Chiang Mai Journal of Science

     This study explored the utilization of waste palm oil fuel ash (PA) as a supplementary cementitious material to enhance the properties of blended Portland cement mortar. By examining the impact of PA with varying degrees of fineness, the research demonstrated how different levels of PA fineness influenced the physical and durability properties of mortar. Specifically, Portland cement type I (OPC) was substituted with PA at three distinct fineness levels, each constituting 20% of the binder’s weight. The experiments maintained a consistent water-to-binder (W/B) ratio of 0.55 and utilized a superplasticizer to preserve the standard mortar flow of 110 ± 5 %. Findings indicated that finely ground PA significantly decreased mortar porosity while enhancing compressive strength, water absorption, and chloride penetration resistance. SEM-XRD pattern analysis further revealed a more homogeneous microstructure in mortars containing finely ground PA, characterized by an increased presence of calcium silicate hydrate (C-S-H). The results suggest that ground PA not only mitigated environmental issues related to the disposal of palm oil fuel ash but also promoted its sustainable use in construction materials, thereby offering dual benefits of enhancing material properties and reducing environmental impact.