Performance of Palm Oil Fuel Ash and Rice Husk Ash Based Geopolymer Mortar

Geopolymer is a cement free material which uses binder produced by the reaction of the alkaline liquid solution with binding agents. In this study, the performance of geopolymer mortar using Palm Oil Fuel Ash (POFA) and Rice Husk Ash (RHA) as binding agents was carried out. The tests conducted in this research were Specific Gravity, X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), bulk density and compressive strength at 7th, 14th and 28th days. The results show both POFA and RHA materials fulfilled the criteria as a pozzolanic material. Meanwhile, the cement based mortar has the highest bulk density, followed by POFA based and RHA based geopolymer mortar. The cement based mortar was also identified to have the highest compressive strength due to its densest structure. However, it was found that the RHA based geopolymer mortar has higher compressive strength than the POFA based geopolymer despite its lower density. This is due to the high silica content in RHA which promote more silica-oxygen-silica bonds than POFA.