A New Pozzolanic Material from Palm Oil Fuel Ash

Abstract

Palm oil fuel ash (POFA) is a by-product from burning process in thermal power plant, which palmnutand fiber of palm are burnt at temperature about 300-400 ÌC. Each year, more than 100,000 tons of POFA hasbeen disposed and tended to increase annually. From the study of the chemical composition, it was found thatthe POFA could be used as a pozzolana. In this study, the quality of POFA was improved by grinding until themedian particle sizes were 19.9 and 10.1 microns. The unground and ground POFA were used to replacePortland cement type I at 0 to 40% by weight of binder. Setting time, water requirement and compressivestrength of mortars at the age of 7, 28, 60 and 90 days were investigated.

The results revealed that the replacement of POFA in Portland cement increased setting time of paste.For constant flow of 105-115, the mortar mixed with POFA required higher water than that of standard mortar.After grinding, the use of ground POFA reduced setting time as compared to that of unground POFA paste anddecreased water requirement. Compressive strength of unground POFA mortars were less than those of standardmortar. The unground POFA is not suitable to use as a pozzolanic material due to large particle size and highporosity. However, mortars with ground POFA (d50 = 19.9 and 10.1 microns) at 20% of cement replacement givesthe compressive strength higher than 75% of standard mortar at the age of 7 and 28 days. In addition, the useof 10 and 20% of high fineness POFA (d50 = 10.1 microns) gives higher compressive strength of mortar than thatof standard mortar and it is 104 and 101%, respectively at the age of 90 days. The results suggest that the groundPOFA can be used as a good pozzolanic material.