Feasibility Evaluation of Waste Palm Oil Clinker Powder as a Fillers Substitute for Eco-Friendly Hot Mix Asphalt Pavement

Agro industries have produced huge amounts of waste, influencing the environment. Palm oil clinker (POC), routinely dumped from Malaysian palm oil mills, is one of these waste products. This research investigates the feasibility of using it as a filler substitute in hot mix asphalt (HMA) as an alternative avenue to utilize this waste. The waste POC powder (POCP) is comparable to the properties of the traditional fillers used-granite stone dust (GSD), according to physiochemical analysis. The POCP passes through 75 µm sieve, and 6% (w/w) of the filler was substituted by 0%, 20%, 40%, 60%, 80%, and 100% (w/w) of the GSD. HMA mixes were prepared for various percentages using the Marshall mix design to evaluate their respective optimum bitumen contents (OBC). Subsequently, at OBC, the influence of POCP on the HMA volumetric, Marshall properties, Cantabro test resilient modulus, and moisture damage tests was investigated. The study revealed that all POCP mixtures improve performance in terms of stability, stiffness, and higher resistances against moisture damage than the control mixture. The improvement could be attributed to the synergistic influence of POCP pozzolanic reaction and fineness, resulting in a thicker refined mastic between POCP and bitumen, producing more durable HMA. However, based on the study findings, 80% of POCP filler for HMA mixes can be considered the optimal content to improve its properties. In conclusion, the study depicts the viability of utilizing POCP as a replacement for conventional filler to promote sustainability and provides a proper channel for its disposal.