Microstructure of Self-Consolidating High Strength Concrete Incorporating Palm Oil Fuel Ash

This paper mainly focuses the effect of palm oil fuel ash (POFA) on the microstructure of self-consolidating high-strength concrete (SCHSC). POFA has been used as a supplementary cementing material replacing ordinary portland cement (OPC) in the range of 0-30%. SCHSC mixes were produced with the water-to-binder (W/B) ratios of 0.25-0.40 to obtain high strength. The microstructure of 28 and 56 days old concretes was analyzed based on their scanning electron micrographs (SEMs) in the cases of 0 and 20% POFA contents. The influence of POFA on the 28 and 56 days compressive strength and permeable porosity was also investigated. The experimental results showed that a POFA content up to 20% increases the compressive strength of SCHSC compared with that of the control concrete due to the reduced permeable porosity. The SEMs of the concretes revealed that POFA contributes to producing a denser microstructure, which increases the compressive strength and reduces the permeable porosity of SCHSC.