Evaluation of sawdust ash as a partial replacement for mineral filler in asphaltic concrete

Abstract

This paper evaluated the effects of sawdust ash on the characteristics of asphaltic concrete with a view to investigating its suitability as an additive in asphaltic concrete. The sawdust was obtained from Alekuwodo in Osogbo, Osun state, Nigeria. The bitumen, coarse aggregates, fine aggregates, and mineral filler were obtained from Espro Asphalt Plant, Ife- Ibadan Road, Osun state, Nigeria. The sawdust was burnt into ash using a furnace at a temperature of 800°C, allowed to cool and sieved through 75 μm BS sieve (No.200). The properties of the materials were determined using standard procedures. Asphaltic concrete samples were prepared with sawdust ash at 0, 5, 10, 15, 20, and 25 % by weight of the granite filler. The samples were subjected to Marshall Stability test. The stability, flow, density, voids filled with bitumen (VFB), air voids (AV) and voids in mineral aggregate (VMA) were determined. The values of stability, flow, bulk density, voids filled with bitumen, air voids and voids  filled in mineral aggregates at 15 % optimum sawdust content were, 18.2 kN,3.40 mm, 2.36 g/cm³ , 77.13 %, 4.05 % and 17.71 %, respectively. The result showed that, the inclusion of sawdust ash in asphaltic concrete improved its properties.

Keywords: Sawdust Ash, Asphaltic Concrete, Asphaltic Concrete Properties