Influence of palm oil fuel ash as a modifier on bitumen to improve aging resistance

The abundance and increase of waste from palm oil mills in recent years has led to environmental pollution. This problem can be addressed by recycling and reusing such waste materials. In this study, palm oil fuel ash (POFA), a by-product of palm oil mills, was used as a bitumen modifier under normal conditions and subjected to aging. The properties of the modified bitumen were investigated in terms of penetration, softening point, penetration index, penetration-viscosity number, and viscosity tests. Two laboratory simulation aging methods were conducted in this study: the standard rolling thin film oven test and the pressure aging vessel test. Experimental results show an increase in the softening point and a decrease in the penetration of the bitumen mixed with POFA. The addition of POFA, especially in large amounts, increased the temperature susceptibility of the bitumen. The use of POFA as a bitumen modifier generally reduces the aging effect on the physical and rheological properties of bitumen, as indicated by the reduced aging index of viscosity.