Investigation of the Properties of Sugarcane Bagasse Ash as an Agricultural Waste-Based Filler in Bituminous Concrete

This study investigates the engineering properties of sugarcane bagasse ash (SCBA) as a partial replacement for mineral filler in bituminous concrete, using bagasse sourced from sugar processing operations in Jigawa State, North West Nigeria. Nigeria's sugar industry generates large quantities of bagasse residue, which is largely incinerated without value recovery, while mineral filler for bituminous concrete production relies on quarried limestone. Sugarcane bagasse is incinerated at 700 degrees Celsius and the ash is characterised for fineness, specific gravity, chemical composition, and Plasticity Index following relevant ASTM standards. Bituminous concrete mixes are prepared using 60/70 penetration grade bitumen with SCBA as a filler replacement at 0, 25, 50, 75, and 100 percent. Marshall mix design procedures are applied to determine the optimum bitumen content and evaluate stability, flow, and air void content. Rutting resistance is assessed using the wheel tracking test. Results indicate that 25 percent SCBA replacement yields Marshall stability values comparable to the control mix, while higher replacement levels progressively reduce stability due to increased filler porosity and altered bitumen-aggregate interaction. Air void content increases marginally with SCBA addition. The study recommends 25 percent SCBA as the practical upper limit for filler replacement in bituminous concrete for low-volume road applications in northern Nigeria. Keywords: sugarcane bagasse ash, bituminous concrete, Marshall mix design, filler, Jigawa State.