Compressive Strength of Concrete with Sewage Sludge Ash (SSA)

Abstract

This study was carried out to determine the density and compressive strength of concrete using Sewage Sludge Ash (SSA) as combination of cement and fine aggregate replacement. The SSA suggested replacing the cement in the concrete because it has similar Pozzolanic properties of Ordinary Portland cement (OPC). Besides that, the particle size of the SSA after incineration process is similar to the fine aggregate that used in the concrete. The incineration process of the SSA takes 2 hours at the temperature of 1000°C. The sieving process will take place after incineration process and the SSA will be used as fine aggregate replacement. The remaining SSA will be grounded with ball mill and used as cement replacement. In this study, the compressive strength design by using DOE method to achieved 30 MPa (target mean strength of 46 MPa) at 28 days. The density of the SSA concrete has higher value compare to control sample because the incineration at 1000°C will increase the density of SSA. Previous study shows that 10% of SSA replaces cement in a concrete give same compressive strength value as control sample and the acceptable percentage of fine aggregate is between 10 to 25 percentages. Comparatively, the compressive strength of concrete when SSA used as combination of cement and fine aggregate replacement also give higher value compare to control sample.