The focus of the researchers has now shifted towards the geopolymer based materials as it considered as sustainable alternative to the existing cementitious materials. This paper attempts to incorporate the binary blend of pozzolanic material to develop geopolymer composite and understand it’s mechanical and water transport performance as a building material. The combination of bottom ash and rice husk ash with fly ash as a common binder was used for development of geopolymer composite. Replacement levels of both bottom ash and rice husk ash was kept at 40%, 30% and 20% of total solid proportions. Also, the molarity of NaOH was provided at 12 M and 14 M levels respectively. The results showed that the blend of FA-BA blend to be better performed against the blend of FA-RHA blend for their mechanical and water transport properties. The compressive strength of the geopolymer composite having blend of fly ash and bottom ash reached to the value of 41.49 MPa due to its suitable Si/Al ratio for geopolymerization reaction, which is quite remarkable. Also, the results of water transport performance shows the blend of FA-BA to be 15-20% more resistant to percolation of water as compared to FA-RHA blended geopolymer composite, thus lowering the risk of damages to the structures.