Efficiency Factor of Palm Oil Fuel Ash in Concrete

This article reports the results on the determination of the efficiency factor (k) of palm fuel oil ash (POFA), which can be used for the design of concrete mixture. The method was applied from the British Standard that recommends the calculation of the k-value, so as to be able to determine the content of POFA as an ingredient in Portland cement that exhibits equivalent efficiency as sole Portland cement. Such use would clearly lead to the promoted use of POFA in concrete mixture. The research aimed to determine the efficiency factor of POFA by collecting data from other research studies, taking into account the fineness, percent replacement of POFA and curing age of concretes containing POFA as adapted from the Abrams’ law and Bolomey’s law equations. Multi-linear regression analysis was then performed to determine the k-value of POFA when the concretes were aged at 7, 28 and 90 days. The results indicated the k-value (Kd) of POFA at 7 days (k7) was 0.75, R2 =0.99. When the age increased to 28 days, k28 was 0.73, R2 =0.96, while k90 was 0.81 with R2 =0.95. In addition, use of the equations in the design of concrete mixes was introduced. The results of the compressive strength as calculated by the equation were compared with those from the research. The results on k28 at 28 days exhibited percent error of 7.5%.