Temperature susceptibility of asphalt binder modified with palm oil mill sludge

Modification of asphalt binder is continuously gaining interest as a result of the depletion of this non-renewable materials and their expensive price. There is a drive to use modifiers in asphalt including agricultural waste. In this study, palm oil mill sludge (POMS) was employed. The penetration grade of 60/70 as base binder incorporating with 1%,2%,3%,4% and 5% POMS were investigated for temperature susceptibility. These modified binders were tested for penetration, softening point, and viscosity. Subsequently, the penetration index (PI), penetration-viscosity number (PVN), activation energy (Ea) and viscosity-temperature susceptibility (VTS) were used to analyze the effect of POMS on the temperature susceptibility of asphalt binder. The results showed that the addition of POMS to the asphalt binder under unaged circumstances increased the penetration value from 66.56 dmm to 80.08 dmm and decreased the softening point from 49.25°C to 45.6°C for 4% POMS which indicates the softening effect of the asphalt binder. In contrast, following short-term ageing, the penetration value decreased as the softening point increased, showing that the modified asphalt binder stiffened after aging. According to the PI, PVN, Ea and VTS values of the modified POMS asphalt binder, the addition of POMS decreased its temperature susceptibility. Based on the ranking, 4% POMS was found as the best concentration of asphalt binder modifier. In conclusion, the use of appropriate amounts of POMS as an asphalt modifier is possible and provides a possible way to reuse POMS.