Reuse of Industrial Sludge as Pelletized Aggregate for Concrete

Abstract

Industrial sludge is generated at a rate of 100 metric tons/day, from a copper slag recycling plant. The industrial sludge is currently being landfilled. However, limited availbility of landfill sites has raised the need of an alternative disposal. A renewed interest in converting the industrial sludge into construction materials has been prompted to achieve a viable disposal option in saving the depleting natural resources of raw materials as well as the environment. This study describes the use of sintered sludge pellets as a complete replacement for regular granite aggregates in concrete. The pelletized sludge was fired to a temperature of 1,135°C at which the sintering process occurs, producing a hard fused basalt-like mass. In comparison with normal granite aggregates, the sintered sludge pellets display a higher aggregate strength, a higher porosity, and a lower aggregate density that manifests attributes better than that required of construction aggregates. The concrete cast with the pelletized aggregtes achieved a compressive strength of 38.5 N/mm