The aim of this study was to replace Portland cement with fly ash-based geopolymer as precursors, to serve as a binder after reacting with NaOH and Na2SiO3 activators. The test object existed in the form of a cube of size 50 x 50 x 50 mm. The mortar was treated for 28 days and then immersed in a sulfate solution at similar interval using the wet-dry cycle and non-cycle methods. The compressive strength of the geopolymer mortar was estimated as 45.90 MPa before immersion. Therefore, 35.79 MPa, 41.09 MPa, as well as 37.85 MPa were reported after submersion in the respective solutions of 5% H2SO4, Na2SO4, and NaCl, using wet-dry cycle. Based on the non-cycle approach, the resulting strength was 37.36 MPa, 43.05 MPa and 39.52 MPa correspondingly.

Keywords : Geopolymer mortar, durability, acid solution, sulfate solution, chloride solution