Pozzolanic reactivity of ultrafine palm oil fuel ash waste on strength and durability performances of high strength concrete

Palm oil fuel ash (POFA) was utilized as a pozzolanic material in varied quantities to produce high-strength concretes (HSCx) of above 90 MPa, with significant improvement in its engineering and fluid transport properties. The chemical and physical characteristics of ultrafine POFA (U-POFA) utilized in HSCx were investigated along with its concomitant fresh, strength and durability characteristics compared to ordinary Portland cement based type (OPC-HSC). The U-POFA had high surface area of (1.136 m2/g-Blaine), mean particle size (2.06 μm), and glassy phase (70.59%). The HSCx that had replacement level of 0, 20, 40 and 60% of U-POFA recorded the 90-day strength of 100.5, 105.2, 109.0 and 108.5 MPa. Utilizing high volume of POFA in HSCx is possible with improved fineness and heat-treatment at 500 ± 50 °C, and could retard water absorption/permeability, setting and chloride penetration/migration rates and achieve better strength. This makes HSCx a better choice in terms of strength and durability for hot weather and underwater concreting, and in corrosive or aggressive environment.