Effect of palm oil fuel ash (POFA) fineness on the properties of asphaltic concrete AC 14

Abstract

The nature and amount of the fines or filler (particles smaller than 75 μm) in an asphaltic concrete mixes significantly affect its design and performance. Palm oil fuel ash (POFA) is an ash obtained from the burning of waste material generated from the production of crude palm oil which is of high quantity in Malaysia. This study therefore, evaluates the effect of the fineness of POFA on the mechanical properties of asphaltic concrete AC 14. Using 4 different categories of POFA fineness (based on 30min of grinding, 60min, 90min and 120min), a number of trial mixes were prepared using the Marshall Mix design procedure with 5% POFA to arrive at asphalt concrete mixtures that fulfil the Marshall criteria. The effects of each POFA fineness category on the stability, flow, stiffness, indirect tensile strength and cantabro loss of asphaltic concrete (AC 14) mixtures at their respective optimum binder content were evaluated. The results show that Marshall stability, flow, stiffness indirect tensile strength and cantabro loss values were generally higher when POFA is grinded than that of controlled specimens, but after some period of grinding (peak of the curve), the values diminished. Hence, grinding POFA to some extent improves the properties of asphaltic concrete. Grinding POFA for up to 60 minutes gives the optimum improvement of the properties of asphaltic concrete mixes considered in this study.