Optimum Portland Cement-Guinea Corn Husk Ash Blend as Filler in Hot Mix Asphalt

Abstract- Dwindling natural resources and the negative environmental impact that comes with the industrial processing of construction materials are the driving forces to man’s quest for cleaner (green) and cheaper alternative construction materials. Among such alternatives include agricultural wastes. Guinea corn husk ash (GCHA), an agricultural waste obtained from the incineration of Guinea corn husk, has shown potentials of been used as filler material in hot mix asphalt due to its pozzolanic properties. Thus, this research aims to assess the strength and durability properties of hot mix asphalt with the incorporation of GCHA as a partial replacement for filler (cement). Marshal mix design method was used to determine the optimum bitumen content (OBC) at no GCHA content (control mix) within the bitumen content range prescribed by Nigerian general specifications for roads and bridges (NGSRB) for bituminous courses in flexible pavements. This OBC was used to determine the optimum GCHA by replacing the primary filler with GCHA up to 45% in increments of 5%. Marshal indices and volumetric properties of samples prepared at each replacement level were determined according to relevant standards. Mixtures containing up to 20% Portland cement replacement with GCHA were found to produce competitive results against the control mix (only cement as filler). Thus, Marshall indices and volumetric properties of mixtures containing up to 20% cement replacement GCHA satisfy the minimum