Performance evaluation of asphalt binder modified with olive mill wastewater ash (OMWA)

Abstract. Olive mill wastewater (OMW) is a liquid by-product generated from olive oil processing and represents a significant environmental concern regarding their disposal and management. This paper was carried out to examine the potential use of the Olive Mill Wastewater Ash (OMWA) as a modifier for asphalt binder. An asphalt binder with a penetration grade of 60/70 was used as the control binder in this study. OMWA was added to the base asphalt binder at various amounts (1%, 2%, 3%, 4%, and 5% by weight of asphalt binder). Asphalt binder's physical and rheological properties, such as penetration, ductility, softening point, flash/fire points, and rotational viscosity, were investigated. The laboratory test results revealed that increasing the amount of OMWA in the asphalt binder blend decreased penetration and ductility while increasing the softening point, rotational viscosity, and fire and flash of OMWA-modified asphalt binder. Hence, it is recommended that the OMWA modifier be used in warm regions to resist the plastic deformation of asphalt mixtures. This approach demonstrates the potential for converting waste into a valuable resource in infrastructure development, thereby improving both sustainability and road construction performance.