Compression properties of fly ash/rice husk geopolymer hybrid brick

Geopolymer, an inorganic compound exhibit a wide variety of desirable properties especially in the field of construction. The use of new geopolymer sources materials such as fly ash and rice hush ash have potential as geopolymer bricks to reduce the emission of carbon dioxide caused by ordinary Portland bricks that also indirectly contributes to global environmental impact. The parameter for fly ash and rice hush ash geopolymer brick is by fixing the solid/liquid ratio at 2.0 while the ratio of Na₂SiO₃/NaOH is 2:5 and NaOH molarity of 12 During mixing process, sample is allowed to pre-cure at room temperature to allow completion of gelling phase and then at 70°C for 24 hours to get the reliable early strength. Samples are then subjected to mechanical testing, which is compressive strength to support findings of the best formulation. The best mix design for fly ash geopolymer brick was at 2.5 with highest compressive strength at 44.2 MPa. The best mix design also correlates with highest result obtained in water absorption study.