Study on Geopolymer-type Coating Using Blended Fly Ash and Palm Oil Fuel Ash (POFA)

Inorganic polymer, most commonly known as 'geopolymer', is generically used as a
term to describe the amorphous to crystalline reaction products from the reaction of
alkali alumina-silicates with alkali hydroxide or alkali silicate solution. Biomass
wastes have been lately research as raw materials for geopolymer process in the
application of coating. The study was focused on the use of palm oil fuel ash (POFA)
as a novel green material with high adhesive strength and slow setting time for
application in steel coating. The main variables for the geopolymer produced were
solid/liquid ratio and addition of POFA. It has been observed that the setting time
and adhesive strength influenced by the water content in the initial mixture and
strongly depended on geopolymer composition. Higher solid/liquid ratio will result
in shorter setting time. Highest adhesive strength of 12.5MPa is achieved on steel
substrates at higher water content mixture with the addition of 25% of POFA. It is
believed that the utilization of POFA could be optimized and has a great potential to
be developed as geopolymer-based coating materials.