermogravimetric Analysis (TGA) and Compression Test. According to SEM test,
meta-kaolin based geopolymer containing corn oil exhibit more pores compared to
other samples. This sample exhibits higher porosity at 48% porosity, however has
the lowest compression strength at 0.44 MPa. While at 16% porosity, sample with
baking soda has the highest strength at 1.08 MPa.