Durability performance of Palm Oil Fuel Ash-based Engineered Alkaline-activated Cementitious Composite (POFA-EACC) mortar in sulfate environment

This paper presents an investigation into the durability performance of Palm Oil Fuel Ash-based Engineered Alkaline-activated Cementitious Composite (POFA-EACC) mortar exposed to sulfate environment. Cube specimens measuring 50 mm × 50 mm × 50 mm were prepared from POFA-EACC and exposed to the sulfate solutions after one day of heat curing. The POFA-EACC mixtures were prepared with 100% POFA, 2% volume fraction of polyvinyl alcohol (PVA) fibres, alkali-activator (Na₂SiO_3(aq)/NaOH_(aq)) ratios of 2.5 and different molarities (10, 12 and 14 M) of NaOH_(aq). Three salt solutions (5% Na₂SO_4(aq), 5% MgSO_4(aq) and 2.5% Na₂SO_4(aq) + 2.5% MgSO_4(aq)) were used to study the resistance of the POFA-EACC mortar specimens to sulfate for 9 months. Parameter used for the study are changes in weight, compressive strength and visual changes. SEM and XRD were employed to characterize and study changes in the microstructure of the exposed specimens. The results obtained from this study revealed that the specimens exposed to 5% MgSO_4(aq) solution have better durability performance than the specimens exposed to 5% Na₂SO_4(aq).